University of Kansas Publications

Museum of Natural History

Volume 7, No. 9, pp. 513-582, 4 pls., 1 fig. in text, 12 tables

November 15, 1954

Mammals of the San Gabriel Mountains

of California

BY

TERRY A. VAUGHAN

University of Kansas

Lawrence

1954

University of Kansas Publications,
Museum of Natural History

Editors: E. Raymond Hall, Chairman, A. Byron Leonard,

Robert W. Wilson

Volume 7, No. 9, pp. 513-582, 4 pls., 1 fig. in text, 12 tables

Published November 15, 1954

University of Kansas

Lawrence, Kansas

PRINTED BY

FERD VOILAND, JR., STATE PRINTER

TOPEKA, KANSAS

1954

25-5184

MAMMALS OF THE SAN GABRIEL MOUNTAINS

OF CALIFORNIA

by

Terry A. Vaughan

CONTENTS

•  PAGE


• Introduction
  515


• Description of the Area
  516


• Biotic Provinces and Ecologic Associations
  518


• 
  
  • Coastal Sage Scrub Association
    521
  
  
  • Southern Oak Woodland Association
    523
  
  
  • Chaparral Association
    524
  
  
  • Yellow Pine Forest Association
    526
  
  
  • Pinyon-juniper Woodland Association
    527
  
  
  • Sagebrush Scrub Association
    530
  
  
  • Joshua Tree Woodland Association
    530
  
  


• Accounts of Species
  531


• Literature Cited
  581

Introduction

This paper presents the results of a study of the mammals of
the San Gabriel Mountains of southern California, and supplements
the more extensive reports on the biota of the San Bernardino Mountains
by Grinnell (1908), on the fauna of the San Jacinto Range by
Grinnell and Swarth (1913), and on the biota of the Santa Ana
Mountains by Pequegnat (1951).

The primary objectives of my study were to determine the present
mammalian fauna of the San Gabriel Mountains, to ascertain the
geographic and ecologic range of each species, and to determine
the systematic status of the mammals. In addition, certain life
history observations have been recorded.

Field work was done in the north-south cross section of the
mountains from San Gabriel Canyon on the west, to Cajon Wash
on the east; and from the gently sloping alluvium at the Pacific base
of the mountains at roughly 1000 feet elevation on the south, over
the crest of the range to the border of the Mojave Desert at an elevation
of 3500 feet on the north. Camps were established at many
points in the area with the object of collecting the mammals of each
association and each habitat. Field work was begun in the San[Pg 516]
Gabriels in November 1948, and was carried on intermittently
until March 1952. I was unable to carry on field work in any
summer.

Fig. 1.
Map of the San Gabriel Mountain area showing the positions of places
mentioned in the text.

Description of the Area

The San Gabriel Mountains are approximately sixty-six miles
long, and average twenty miles wide. The main axis of the range
trends nearly east and west, and extends from longitude 117°25'[Pg 517]
to longitude 118°30'. The widest part of the range is bounded by
latitude 34°7' and latitude 34°30'.

The San Gabriel Mountains connect the Sierra Nevada with the
Peninsular Ranges of southern California and Baja California. On
the west the San Gabriels are bordered by the Tehachapi Mountains,
which stretch northeastward to meet the southern Sierra
Nevada; to the east, beyond Cajon Pass, the San Bernardino Mountains
extend eastward and then curve southward to the broad
San Gorgonio Pass, from which the San Jacinto Range stretches
southeastward to merge with the Peninsular Ranges.

The rocks comprising the major part of the San Gabriel Mountains
probably were intruded in Late Jurassic times, with severe metamorphic
activity taking place concurrently. A long period of erosion
followed after which deposition took place during much of the
Tertiary. Deformation and uplift beginning in Middle Miocene
times resulted in the formation of east-west-trending faults along
both sides of the range. By repeated movements along these faults
the Late Jurassic crystalline rocks were lifted above late Tertiary
and Quaternary sediments and elevated above the surrounding
terrain. Continued uplifts in post-Pleistocene time together with
erosion in Recent times have shaped the San Gabriel Mountains
(Oakeshott, 1937).

The alluvial slopes at the coastal base of the range give way to
the foothills at roughly 1800 feet elevation; whereas the Mojave
Desert merges with the interior foothills at elevations near 4000
feet. The crest or drainage-divide of the range varies from 6000
to 8000 feet in elevation, and many peaks are more than 8000 feet
high. San Antonio Peak, the highest peak of the range, rises to an
altitude of 10,080 feet. The mountains are characteristically steep
and the slopes are deeply carved by canyons, the larger of which
have permanent streams. The abruptness of the Pacific slope is
in many places impressive. The horizontal distance from the top
of Cucamonga Peak, at an elevation of 8911 feet, to the base of the
coastal foothills directly to the south, at 2250 feet, an elevational
difference of 6661 feet, is only 3.8 miles. From the base of Evey
Canyon, at 2250 feet, to an unnamed peak to the northwest with
an elevation of 5420 feet, the horizontal distance is 2.1 miles. Because
of the steep, rocky nature of many of the slopes and the
lack of soil on them, vegetation may be sparse even at high elevations.
There are few meadows in the mountains.

Because the San Gabriels stand approximately thirty miles from
the Pacific Ocean and are a partial barrier to Pacific air masses[Pg 518]
sweeping inland, the desert side and the coastal side of the range
differ climatically. The coastal slope receives much heavier precipitation
than the desert slope. The precipitation, for 1951, of 25.36
inches recorded at the mouth of San Antonio Canyon on the Pacific
slope contrasts with 7.17 inches recorded at Valyermo at the desert
base. Nearly all of the precipitation comes in winter. The higher
parts of the range, above approximately 5000 feet, receive much of
their mid-winter precipitation in the form of snow. Snow often
extends down the desert slope well into the Joshua Tree belt. When
there are heavy winter rains the channels of the usually dry washes
are filled with rushing, turbid water. There are striking differences
in temperature between the two sides of the range and between the
lower elevations of the mountains and the higher parts. For
example, in December 1951, the mean temperature at the base of
San Antonio Canyon (2225 feet) at the coastal foot of the range
was 55.4°F, while at Llano (3764 feet) at the desert base it was
43.7°F. In this same year the December mean for Table Mountain
(7500 feet), on the desert slope, was 33.4°F. The temperature
means for July, 1951, at San Antonio Canyon, Llano, and Table
Mountain, were 77.3°F, 82.1°F, and 69.2°F respectively. The
weather records for 1951 were used for illustration because average
temperature and average precipitation for many other years are
lacking for most of the weather stations in the area. There is an
important difference in the humidity on the two sides of the range,
but actual data are not available. At certain times, especially in
spring, fog banks moving in from the Pacific Ocean frequently
blanket the coastal base of the mountains and the foothills. On
such days the fog generally "burns off" in the morning, but may
persist into the afternoon or throughout the day. Never in my
experience has fog spilled over the main part of the range far onto
the desert slope, although the fog may push through the lower
passes to be dissipated quickly in the dry desert atmosphere. The
obvious differences in the biota on the two sides of the range are
probably due to the contrasting climates.

Biotic Provinces and Ecologic Associations

Because of the elevational extremes and attendant climatic contrasts
in the San Gabriel Mountains, there is a rather wide range of
environmental conditions. Four life-zones are represented: Lower
Sonoran, Upper Sonoran, Transition, and Canadian. Within these
zones certain ecologic communities can be recognized; these rep[Pg 519]resent
several biotic provinces. Table 1 shows the relationships
between the environmental categories recognized by the writer in
the San Gabriel Mountains. The biotic province and ecologic
community system is that developed by Munz and Keck (1949),
and the life-zone system is that of Merriam (1898).

Table 1.—Relations of the Major Environmental Categories of the
San Gabriel Mountains.

The Californian Biotic Province dominates the biotic aspect of
the coastal slope of the range. Thirty-nine out of the seventy-two
mammals recorded from the San Gabriels are typical of this Province.
The coastal sage-flats at the Pacific base of the mountains and
the vast tracts of chaparral of the coastal slope are included in this
Province.

Forming a hiatus between the Pacific and the desert slope is the
Sierran Biotic Province consisting of coniferous forests on the crest
of the range. The chipmunk (Eutamias speciosus speciosus) and
the introduced black bear (Ursus americanus californiensis) are
the only two mammals which can be considered typical of this
area. On the higher peaks of the range, such as Mount San Antonio
and Mount Baden Powell, the Canadian Life-zone is represented
by certain boreal plants.

At scattered points along the crest of the range and on the desert
slope, the Nevadan Biotic Province is represented by the sagebrush
scrub association. No mammals can be considered typical of this
region.

The Southern Desert Biotic Province occurs below 6000 feet elevation
on the interior slope of the range, and markedly influences[Pg 520]
the mammal fauna of this slope. Twenty-one species of mammals are
typical of this Province.

Coastal Sage Scrub Association

This association is restricted to the Pacific base of the range, is
typical on the alluvium at the bases of the coastal foothills, and
usually grades into the chaparral at about 1800 feet elevation.
When seen from above, the rather level terrain of the association
is broken sharply at the mouths of canyons by dry washes, and is
limited below, to the south, by cultivated land. The coastal sagebrush
is the most characteristic plant of this association, occurring
in all undisturbed parts of the area.

There are several habitats within the coastal sage scrub association.
These differ from one another chiefly on the basis of soil
type. The soil of the rather level sageland in most places is rocky
or gravelly, or, as adjacent to washes, it is finely sandy in texture, and
supports the major plants of the association. Most of the eroded
adobe banks at the bases of the foothills support these same plants,
with white sage being the dominant species. Locally, as in damp
hollows or cleared areas, there is grassland. Jumbles of boulders,
sand, gravel, and steep cutbanks, are characteristic of the channels
of dry washes, these areas supporting sparse vegetation. The fauna
and flora of the washes are distinct from those of surrounding sage
flats. Because they are included within the geographic limits of the
coastal sage belt, however, the washes are discussed along with
this association.

The abruptness with which one habitat gives way to another in
this association causes sharp dividing lines between the local ranges
of certain mammals. For example, in trap lines transecting dry
washes and level sageland two assemblages of rodents were found.
That part of the line amid the boulders and cutbanks of the wash[Pg 522]
took mostly Peromyscus eremicus fraterculus and Neotoma lepida
intermedia, while Perognathus fallax fallax, Dipodomys agilis agilis,
and Peromyscus maniculatus gambeli were taken in the adjacent
sage flats. The steep adobe slopes of the foothills, which constitute
the upper part of the coastal sage scrub association, are commonly
inhabited by Peromyscus californicus insignis, which rarely occurs
in the level tracts of sage a few yards away. Thus, this association
is not homogeneous with regard to its rodent population; many of
these species have local and discontinuous distributions.

The following list gives the results of about 500 trap nights (a
trap night equals one trap set out for one night) in typical coastal
sage-scrub association one-half mile southwest of the mouth of San
Antonio Canyon, at 1700 feet elevation.

Table 2.—Yield of 500 Trap-nights in the Coastal Sage Scrub
Association.

The list below indicates the catch in 200 trap nights in San Antonio
Wash, at 1700 feet elevation and within the realm of the coastal
sage; all of the traps were set in rocky and sandy main channels of
the wash.

Table 3.—Yield of 200 Trap-nights in San Antonio Wash.

[Pg 523]

The prickly-pear cactus is of obvious importance to certain mammals
of the coastal sage belt. This cactus is most common in disturbed
areas such as sandy flats bordering washes, eroded adobe
banks, and land once cleared by man. In these areas it is often the
dominant plant with respect to area covered, usually growing in
dense patches each covering approximately 150 square feet. It
provides substitute nesting sites for Neotoma lepida in areas devoid
of rock piles, and is probably the major factor governing the distribution
of this wood rat in the sageland. Cottontails and brush
rabbits use prickly-pear cactus extensively as refuge. Their forms
and short burrows can be seen beneath many of the clumps of cactus.

This cactus serves as food for many mammals at least in the fruiting
period in the fall. Usually only the fruit is eaten, but some pads are
chewed by rabbits. The fruit or seeds of this plant are eaten by
striped skunks, gray foxes, coyotes, pocket mice, kangaroo rats,
wood rats, and probably white-footed mice.

The coyote is the dominant carnivore of the coastal sage flats.
Many individuals spend the day in the adjacent chaparral-covered
foothills and travel down into the flats at night to forage.

This association is limited to the Pacific slope of the mountain
range, occurs in the mouths of canyons and on the floors of canyons,
and extends up the larger canyons to 4000 feet elevation or higher.
In a few areas on the flats at the coastal base of the range the oaks
replace the coastal sage.

The large oaks forming an overhead canopy and the lack of much
undergrowth give the oak woodland a shaded parklike appearance.
Few brushy or herbaceous plants grow in the mull-laden soil beneath
the oaks. Some grasses, however, are present locally.

Two habitats are found in the oak woodland: the pure oak
woodland and the riparian. Much of the oak woodland is in canyons
and therefore near streams or seepages. The larger streams
have bordering growths of alders, willows, and blackberries, inhabited
by meadow mice and shrews that are normally absent from
the adjacent oak woodland. Neotoma fuscipes macrotis and Peromyscus
californicus insignis are commonly found in the riparian
[Pg 524]
habitat, and Peromyscus boylii probably reaches peak abundance
in the stream-side thickets and tangles of plant debris.

The rather open floor of the oak woodland is relatively devoid
of mammal life. Peromyscus californicus and Peromyscus boylii,
the only ground-dwelling rodents commonly found here, usually
are taken near the limited areas of brushy growth, or the shelter
afforded by logs and fallen branches. The paucity of shelter for
small mammals seems to be an important factor limiting rodent
populations in the oak woodland.

In the foothills of the San Gabriels the gray squirrel is restricted
to the oak woodland, even though this association may be represented
by only a narrow strip of canyon bottom oak trees. The
presence or absence of "bridges" of oak woodland between mountains
which are centers of gray squirrel populations and nearby
ranges has probably been a major factor influencing the present
geographic distribution of this animal.

The raccoon is the most abundant carnivore of the oak woodland,
being especially common in the riparian habitat.

This association is characteristic of the Pacific slope of the San
Gabriels and extends from roughly 2000 feet elevation to 5000 or
6000 feet elevation. The ecotone between the chaparral and yellow
pine forest associations covers a broad elevational belt, with chaparral
following dry slopes up into coniferous forests, and conifers extending
down north slopes surrounded by chaparral.

The chaparral association is characterized by tracts of dense
brushy plants. These plants are from three to ten feet tall, their
interlacing branches often forming nearly impenetrable thickets.
Typically little herbaceous growth is present beneath the chaparral,
the ground being covered with varying amounts of mull.

The effects of fire, slope, exposure, and elevation, make the
chaparral association extremely varied with regard to habitats or
plant formations. There are nearly pure stands of greasewood on
the lower arid slopes; scrub oak, sumac, and lilac clothe less dry
[Pg 525]
exposures; scrub oak and bay trees occur commonly amid granite
talus; and locally groves of bigcone-spruce are found. Because
of the many habitats present, and the difficulty of collecting in the
chaparral, less was learned of the ecology of the mammals in this
association than of those occurring elsewhere. The distribution of
several chaparral-inhabiting mammals seems to be influenced by
the distribution of locally characteristic plants, for example oak and
bay woodland, or greasewood chaparral.

Several habitats within the chaparral community support few
species of mammals and few individuals. Possibly the compact,
rocky nature of the soil limits burrowing rodents, and the lack of
herbaceous growth limits the food supply. Steep rocky slopes in
San Antonio Canyon grown to mountain-mahogany and scrub oak
were sparsely populated by Peromyscus boylii rowleyi, Peromyscus
californicus insignis, and Neotoma fuscipes macrotis. Fifty traps
set on such a slope for one night caught only three Peromyscus.
Traps set in tracts of greasewood brush on dry south slopes at the
head of Cow Canyon produced only California mice, Peromyscus
californicus insignis Rhoads.

Following is a list of the mammals taken in the course of approximately
600 trap nights in the lower parts of the chaparral belt.
All of the traps were set on slopes in San Antonio Canyon below
4000 feet elevation. The list gives a general indication of the relative
numbers of rodents inhabiting one chaparral habitat: the arid
greasewood-covered south slopes of the lower chaparral belt.

Table 4.—Yield of 600 Trap-nights in Greasewood Chaparral.

Heteromyids are evidently absent from the upper parts of the
chaparral association, but cricetid rodents are common there beneath
heavy clumps of lilac and in the talus beneath oaks and bay
trees. The following list gives the mammals taken in the course
of about 200 trap nights in the granite talus one half mile northwest
of the mouth of Icehouse Canyon, at 5200 feet elevation.

[Pg 526]

Table 5.—Yield of 200 Trap-nights in the Upper Part of the Chaparral Association.

The gray fox is the dominant carnivore of the chaparral association
and forages widely in all habitats.

The crest of the range, from the upper limit of the chaparral
association at roughly 6000 feet to the limited areas of boreal flora
above 8500 feet elevation, is covered by yellow pine forests. On the
desert slope of the range the coniferous forests which extend down
to about 6000 feet represent the best development of this association,
while the coniferous forests on the coastal side of the drainage divide
are often more or less diluted by chaparral elements. For example,
yellow pines on the Pacific face of Blue Ridge at 7000 feet elevation
often grow in association with scrub oak and mountain-mahogany.

Few mammals are resident in the typical yellow pine forest as
characterized by dense coniferous timber and little herbaceous or
brushy growth. Here most of the species recorded actually find
optimal conditions in an adjacent habitat. The forest probably
harbors surplus individuals from adjacent preferred habitats, or, as in
the case of chipmunks and ground squirrels, the forest often serves
as forage ground while nearby brushy areas are utilized for breeding
and shelter. The abundance of birds in the timber contrasts strikingly
with the paucity of mammals there. The lack of a seed-producing
understory, and the open duff-covered stretches of ground on
which rodents would be extremely vulnerable to predation, probably
in part account for the scarcity of rodents.

Within the general area encompassed by the yellow pine forest
there are two major habitats, namely coniferous forest and chaparral.[Pg 527]
The species of plants comprising the chaparral of the Transition
Life-zone are different from those comprising the chaparral of the
Upper Sonoran Life-zone on the Pacific slope. In the chaparral of
the Transition Life-zone, basin sagebrush and snowbrush grow in
extensive patches in clearings in the timber. Dense thickets of choke
cherry cover many damp hollows, and these thickets harbor the
houses of Neotoma fuscipes. The food and shelter afforded by these
chaparral areas importantly influence the local distribution of
rodents: for example, Dipodomys agilis and Perognathus californicus
in the yellow pine area are found only in association with chaparral,
being completely absent from wooded areas.

The severe winter weather in this association must force many of
the mammals into periods of inactivity. Probably during the long
periods in the winter when snow covers the ground the heteromyids
and sciurids remain below ground.

In the San Gabriel Mountains this association is limited to the
desert slope and reaches its lower limit at the bases of the foothills
and extends up to the lower edge of the yellow pine forests. The
altitudinal extent of the pinyon-juniper association is from roughly
4000 to 6000 feet elevation.

Several habitats are evident within the pinyon-juniper belt. On
north slopes in the upper part of this association, scattered stands
of pinyon pines are found with dense patches of scrub oak intervening,
while on other such slopes a dense chaparral is present, consisting
primarily of scrub oak, mountain-mahogany, and California
slippery-elm. In this type of chaparral several hundred trap nights
yielded only two rodent species: Neotoma fuscipes simplex and
Peromyscus truei montipinoris. There are few pinyons on the south
slopes, especially in the lower parts of the association; many of these
slopes are clothed with an open growth of manzanita and yucca,
while northern exposures there support mostly scrub oak. Many
of the flats of the pinyon belt are grown to basin sagebrush.

Following is a list of the mammals taken in about 400 trap
nights at one locality in the pinyon-juniper association. The area
supported a mixed growth of pinyon, scrub oak, mountain-ma[Pg 528]hogany,
and antelope-brush, together with smaller brushy plants,
and was at the head of Grandview Canyon, at an altitude of roughly
5000 feet.

Table 6.—Yield of 400 Trap-nights in the Pinyon-juniper Association.

Although Munz and Keck (1949:101) considered the pinyon-juniper
belt as one association, on the desert slope of the San
Gabriels pinyons and junipers do not generally grow on common
ground; but rather the juniper belt represents a well defined habitat
occurring between the pinyon covered slopes and the flats that support
Joshua trees. Because the mammalian populations of the
pinyon belt and the juniper belt are somewhat different, the mammals
of these areas are most conveniently taken up separately.

In the juniper belt the juniper tree is of marked ecologic significance;
the distribution of Peromyscus truei and Neotoma fuscipes
is determined here by the presence of junipers. At certain
times of year the fruit of this plant is eaten by coyotes, kangaroo
rats, and wood rats.

The list below indicates the results of approximately 500 trap
nights in the juniper belt near Mescal Canyon, between 4000 and
5000 feet elevation.

Table 7.—Yield of 500 Trap-nights in the Juniper Belt.

[Pg 529]
The biota of the washes that cut through the juniper belt in and
below many of the larger canyons differs from that of the surrounding
juniper-clad benches. Because the washes are in the same
geographic area as the juniper belt they are discussed together.
These washes on desert slopes are densely populated by rodents
derived from adjacent areas, and support vegetation typical of
higher floral belts in association with xerophytic, typically desert,
species. In a sense, the washes serve to mix up the mammals of adjacent
areas. For example, Onychomys torridus pulcher and Peromyscus
eremicus eremicus, which are mammals typical of the
desert, were found in Mescal Wash above their usual desert range;
and Peromyscus californicus insignis and Peromyscus boylii rowleyi,
which are chaparral inhabiting mammals, were found in the wash
far removed from their chaparral environment. Washes are evidently
effective agents in facilitating the dispersal of certain species
of mammals. It is easy to envision a species crossing hostile
habitats via dry washes to invade suitable niches in an area which
is geographically and ecologically isolated from the original home
of the species. Approximately 500 trap nights in Mescal Wash,
at 4100 feet elevation, in the lower edge of the juniper belt, yielded
the following mammals:

Table 8.—Yield of 500 Trap-nights in Mescal Wash (Desert Slope).

Dipodomys panamintinus mohavensis, Neotoma fuscipes simplex,
and Peromyscus truei montipinoris are probably the most characteristic
mammals of the pinyon-juniper association.

This association is found on only the crest and desert slope of the
range between 5000 and 8000 feet elevation. There it characteristically
occupies flats and clearings in the yellow pine forest and
pinyon-juniper woodland. The dominant plant of the association
is basin sagebrush, and in many places this plant forms mixed
growths with snowbrush and Haplopappus. The low brush of this
association is formed by closely spaced bushes with grasses growing
between.

Because of its limited occurrence in the San Gabriel Mountains,
this association there has relatively little effect on mammalian distribution.
Locally, nevertheless, the presence of this association
governs the distribution of certain mammals. For example, on Blue
Ridge, islands of sagebrush amid the conifers provide suitable
habitat for Dipodomys agilis perplexus and Perognathus californicus
bernardinus; and in Swarthout Valley D. a. perplexus, Reithrodontomys
megalotis longicaudus, and Lepus californicus deserticola are
seemingly restricted to the sagebrush flats.

This association is on the piedmont that dips toward the Mojave
Desert from the interior base of the San Gabriels. The widely
spaced Joshua trees with low bushes between, and the dry washes
breaking the level terrain below the mouths of canyons are typical
of this area. Field work was extended no farther down into the
desert than about the 3500 foot level, where this association was still
dominant.

Although the vegetation of this area is scattered and sparse, presenting
a barren and sterile aspect, the area supports a rather high
population of rodents. The soil at the bases of many large box-thorn- and
creosote-bushes is perforated by burrow systems of
Dipodomys panamintinus or Dipodomys merriami, and those burrows
abandoned by kangaroo rats are used as retreats by Onychomys
torridus and Peromyscus maniculatus. The mammals of this associ[Pg 531]ation
are all characteristic of the fauna of the Mojave Desert, with
the ranges of such species as the coyote and jack rabbit extending
well up the desert slope of the mountains.

The mammals listed below were taken in 1948 in roughly 400
trap nights in the Joshua belt, at an elevation of 3500 feet, one mile
below the mouth of Graham Canyon.

Table 9.—Yield of 400 Trap-nights in the Joshua Tree Belt.

Populations of Dipodomys merriami and D. panamintinus fluctuate
widely, possibly in response to weather cycles. In November of
1948 trapping in the Joshua belt showed that panamintinus outnumbered
merriami approximately three to one, whereas in December
of 1951, after a succession of unusually dry years, merriami was the
more numerous. Further, merriami occurred in the lower parts of
the juniper belt in 1951 where in 1948 it seemed to be absent.

Dipodomys merriami merriami and Onychomys torridus pulcher
are diagnostic of the Joshua tree woodland association in the San
Gabriel Mountains area, since few individuals of either species occur
outside of this association.

Fig. 1. View of typical coastal sage scrub association, showing in foreground
white sage, and coastal sagebrush. The adobe banks beyond are
grown mainly to white sage. Small mammals are abundant in this association,
with Dipodomys agilis, Perognathus fallax, and Sylvilagus audubonii being
characteristic of the area. Photo March 25, 1952, at mouth of San Antonio
Canyon, 1800 feet elevation.

Fig. 2. View of a main channel in San Antonio Wash on Pacific slope. The
wash is a distinct habitat in the coastal sage scrub association, and is the
preferred habitat of Peromyscus eremicus fraterculus and Neotoma lepida
intermedia. These rodents find shelter in the piles of boulders. Photo February
2, 1952, in San Antonio Wash, at 1700 feet elevation.

Fig. 1. Southern oak woodland association. The open leaf-strewn floor of
the woodland lacks shelter for ground-dwelling rodents and the population of
rodents is small. Peromyscus boylii rowleyi is the commonest rodent. Photo
March 10, 1952, in Evey Canyon, 2700 feet elevation.

Fig. 2. Yellow pine forest association, composed largely of yellow pines,
white fir, and black oak. Photo April 27, 1952, at Big Pines, 6800 ft. elevation.

Fig. 1. View of the sagebrush scrub association showing a nearly pure
stand of basin sagebrush. Dipodomys agilis perplexus and Reithrodontomys
megalotis longicaudus occur in this association, and Peromyscus truei montipinoris
is present where this association merges with the pinyon-juniper association.
Photo April 27, 1952, in Swarthout Valley, 6200 feet elevation.

Fig. 2. View of a pinyon pine woodland. This habitat constitutes the
upper part of the pinyon-juniper association, and is the habitat of Neotoma
fuscipes simplex, Peromyscus truei montipinoris, and Eutamias merriami
merriami. Photo April 27, 1952, in Sheep Creek Canyon, 5500 feet elevation.

Fig. 1. View of the juniper belt. This habitat forms the lower part of the
pinyon-juniper association. Perognathus fallax pallidus, Dipodomys panamintinus
mohavensis, and Peromyscus truei montipinoris are typical of this
area. Photo April 27, 1952, at Desert Springs, 4300 feet elevation.

Fig. 2. Joshua tree woodland association. The characteristic mammals are
Dipodomys panamintinus mohavensis, D. merriami merriami, and Onychomys
torridus pulcher. Photo January 4, 1952, 6 miles east and 2 miles south Llano,
3600 feet elevation.

Accounts of Species

The opossum is common in and near small towns and cultivated
areas at the Pacific base of the mountain range and does not thrive
away from human habitation; extensive trapping in the coastal sage
and chaparral belts produced no specimens except immediately adjacent
to citrus groves. Pequegnat (1951:47) mentions that opossums
in the Santa Ana Mountains of southern California are in the
lower parts of the larger canyons, especially near human habitation.

Workings of moles were found on the Pacific slope of the mountains
from 1600 feet at Claremont up to 7500 feet on Blue Ridge,
and on the Pacific slope beneath basin sagebrush in Cajon Canyon
one mile from desert slope Joshua-tree flats, but not on the desert
slope, although moles probably occur on that slope in some of the
places where there is suitable habitat.

Near Camp Baldy in the sandy soil beneath groves of alders
moles seemed to be especially abundant. Although common on the
coastal face of the range, moles shunned compact, dry, or rocky
soils. In the greasewood chaparral one-half mile west of the mouth
of Palmer Canyon, where the soil was hard and rocky, mole tunnels
were in soft soil that had accumulated at the edge of a fire road beneath
a steep road cut. The assumption is that this accumulation
contained insects attractive, as food, to the moles.

Jackson (1928:124) recorded a specimen from Camp Baldy,
4200 feet, San Antonio Canyon.

Both of my specimens were taken amid riparian growth on the
Pacific slope of the range.

One was taken in 1946 beneath a woodpile on the campus of
Norton School, two miles northeast of Claremont, and examined
by Dr. W. E. Pequegnat.

A female was taken in lower San Antonio Canyon, 2800 feet elevation,
on September 27, 1951.

This species was observed and collected at several stations ranging
from 2800 feet elevation in San Antonio Canyon, to Blue Ridge
at 8200 feet, and down the desert slope to 6000 feet at Jackson Lake.
This distribution encompasses most of the chaparral and yellow
pine forest associations. Within these areas, however, this bat
shows marked habitat preferences.

Woodland habitats seem to be preferred by evotis. At several
ponds in lower San Antonio Canyon this bat was observed repeatedly
as it foraged over the water and coursed low between rows of
alders and Baccharis. At Blue Ridge in September, 1951, these
bats foraged approximately six feet above the ground beneath the
canopy of coniferous foliage and between the trunks of the trees.

Most of the bats were taken by stretching fine wires above the
surface of a pond as outlined by Borell (1937:478). Collecting was
generally carried on until at least 11:00 p. m., and the time at which
each bat was taken at the pond was recorded, thereby making possible
a rough estimate of the pre-midnight forage period of each
bat commonly collected at the ponds. Usually bats taken at the
start of their supposed forage period had empty or nearly empty
stomachs, whereas those taken towards the end of their forage
period had full or nearly full stomachs. M. evotis usually first appeared
just at dark, well after the pipistrelles and California myotis
had begun foraging. The forage period of evotis seemed to begin
approximately 30 minutes after sunset and to end approximately
two and one-quarter hours later.

Individuals of this species were taken from May 4, to October
14, 1951. A female taken on May 19, 1951, in San Antonio Canyon,
carried one minute embryo, and one taken in the same locality on
June 8, had one embryo four millimeters in length.

Although seldom found to be plentiful, this bat was recorded
from many points on both the coastal and desert slopes of the
mountains. Specimens were taken in the chaparral association in
San Antonio Canyon, near Jackson Lake among yellow pines, and
in Mescal Canyon at the upper limit of the Joshua tree woodland.
Bats, probably volans, were noted over sage flats at 8000 feet elevation
on Blue Ridge. The only place where these bats appeared to
be numerous was Jackson Lake on the interior slope; there, on September
19, 1951, volans appeared with the pipistrelles, and was the
most common bat before dark.

An individual of this species taken on October 28, 1951, in a
short mine-shaft in the pinyon belt at the head of Grandview
Canyon was slow in its movements and felt as cold as the walls
of the tunnel. It was late afternoon and the temperature outside the
cave was below 40°F. The floor of the tunnel was covered with
the hind wings of large moths of the genus Catocala; volans probably
hung in the cave while eating them.

The series of volans from the San Gabriels shows that the two
color phases of this bat both occur in the area. Two specimens from
Jackson Lake contrast sharply with the rest of the series in their
dark coloration. Benson (1949:50) states that color variation in a
series of volans from a given locality may be striking.

This bat was collected in San Antonio Canyon from 50 minutes
after sundown to two hours and 40 minutes after sundown. In this
area these bats did not visit the ponds in large numbers as they
seemed to do on the desert slope.

A female taken on May 29, 1951, contained one embryo nearly
at term.

On the Pacific face of the mountain range this bat was recorded
commonly below approximately 5000 feet elevation, where it seemed
to be most common in the oak woodland of canyons. On the desert
slope it was collected at Jackson Lake in yellow pine woodland, in
Mescal Canyon in the juniper belt, and bats presumably of this[Pg 535]
species were observed at several points in the pinyon-juniper
woodland.

Individuals of this species were often observed foraging from
five to ten feet above the ground around the alders and Baccharis
near San Antonio Creek, but they did not fly so low or so near the
vegetation as did Myotis evotis. Here they were taken from 18
minutes to 55 minutes after sunset; this indicates an early and short
forage period.

This bat may be active even in winter. On February 8, 1952, in
lower San Antonio Canyon, a bat, probably of this species, was noted
foraging; and collecting in early November, 1951, yielded specimens.

On May 22, 1951, a female obtained in San Antonio Canyon had
one five-millimeter embryo, and subsequently all the females examined
had embryos until June 12, when collecting was discontinued.

This is the most obvious if not the most common bat of the lower
coastal slopes of the San Gabriels. In the spring and fall of 1951
individuals were noted from 1700 feet in the coastal sage scrub association
to the white fir forests on Blue Ridge at 8200 feet elevation
and were commonest in the rocky canyons of the lower Pacific slope
below 4000 feet, and usually foraged near the steep canyon sides
high above the canyon bottoms.

Pipistrelles were generally the first bats to appear in the evening,
although the times of their appearance were irregular. In April
and May, in lower San Antonio Canyon, they appeared from 28
minutes before sunset to 30 minutes after sunset, with the average
time of appearance eight and one-half minutes after sunset. Like
Myotis californicus this pipistrelle seemed to have a short and early
foraging period. No pipistrelles were recorded at ponds later than
one hour and five minutes after sunset, and usually they were not
seen later than 40 minutes after sunset. Most of the specimens taken
later than one half hour after sunset had full stomachs. More
than 50 pipistrelles were captured at the ponds in San Antonio
Canyon; six were kept for specimens. This species is probably
present in the area throughout the winter. Pipistrelles were active[Pg 536]
in early April in Evey Canyon, were observed in early November
in San Antonio Canyon, and on January 26, 1952, an individual was
noted foraging near the mouth of Palmer Canyon. They are probably
not active in winter on the colder desert slope of the mountains.

Pipistrelles often foraged in loose flocks of about half a dozen
individuals. On many occasions these groups were first seen foraging
high up above the canyon bottom, then, as it grew darker, they
descended and foraged within 50 or 100 feet of the floor of the
canyon. Immediately before dark these groups seemed to have
forage beats; one minute several pipistrelles would be overhead,
and the next minute none would be in sight.

A female taken in San Antonio Canyon on June 8, 1951, contained
two five-millimeter embryos.

This species was common in the spring and autumn of 1951 from
the lower edge of the yellow pine forest down into the belt of Joshua
trees. In early April on the desert slope at 4800 feet in Mescal
Canyon, pipistrelles foraged on evenings when it was windy but
not cold. On cold evenings (when the temperature was below
roughly 45°F) none was seen. On windy nights the pipistrelles
often forsook their usual high forage habits and foraged 15 feet
or so above the ground where the vegetation and outcrops of rock
broke the force of the wind. In 1951 no pipistrelles were noted on
the desert slope later than October 15.

This bat was on the coastal slope from the sage scrub association
at 1100 feet, up to 8000 feet on Blue Ridge, and on the desert slope
down to the upper edge of the Joshua tree belt at 4800 feet in
Mescal Canyon. It was the most common bat at the ponds in San
Antonio Canyon in May and June of 1951, but in September and
October of the same year none was obtained there.

On the Pacific slope of the San Gabriels the big brown bats segregate
according to sex in the spring, the males occupying the foothills
and mountains and the females the level valley floor at the coastal[Pg 537]
base of the range. Of 70 big brown bats captured in May and
June of 1951, at the ponds in San Antonio Canyon, only one was a
female. A large colony of more than 200 individuals in a barn near
Covina, in the citrus belt, was composed of only females.

Times of capture of this bat at the ponds in San Antonio Canyon
ranged from ten minutes after sunset to two hours and thirty minutes
after sunset. Generally these bats came to the ponds in groups
of several individuals, and often more than a dozen were captured
in the course of an evening's collecting.

One female was taken on September 30, 1951, in San Antonio
Canyon, at 2800 feet elevation. The descriptions which the citrus
growers of the Claremont and Glendora vicinity give of the bats
they find occasionally hanging in their citrus trees accurately describe
this species. Its seasonal occurrence there is unknown.

Specimens were collected in spring in 1951 at elevations of 2800
and 3200 feet in San Antonio Canyon, on the coastal slope, and in
Mescal Canyon at 4900 feet, on the desert slope. Large, fast flying
bats, probably of this species, were seen at Jackson Lake, 6000 feet
elevation, on October 15, 1951.

Hoary bats are present in the San Gabriels in the fall, winter, and
spring. In 1951 the last spring specimen was taken on June 11,
in Mescal Canyon; then collecting was discontinued until late September
when the first hoary bat was taken on the thirtieth of that
month. From this date on into the winter hoary bats were recorded
regularly. They seemed to be as common in early June as in most
of April and May; possibly some remain in the San Gabriels throughout
the summer.

In spring these bats seem to segregate by sex; of twelve kept as
specimens and at least an equal number captured and released only
one was a female. All were captured above 2800 feet.

Hoary bats seem to have a long pre-midnight forage period, having
been captured at ponds from 21 minutes after sunset, to three hours
and 26 minutes after sunset. Generally those taken early had empty[Pg 538]
stomachs and those taken later had full stomachs. On the night of
May 24, 1951, a hoary bat captured two hours and five minutes
after sunset had only a partially full stomach.

On May 25, 1951, an unusual concentration of hoary bats was
observed at a pond at about 3200 feet elevation, in San Antonio
Canyon (Vaughan, 1953). The day had been clear and warm, one
of the first summerlike days of spring. Beginning at 30 minutes
after sundown hoary bats were collected until two hours and 35
minutes after sundown; in this period 22 were caught and at least
as many more observed. Many were released after being examined,
whereupon they hung on the foliage of nearby alders to rest and
dry themselves. This concentration of hoary bats may have been
due to a sudden beginning of migration with a resultant concentration
of bats at certain altitudinal belts. The warm weather might
have set off the migration. On evenings that followed subsequent
hot days no such concentration of hoary bats was seen. B. P. Bole
(Hall 1946:156) observed a concentration of hoary bats on August
28, 1932, in Esmeralda County, Nevada.

Several captive Myotis californicus in a jar next to a pond in San
Antonio Canyon set up a squeaking which seemed to attract a hoary
bat. Repeatedly the large bat swooped over the jar.

The pallid bat is probably the most common and characteristic
bat of the citrus belt at the Pacific base of the mountains. Only
once, on May 4, 1951, was this bat taken in the mountains. On
that night two individuals were collected at 2800 feet in San Antonio
Canyon. All of the other specimens and observations were from
colonies in old barns and outbuildings in the citrus belt where these
bats are found in spring, summer, and fall.

The impression gained by examining many mixed colonies of
Antrozous and Tadarida was that the former greatly outnumbered
the latter. For example, a small colony of bats in an old barn near
San Dimas Wash consisted of about thirty pallid bats and five freetails.

Large numbers of wings of moths of the family Sphingidae, and
legs and parts of the heads of Jerusalem crickets (Stenopelmatus
fuscus)[Pg 539]
were beneath an Antrozous night-roosting place in a barn
near Upland.

Pallid bats were collected in 1951, from April 16 to October 17
but probably were active in the area into November.

Each of two pregnant females taken two miles northeast of San
Dimas on April 20, 1951, carried two embryos 4 millimeters long.

This bat, regularly met with in the citrus belt at the coastal base of
the range, occurred in small numbers with colonies of Antrozous,
and was once found with a colony of Eptesicus near Covina. None
of the females taken in April 1951 was pregnant.

H. W. Grinnell (1918:373) mentioned individuals collected at
Sierra Madre (at the coastal base of the San Gabriels west of the
study area), and Sanborn (1932:351) reported specimens from
Covina and Azusa. Probably this bat occurs locally all along the
coastal base of the range.

This species was found in the coastal sage belt from Cajon Wash
west to San Gabriel Canyon and was most plentiful in thin stands
of sagebrush, and in and around citrus groves. Because of their
preference for semi-open country, jack rabbits are absent from
much of the coastal belt of sagebrush where the brush is fairly
continuous, and they never were observed in the chaparral association.

Coyotes catch many jack rabbits and regularly forage around the
foothill borders of the citrus groves for cottontails and jack rabbits.

A female examined on February 19, 1951, was pregnant, and one
taken on March 15, 1951, carried three small embryos.

There was sign of jack rabbits along the desert slope of the San
Gabriels up to about 6700 feet, one-half mile west of Big Pines.
They were fairly common in the Joshua tree belt, occurred less
commonly in the juniper belt, and were present locally in small
numbers in the pinyon-juniper association.

The population seemed to be at a low ebb from 1948 to 1952,
when field work was done on the desert slope. I often hiked for
an hour or more on the desert or juniper-covered benches without
seeing a jack rabbit. The species was commoner in washes where
as many as eleven were noted in two hours' hiking.

In December, 1951, below Graham Canyon, the leaves on large
areas of many nearly recumbent Joshua trees had been gnawed down
to their bases, and jack rabbit feces covered the ground next to these
gnawings. Probably the Joshua tree is an emergency food used by
the rabbits only when other food is scarce.

In years when the population of jack rabbits is not low they serve
as a major food for coyotes. In the Joshua tree belt below Mescal
Canyon, jack rabbit remains were fairly common in coyote feces,
and tracks repeatedly showed where some coyote had pursued a
jack rabbit for a short distance. A large male bobcat trapped in
the juniper belt in Graham Canyon had deer hair and jack rabbit
remains in its stomach.

Cottontails are common in the coastal sage scrub association and in
and around citrus groves, but generally penetrate the mountains
no farther than the lower limit of the chaparral association. They
are everywhere on coastal alluvial slopes, except in the barren
washes, and prefer patches of prickly-pear and often are loathe to
leave its protection. After completely destroying a large patch of
prickly-pear in the course of examining a wood rat house in the
center of the cactus, I found hiding, in the main nest chamber of the
house, a cottontail that dashed from its hiding place only when
poked forceably with the handle of a hoe.

Cottontails are seldom above the sage belt in the chaparral associations,
although along firebreaks and roads they occasionally
occur there. Habitually cottontails escape predators in partly open[Pg 541]
terrain offering retreats such as low, thick brush, rock piles, and
cactus patches; but on open ground beneath dense chaparral, cottontails
may be vulnerable to predation.

Examinations of feces and stomach contents of the coyote reveals
that it preys more heavily on cottontails than on any other wild
species. Remains of several cottontails eaten by raptors were found
in the sage belt.

In April, 1951, many young cottontails were found dead on roads
in the sage belt, and a newly born cottontail was in the stomach of
a coyote trapped four miles north of Claremont, on February 7, 1952.

This subspecies was recorded on the interior slope from 5200 feet
elevation, as at the head of Grandview Canyon, down into the
desert, and was common in the sagebrush flats of the upper pinyon-juniper
association. Piles of feces under thick oak and mountain-mahogany
chaparral indicated that the rabbits often sought shelter
there. Adequate cover is a requirement for this rabbit on the
desert slope of the San Gabriels; in the juniper and Joshua tree
belts the species occurs in washes where there is fairly heavy
brush, and only occasionally elsewhere. In the foothills, when
frightened from cover in one small wash cottontails often run up
over an adjacent low ridge and seek cover in the brush of the next
wash. In the wash below Graham Canyon tracks and observations
showed that cottontails were taking refuge in deserted burrows of
kit foxes.

In the pinyon-juniper association cottontails and jack rabbits probably
occur in roughly equal numbers, but in the Joshua tree belt
cottontails seem far less numerous than jack rabbits. In the course
of a two hour hike in lower Mescal Wash, at about 3500 feet, eleven
jack rabbits and two cottontails were noted.

Brush rabbits inhabit the Pacific slope of the mountains from
about 1200 feet in the coastal sagebrush belt up to at least 4500
feet in the chaparral, and are the only lagomorphs found commonly
[Pg 542]
above the lower edge of the chaparral association. Here they were
often on steep slopes beneath extensive and nearly impenetrable
tracts of chaparral.

The ecologic niche of the brush rabbit is in brush where the
plants form continuous thickets with little open ground. In the
coastal sagebrush flats, areas supporting only scattered bushes are
uninhabited by brush rabbits, while areas grown to extensive tracts
of brush harbor them. When the brush rabbit's mode of escape
from its enemies is considered, the reason for their habitat preference
becomes more clear. Almost invariably these rabbits seek
escape by running through the densest portions of the brush, never
appearing in the open; in this way they travel quickly away from
the source of danger without being observed. Because they avoid
being seen in the open, and do not seek safety largely through
running ability, they need continuous stretches of brush for escape.
While hunting in the coastal sagebrush belt I have repeatedly seen
frightened brush rabbits turn and dart beneath the bushes a few
feet from a human being rather than be driven into the open.

A great horned owl shot in March, 1951, in the sage belt, had
in its stomach the remains of a freshly killed adult brush rabbit.
Although coyotes and brush rabbits often occur in the same general
sections of the sage flats, remains of these rabbits have been notably
scarce in coyote feces from these areas. This is probably because
the coyote hunts along clearings and in open brushland, precisely
the type of habitat avoided by brush rabbits.

Gray squirrels were on both slopes of the San Gabriels in oak
woodland. A gray squirrel was observed in April of 1948, as it
climbed a telephone pole adjacent to an orange grove near Cucamonga.
This, and one noted bounding up a slope of greasewood
chaparral near Cattle Canyon, were the only gray squirrels seen
in areas which were not grown to oaks or adjacent to oak woodland.
In the lower foothills gray squirrels were invariably found in association
with valley oak, this plant forming limited woodland areas
in canyon bottoms. In the upper chaparral association the squirrels
frequented the large scrub oaks growing on talus slopes and canyon
sides. In the yellow pine woodland, gray squirrels are restricted
to black oaks, often where they formed mixed stands with the coni[Pg 543]fers.
On the interior slope these squirrels were found only at the
lower edge of the yellow pine woodland where black oaks are
common. There, in the vicinity of Big Pines, they were present
between roughly 5800 and 7000 feet, while on the Pacific slope they
inhabited oak woodland from 1600 feet to about 7000 feet elevation.

In Live Oak Canyon in December of 1950, tracks indicated that
a bobcat had killed a gray squirrel in a small draw beneath the oaks.
In Evey Canyon on March 6, 1951, while watching for bats at late
twilight, I observed a gray squirrel traveling through the branches
of a nearby oak. A great horned owl glided into the oak in an
attempt to catch the squirrel, which leaped quickly into a dense
mass of foliage and escaped. For roughly ten minutes the owl
perched in the oak watching its intended prey, then flew off down
the canyon amid frantic scolding by the squirrel.

On March 17, 1951, a female gray squirrel taken at about 3500 feet
elevation in San Antonio Canyon contained two embryos, each
roughly 40 millimeters long.

From the coastal sage belt, into the yellow pine forest of the
Pacific slope, this species is common on land cleared by man or
disturbed in the course of construction, or on severely eroded
slopes where the original climax vegetation is partly or completely
absent. Thus in the sage belt, ground squirrels live along dirt roads
through the brush, on the heavily eroded banks often found in
the foothills, on land grazed closely by sheep, and in those parts
of major washes such as San Antonio and Cucamonga washes
where scatterings of huge boulders offer prominent vantage points.
In San Antonio Canyon Spermophilus was restricted to the vicinity
of roads and firebreaks, and an especially large colony of at least
forty individuals lived at a dump one mile southwest of Camp Baldy
at about 4500 feet elevation. Ground squirrels used burned stems
of large laurel sumac as observation posts. Because of a preference
for open areas offering unobstructed outlooks, ground squirrels
originally probably did not penetrate the main belt of heavy chaparral
on the Pacific slope of the range except in some of the large
washes.

In the spring of 1951 and the preceding summer there was a
marked increase in the ground squirrel population near Padua Hills[Pg 544]
as a result of sheep grazing on approximately one-half square mile
of sage land. Grasses and smaller shrubs were eaten down to the
ground, and in some places coastal sagebrush and Haplopappus
were killed by browsing and trampling. The area formerly had a
sparse growth of bushes with intervening growths of tall grasses
and one colony of perhaps 20 ground squirrels; but after the sheep
grazing the area was open brushland with large clear spaces on
which the herbage was trimmed to the ground, and had at least four
colonies of ground squirrels as large as the first. Also there were
other ground squirrels established in various parts of the area.
Probably the dry weather in the winter of 1950-51 with consequent
retardation of the vegetation aided the spread of the squirrels in
this area.

In the sage belt, most ground squirrels are dormant by December.
In 1951, after a mild winter, squirrels were noted on January 25
near Padua Hills. On February 8, 1951, males in breeding condition
were collected, and on March 16, a female taken near San Antonio
Wash carried three small embryos. In early March of 1951, ground
squirrels were active at 4500 feet elevation in San Antonio Canyon.

This ground squirrel inhabited the desert slope of the mountains
up to 5000 feet elevation, and was most common in the juniper belt;
burrows often were made under large junipers. In May, 1949,
ground squirrels were common in the rocks adjacent to Mescal Wash
at an elevation of 4500 feet. In an apple orchard near Valyermo,
squirrels fed on the fallen fruit in early November of 1951.

No squirrel was seen in December, January, and February, indicating
that all were below ground in winter.

Antelope ground squirrels were common in the Joshua tree
woodland where they were noted up to 4500 feet elevation in
Graham Canyon. None was found on the pinyon slopes, possibly
because of the competition offered there by Eutamias merriami,
or because the rocky nature of the soil there rendered burrowing
difficult.

[Pg 545]

Although observed less often in winter than in summer, this
species is active all year. On February 6, 1949, in Mescal Wash,
an antelope ground squirrel was foraging over the snow which
was at least six inches deep. These squirrels were attracted to the
carcasses of rodents used as bait for carnivore sets, and caused a
good deal of trouble by disturbing the traps.

Antelope ground squirrels used the topmost twigs of box-thorn
bushes extensively as lookout posts, and many of their burrows were
at the bases of these thorny bushes. This habit of regularly using
observation posts is well developed in each species of ground
squirrel found in the San Gabriels.

This chipmunk was characteristic of the most boreal parts of the
San Gabriel Mountains. It was recorded from 6800 feet elevation at
Big Pines, to an altitude of approximately 9800 feet near Mt. San
Antonio, and was common where coniferous timber was interspersed
with snowbrush chaparral. In upper Icehouse Canyon and near
Telegraph Peak these chipmunks were associated with lodgepole
pines and chinquapin, and one mile east of Mt. San Antonio individuals
were often observed in thickets of manzanita. This chipmunk
usually shunned pure stands of coniferous timber except as
temporary forage ground.

On Blue Ridge these chipmunks used the uppermost stems of
snowbrush as vantage points, and when disturbed ran nimbly over
thorny surfaces of the brush in seeking refuge in the tangled growth.

In early November of 1951, these animals were not yet in hibernation
on Blue Ridge. They were noted on November 6, after the
season's first snows had melted; on November 13, however, a cold
wind with drifting fog kept most of them under cover, and only two
were noted in the course of the day.

The lower limit of the range of this species, on the coastal face of
the range, is roughly coincident with that of manzanita—that is to
say, it begins in the main belt of chaparral above the lower foothills.[Pg 546]
E. merriami seems to reach maximum abundance amid the granite
talus, and scrub oak and Pseudotsuga growth at the upper edge of
the chaparral association. It was absent, however, from all but the
lower fringe of the yellow pine forest association.

On the desert slope merriami was partial to rocky areas in the
pinyon-juniper association but was also in the black oak woods on
the Ball Flat fire road near Jackson Lake. Nowhere was Eutamias
merriami and E. speciosus observed on common ground.

No specimens of this species were taken in the field work in
the San Gabriels, nor did I find any rangers or residents of the
mountains who had seen flying squirrels in the area. Nevertheless
sign found in the white fir forests in the Big Pines area indicated
that flying squirrels may occur there. On a number of occasions
dissected pine cones were noted on the horizontal limbs and bent
trunks of white firs. These cones were too large to have been
carried there by chipmunks, and gray squirrels were often completely
absent from the areas. I suspect that extensive trapping in
the coniferous forests of the higher parts of the mountains would
produce specimens of flying squirrels. Willett (1944:19) mentions
that flying squirrels probably occur in the San Gabriel Mountains.

This gopher was found below about 5000 feet elevation in disturbed
or open areas from Cajon Wash at Devore westward all
along the coastal base of the San Gabriel Range. In the lower
part of the chaparral belt the gopher evidently was absent from
the chaparral-covered slopes, but was common along roads and
on fire trails.

Burt (1932) and von Bloeker (1932) discuss the distribution
of the three subspecies of this species, pallescens, neglecta, and
mohavensis, which are in the San Gabriel Mountains area, and
Burt indicates that pallescens grades toward mohavensis in the
southern part of Antelope Valley.

In the forests of yellow pine and white fir of the higher parts of
the San Gabriel Mountains the workings of this gopher were common,
and sign of its presence was found above 4500 feet on both
slopes of the mountain range. The rocky character of the coastal
slope seems to limit the occurrence of gophers, for they are not
continuously distributed there. On the desert slope they occur locally
down into the pinyon-juniper belt.

In the vicinity of Big Pines, on the interior slope, these gophers
preferred broken forest where snow brush or other brush occurred;
their workings, however, were also found beneath groves of conifers
and black oaks. The abundance of earth cores resting on the duff
indicated that this species is active in the snow in winter.

One specimen of this subspecies was taken on December 31, 1951,
in the Joshua tree belt, eight miles east of Llano, 3700 feet elevation.

This pocket mouse is restricted to the coastal sage scrub association,
and was recorded from Cajon Wash west to Live Oak Canyon.
The mouse does not inhabit even the lower edge of the chaparral
belt, but in the coastal sage flats is usually the most abundant rodent.
In disturbed parts of the coastal sage belt fallax is less common, and
was never trapped in channels of rocky washes. Trap lines in the
eroded adobe banks of the foothills, where white sage and coastal
sagebrush are the dominant plants, took mostly these pocket mice.
Although the soil of such slopes is compact and seemingly is unsuitable
for burrowing by heteromyids, fallax is the most common
rodent. Because few burrows of pocket mice were noted there, it
is possible that the many old unused burrows of Spermophilus and
Dipodomys which honeycomb certain parts of adobe banks are[Pg 548]
used also by fallax; some of these burrows shelter Peromyscus
eremicus and Peromyscus californicus.

These mice are inactive above ground in cold weather. In the
sage belt near Thompson Canyon, where this subspecies had been
found to be the most common rodent, none was trapped on the
sub-freezing night of December 3, 1948, although other rodents
were found in usual numbers. Individuals have been taken on
nights of intermittent rain, yet none has been trapped on freezing
nights.

This species is characteristically heavily infested by a large species
of mite. Usually these mites congregate around the base of the
tail.

On October 11, 1949, one lactating female and two carrying
embryos were taken.

On the desert slope of the mountains this species is found in the
part of the pinyon-juniper association that is between elevations of
4000 and 5200 feet. The mouse is absent from the higher chaparral
and pinyon-covered slopes, but is present on south slopes in the
pinyon belt where more open growths of pinyons and scrub oaks
are interspersed with yucca. I recorded this pocket mouse from the
vicinity of Cajon Pass west to Valyermo.

The local distribution of pallidus is striking because of its close
positive correlation with the distribution of yucca. On benches
around 5000 feet, where yuccas are scattered in their occurrence,
pallidus is nearly always taken near (often right at the base of)
this plant. Lower in the juniper belt the dry rocky south slopes
supporting yucca plants are well populated by pallidus, while adjacent
flats, and north slopes grown to antelope brush and scrub oak,
are completely uninhabited. Near the mouth of Grandview Canyon,
on steep rocky southern exposures grown sparsely to burro weed and
yucca, one hundred traps produced in one night eight pallidus and
no other rodents. Here many of these pocket mice were trapped
on large fractured rock outcroppings, where most or all of the mice
probably lived in the daytime in the deep cracks; in any event no
burrows were noted near these rocks.

[Pg 549]

This species prefers barren slopes supporting yucca plants.
These plants produce large seeds which are staple food items for
P. f. pallidus and other rodents during the lean part of the year,
that is to say, late summer and autumn. Many of the dry capsules
of the yucca plants were examined in October, 1951, and these
generally still contained a few seeds. Pocket mice taken in October
usually carried in their cheek pouches seeds of yucca together with
some other material, and often they carried only the seeds of yucca.
Probably the wind shakes only a few seeds out of the capsules at a
time, thus tending to drop the seeds over a fairly long period.

Trapping in winter in the juniper belt revealed that these pocket
mice were not active above ground on nights colder than about
40° F. On nights when the temperature was about 36° F. none was
taken, but on the one night in late December, 1948, when the minimum
was 44° F., several specimens were taken. In this same area
in May 1949, pocket mice were the most numerous rodents. Because
of their evident sensitivity to cold weather, these mice must remain
below ground for weeks at a time during the cold weather of
December and January.

Specimens of pallidus from the desert slope of the San Gabriels
are grayer (less brown) than specimens taken farther southeast in
the Mojave and Colorado deserts. Further sampling of populations
of Perognathus fallax from areas adjacent to the San Gabriels might
demonstrate differences of sufficient magnitude to warrant subspecific
distinction of the San Gabriel population. Possibly, however,
the San Gabriel series manifests only local variation in the
race pallidus. Grinnell (1933:54) characterizes the ecological niche
of the race pallidus as being "open, sandy ground, often ...
surrounded by rocky slopes," whereas these pocket mice in the
San Gabriels inhabited gravelly or rocky juniper-dotted benches.

Mice of this subspecies were recorded from the lower chaparral
association below about 4000 feet elevation along the coastal face
of the San Gabriel Range. They were trapped on greasewood-covered
slopes, in mixed growths of white sage and buckwheat, and[Pg 550]
beneath scrub oak and lilac chaparral; however none was taken in
the heavy chaparral of the upper parts of the chaparral association.

One small juvenile in gray pelage was taken in San Antonio
Canyon on October 1, 1951.

On Blue Ridge these mice were recorded between 7100 and 8000
feet elevation. Here they were restricted to dense tracts of snowbrush
and sagebrush, often where these tracts were interspersed
with, or beneath, open groves of conifers. These mice seemed to
favor areas where this thick brush was broken by patches of open,
grass-covered ground. Benson (1930:450) records this subspecies
from Swarthout Valley, near Big Pines, at 6860 feet elevation.

While setting traps for pocket gophers one mile southwest of
Big Pines, in September of 1951, I frightened a pocket mouse from
its burrow. The animal jumped into the tangle of interlacing twigs
of a nearby clump of snowbrush, and with great dexterity climbed
into the center of the bush, where it was lost to view. I was
surprised at the facility with which this saltatorial rodent traveled
through the network of small branches.

In winter, in areas inhabited by this mouse, snow covers the
ground for long periods during which these mice are probably
forced to remain below ground.

This rat is common in the Joshua tree and juniper belts, and
locally penetrates the pinyon belt at about 5000 feet elevation.
It occurs regularly along the entire desert slope of the San Gabriel
Mountains.

The upper limit of the range of this species roughly coincides
with the upper limit of the juniper belt, and within this range it
was found to inhabit areas having widely different soil types. It
occurred on the sandy ground of desert washes, the gravelly soil of
the juniper-clad benches, and the mixed sandy and rocky ground of[Pg 551]
washes in canyons. A preference is shown by panamintinus for fairly
level ground. Rough terrain or steep slopes are generally avoided,
whereas rather large colonies of these kangaroo rats are found in
small flats of the desert foothills.

Below about 4500 elevation on the interior slope this species was
the most numerous rodent, and seemed to reach maximum abundance
in the Joshua tree association. About 500 trap-nights in the
juniper belt near Graham Canyon yielded 31 specimens, whereas
about 300 trap-nights in Joshua tree flats took 34 individuals.

The cheek pouches of many specimens taken in early winter
contained green shoots of grass and little dry material. On many
occasions rat traps set next to wood rat nests beneath large junipers
produced panamintinus, and many of these animals had their cheek
pouches crammed full of juniper berries.

In December, 1948, panamintinus was trapped consistently on
nights when the temperature dropped to below 20° F. On December
27, 1948, after a three inch snowfall, tracks of this species were
noted in the snow at the mouth of Mescal Canyon.

Parts of the skulls of this species were found in many coyote
feces from the desert slope.

This kangaroo rat barely enters the area under consideration
and is almost restricted to the Joshua tree association, for only a
few individuals were taken at the lower edge of the juniper benches.
This species inhabits the Joshua tree belt all along the desert base
of the San Gabriels.

As mentioned in the description of the Joshua tree association,
the relative numbers of Dipodomys merriami and D. panamintinus
shifted from 1948 to 1951, possibly concurrent with the seasons of
low rainfall in this period. Whereas in 1948 merriami was decidedly
less abundant than panamintinus in the Joshua tree belt, in
1951 the numbers were reversed.

In December, 1951, it was found by tending the traps in the
early evening that merriami foraged fairly early before the ground
had frozen solidly.

One specimen of this subspecies was trapped on November 26,
1951, in a sandy channel of Cajon Wash near Devore beneath a
clump of scale-broom.

This species was found below about 4000 feet elevation all along
the coastal face of the range and reached maximum abundance
in the level tracts of coastal sage. It was one of the most abundant
rodents there, usually being second to Perognathus fallax in point
of numbers. Large colonies of kangaroo rats occurred locally on
sandy ground adjacent to large washes. The rats were found
sparingly on the foothill adobe banks and in the greasewood
chaparral of the lower foothills, but in heavy chaparral where a
layer of plant debris covered the ground, such as on north slopes
grown to scrub oak and lilac, kangaroo rats were completely absent.
Thus, in the lower chaparral belt, this rodent had a discontinuous
distribution.

The coyote probably is one of the major predators of these
kangaroo rats; remains of this rodent were often found in coyote
feces, and coyotes excavated many burrow systems in large kangaroo
rat colonies in the sandy ground near San Antonio Wash. The soil
there is so soft that coyotes probably were often successful in
digging out their prey. The shed skin of a large Pacific rattlesnake
(Crotalus viridis helleri) was found four feet inside the mouth of
a kangaroo rat burrow; probably this reptile preys on agilis. Great
horned owls (Bubo virginianus pacificus) come down nightly from
the chaparral to hunt in the sage flats. Beneath the perches of
these owls I have found pellets containing bones of agilis.

All the specimens of this species from the desert slope of the
San Gabriel Range are referred to the subspecies perplexus. They
were taken in brushy habitats between the elevations of 4500 and
7400 feet. Throughout much of this area perplexus was found only
in certain restricted areas more or less surrounded by inhospitable[Pg 553]
ground. For example, at 7400 feet on Blue Ridge, they were
found occasionally in the strips of sagebrush and lilac brush which
locally capped this ridge. Often these patches of chaparral on
Blue Ridge were surrounded by areas unsuitable for kangaroo rats:
on the Pacific slope, talus, oaks, and yellow pines prevailed; on
the ridge scattered yellow pine groves were present; and on the
steep desert slope there were yellow pines and white firs. In
Swarthout Valley perplexus was found in flats that supported basin
sagebrush and Haploppus, while the coniferous forests to the south,
and pinyon-covered slopes to the north were uninhabited. On flats
supporting antelope brush and juniper, perplexus was often common,
but it did not penetrate the chaparral of adjacent slopes
grown to scrub oak and mountain-mahogany. In general then,
perplexus was found in fairly open brushy flats or slopes, even
where these were surrounded by unsuitable habitats.

Specimens of D. agilis from the desert slope two miles east of
Valyermo are referrable to the subspecies perplexus. A series taken
in Cajon Wash at Devore, on the Pacific slope, is intermediate between
agilis, of the coastal slope of the San Gabriels, and perplexus
of the desert slope, but approaches more nearly the later subspecies.
Thus, different subspecies of D. agilis occur on opposite
slopes of the San Gabriel Mountains, with intergradation taking
place in the Cajon Pass area and probably also at the west end of the
Mountains.

Both scrub oak acorns and juniper berries were found in the
cheek pouches of this subspecies, and one immature individual
taken in Swarthout Valley had its cheek pouches stuffed with approximately
550 seeds of brome grass.

On November 13, 1951, at 7500 feet on Blue Ridge, a small juvenile
was taken; it must have been born not earlier than September.

This species inhabited grassy areas of the coastal sage belt, and
reached maximum abundance on cleared land grown thickly to
weeds and scattered brush. The mouse was only locally abundant—being
scarce throughout much of the sage belt—but was found[Pg 554]
under contrasting conditions. In San Antonio Wash the species was
taken among rocks and sparse weeds, at Palmer Canyon specimens
were trapped on a barren ridge sparsely clothed with greasewood
and white sage, and also one mile E of Big Pines in flats supporting
basin sagebrush and a fairly dense growth of grasses. The western
harvest mouse was recorded from 1500 feet elevation to 3200 feet
on the Pacific slope, and at 6600 feet near Big Pines on the desert
slope.

Those specimens of harvest mice from near Big Pines may be
grading toward the desert race megalotis; my series of specimens
from this locality, however, is too small for clear indications on this
point.

Individuals in juvenal pelage were taken on November 26, 1951,
near Devore.

In Mescal Wash on the desert slope of the San Gabriels, this
mouse was one of the most abundant mammals and was the only
rodent other than Peromyscus maniculatus regularly trapped in the
barren channels of washes. In Mescal Wash, at an altitude of 4000
feet, eremicus occurred along with the chaparral-inhabiting Peromyscus
boylii and Peromyscus californicus. The two species last
mentioned were associated with the occasional large patches of
manzanita, antelope brush, and other brush of the wash, whereas
eremicus was trapped in the rocky and sandy channels among scattered
bushes of scale-broom. No specimens of eremicus were taken
on the juniper-clad benches adjacent to the wash.

This mouse was recorded from 1900 feet elevation, one mile south
of the mouth of San Antonio Canyon, to 3200 feet elevation in Cajon
Canyon. This subspecies is characteristic of the sage belt and shows
a strong preference for the rough rocky areas found in dry washes.
Although in many areas the channels of the washes are immediately
adjacent to sandy sagebrush-covered flats, eremicus is not common
in the latter areas. Rocks seem to be essential to eremicus, for sandy[Pg 555]
areas in the sageland which were devoid of rocks yielded only an
occasional specimen. For example, 100 trap-nights in the main
channel of San Antonio Wash yielded 23 eremicus and only six
other rodents; while in the sandy sage areas nearby 200 trap-nights
yielded only one eremicus and 32 other rodents.

In lower San Antonio Canyon eremicus seemed restricted to the
rocky canyon bottom, none having been trapped on the steep slopes
nearby. This subspecies occurs commonly, however, on the adobe
banks grown to white sage at the base of the foothills. There eremicus
occurred on common ground with Perognathus fallax fallax,
and was often the only Peromyscus taken.

This species may be restricted by temperature; washes above
4000 feet elevation, which seemed suitable were uninhabited by
these mice.

On December 1, 1949, two females taken at the mouth of Palmer
Canyon had well advanced embryos. A female trapped in San
Antonio Canyon on September 19, 1951, was lactating. Juveniles
were caught in the sage belt in October, 1951.

This mouse inhabits areas supporting chaparral on the coastal
slope of the San Gabriels below 5000 feet. In the chaparral it is
usually the most plentiful rodent, being dominant on slopes which
have been burned over and on which greasewood chaparral has
taken over. On one such slope at the head of Cow Canyon, at 4500
feet, this was the only rodent trapped, although an occasional wood
rat house was noted. Trapping records gave the impression that
this form was the most ubiquitous rodent in the entire chaparral
belt. Nearly every trap line, even in such non-productive areas as
oak woodland, took the California mouse; and in many areas, as in
thick lilac brush, this mouse was by far the most abundant rodent.
Specimens were taken on the damp ground next to San Antonio
Creek, and in the riparian growth. In San Antonio Wash the California
mouse was found in thickets of laurel sumac and lemonade
berry, or other large shrubs, but were absent from most of the adjacent
sageland. The one place where they were found away from
heavy brush was on a series of barren adobe banks, near Palmer
Canyon, clothed mostly with white sage. Here they found shelter
in the unused burrows of kangaroo rats and ground squirrels.

[Pg 556]

The only place on the desert slope where this species was taken
was in Mescal Wash. There it was taken occasionally near the large
clumps of antelope-brush and manzanita which grew in the main
channels of the wash.

Lactating females of this species were taken in October, 1949,
and February, 1950. Two pregnant females were trapped on February
25, 1950, at the mouth of Palmer Canyon.

This species occurs from 1000 feet elevation to above 9000 feet
elevation on the Pacific slope of the Mountains, but although probably
the most widespread rodent in the area it is absent from many
habitats. This mouse reaches maximum abundance in the coastal
sage scrub association, particularly where the soil is sandy with
scattered vegetation—usually coastal sagebrush and black sage. On
the foothill adobe slopes none was trapped, nor have any been taken
in most of the chaparral habitats. A few gambeli were trapped amid
the talus beneath growths of scrub oak and bay trees in San Antonio
Canyon, at 4300 feet elevation. On Blue Ridge, at elevations of
from 7200 feet to 8300 feet, this mouse inhabited areas clothed with
snowbush, basin sagebrush, currant, and scattered conifers, and
was found sparingly in the coniferous forests. Thus this species
lives on contrasting soil types in association with many different
vegetational assemblages, from the coastal base to the crest of the
range.

There is a rather wide variation in color in gambeli from the
San Gabriels. Certain individuals taken in open, sandy coastal
sage areas are pale, some being indistinguishable from examples of
sonoriensis taken in the pinyon-juniper association on the desert
slope. Specimens from San Antonio Canyon have somewhat darker
pelage than those from the sage belt, and than individuals taken
on Blue Ridge. Possibly a large series of Peromyscus maniculatus
from the San Gabriel Mountains would show definite local trends
in color of pelage.

This species is active on sub-freezing and rainy nights as evidenced
by trapping results, and at Big Pines there were tracks
around the bases of conifers after a heavy snowfall in December,[Pg 557]
1951. Several females taken in the sage belt in October, 1948,
carried embryos, and a lactating female was recorded from Blue
Ridge on November 13, 1951. Juveniles have been taken in September,
October, November, and December.

This subspecies is associated with contrasting types of soil and
vegetation. It is seemingly absent from the upper pinyon-juniper
sage flats and areas grown to chaparral, but is fairly common on
the gravelly benches dotted with junipers, and in the washes issuing
from the canyons on the desert slope. It is present in small numbers
in the Joshua tree association.

In 1951 the numbers of sonoriensis were noticeably less than in
1948; probably this was correlated with the series of dry winters
in this period. In December, 1948, this animal was one of the most
common rodents in Mescal Wash, 200 trap-nights yielding thirteen
specimens; but in November, 1951, none was taken. In parts of the
juniper belt, where an average of about six sonoriensis was taken
per 100 trap-nights in 1948, the average had dropped to one per 100
trap-nights in 1951.

Specimens of this species from the desert slope of the mountains
have been assigned to the subspecies sonoriensis. Those from Blue
Ridge tend toward sonoriensis in color, and may be considered as
intergrades between this subspecies and gambeli.

This species was active on nights when the temperature was as
low as 10° F., and individuals were trapped in the juniper belt in
December, 1948, when four inches of snow lay on the ground.

Gray-pelaged juveniles were taken on the desert slope in December,
1948, and a female taken in Mescal Canyon on December 22
of this year carried four embryos near term.

The main range of this mouse in the San Gabriel Mountains lies
between 1600 and 6000 feet elevation on the Pacific slope of the
Mountains, thus encompassing much of the chaparral and oak[Pg 558]
woodland associations. It was the most common mammal in the
oak woodland association in the lower foothills and often was
trapped there on leaf mold beneath the oaks. While trapping for
shrews I regularly took this species in riparian growth right down to
the edge of the water. In San Antonio Canyon many boylii were
trapped beneath logs and dense vegetation, and on wet seepage
slopes adjacent to the creek.

This species shows a definite predilection for rocky habitats
where these occur in the chaparral. In heavy lilac brush near
Camp Baldy Peromyscus boylii was outnumbered by P. californicus,
yet where talus slopes or boulder piles occurred boylii was
more numerous. At the head of Cow Canyon amid boulders
beneath scrub oak, bay, and big cone-spruce, this species was
especially abundant and no other Peromyscus was taken.

Of special interest is the occurrence of this mouse on the desert
slope of the mountains; there it was taken beneath scrub oaks in
the pinyon-juniper association at the mouth of Mescal Canyon, and
amid boulder and debris piles in Mescal Wash at 4000 feet elevation.
While manzanita and scrub oak grew in the wash at the
points of capture, the animals were actually surrounded by the
desert conditions of the Joshua woodland, and associated with such
desert forms as Onychomys torridus pulcher and Peromyscus eremicus
eremicus.

Immature individuals were taken in October, November, February,
and March, and a female with two large embryos was taken
near Icehouse Canyon on November 8, 1951.

Only once was this mouse found outside the pinyon-juniper
association of the desert slope; in November, 1949, several were
collected near Cajon in mixed manzanita, scrub oak, and greasewood
chaparral. This was the only Peromyscus of regular occurrence
in the pinyon-juniper area, and was recorded from the upper limit
of this association, near Jackson Lake, at 6000 feet, to the lower
limit of the association at the mouth of Graham Canyon at roughly
4000 feet elevation.

Although in the juniper belt truei often occurs on common ground[Pg 559]
with Peromyscus maniculatus sonoriensis, the habitat preferences
of these animals are generally complementary. Where the mice occur
together, traps set in a variety of locations caught Peromyscus
maniculatus, but typically traps set amid the brush or on the open
ground away from the junipers were productive. On the contrary
truei was invariably trapped quite near the junipers and often in
association with the large nests of Neotoma fuscipes simplex. In
fact traps set right on the beds of litter beneath the junipers were
most likely to catch truei. Records kept of trapping localities show
that truei was without exception trapped within twenty feet of
some treelike shelter such as junipers, pinyons, Joshua tree or scrub
oaks. Thus Peromyscus maniculatus occupies the open stretches
between the trees, while truei inhabits the ground beneath and
immediately adjacent to the trees. In Nevada the piñon mouse
prefers rocky areas (Hall, 1946:520). In the San Gabriel Mountains
this mouse does not seem to have this predilection.

In the juniper belt truei was second to Dipodomys panamintinus
in point of numbers. In the course of 500 trap-nights in the juniper
belt twenty-two truei were taken with thirty-six Dipodomys.

I consider my series of Peromyscus truei from the desert slope
of the San Gabriels to represent the subspecies montipinoris.
The series is closely comparable to specimens of the subspecies
montipinoris in the California Museum of Vertebrate Zoology from
the Mount Pinos area, but differs from specimens of the race
chlorus from the San Bernardino Mountains in certain diagnostic
characteristics. In his recent paper on Peromyscus truei, Hoffmeister
(1951) considered the populations of this species in the
San Gabriels to be of the race chlorus. Hoffmeister had only one
specimen available from the San Gabriel Mountains (Lytle Creek,
on the Pacific slope) which was intermediate between montipinoris
and chlorus, but on the basis of cranial measurements it was referred
to the race chlorus. Specimens of Peromyscus truei from the
eastern end of the desert slope of the San Gabriel Mountains
and the Cajon Pass area would probably demonstrate that the race
montipinoris, which occupies the desert slope of the San Gabriels,
intergrades with the race chlorus, which occurs in the San Bernardino
Range immediately to the east, in the Cajon Pass area. Although
montipinoris occurs on the desert slope of the San Gabriels,
chlorus may occur on the Pacific slope. I took no specimens of the
piñon mouse on the Pacific slope of the San Gabriel Mountains.

In December, 1948, many small juveniles were taken in the[Pg 560]
juniper belt, and on October 15, 1951, two females trapped at the
head of Grandview Canyon had embryos: one three and the other
four. On November 13, 1951, a partially gray-pelaged subadult
female was trapped which had recently suckled young.

Grasshopper mice seemed to be partial to the more sandy parts
of the Joshua tree flats where the mice were trapped regularly but
not abundantly. This mouse inhabited the barren sandy channels
of Mescal Wash but was rare on the adjacent juniper-clad benches.
In the arid, sandy washes this typical desert rodent penetrated the
high pinyon-juniper association.

Wherever grasshopper mice occurred they were outnumbered by
most of the other rodent species. For example, on November 26,
1949, below Graham Canyon, 100 snap traps yielded 10 Dipodomys
panamintinus mohavensis, 2 Dipodomys merriami merriami, 4 Peromyscus
maniculatus sonoriensis, and 3 Onychomys torridus pulcher.

Where abandoned kangaroo rat burrows were common in the
Joshua tree belt these burrows were used as retreats by Onychomys.
Some traps set at the entrances to old burrows caught grasshopper
mice.

This species was on the Pacific face of the Mountains from 1600
feet elevation in the coastal sage belt, to 4800 feet elevation in open
groves of big cone-spruce and scrub oak of the chaparral association.

The local distribution of this woodrat is determined by suitable
nesting sites. Although taken in different types of vegetation,
lepida, without exception, was associated with rocky areas or areas
supporting patches of prickly-pear cactus. In the channels of San
Antonio Wash, lepida was commonly associated with jumbles of
boulders and boulder-dotted cut banks. There the vegetation is
sparse, and the rats dwell among the rocks; only their droppings and[Pg 561]
faint trails indicate their presence. Among boulders lepida builds
only small houses of sticks and debris, and even these only occasionally.
The effect of the prickly-pear cactus on the distribution
of lepida in the sageland is striking; trap lines there yielded no
woodrats where extensive rock piles and patches of prickly-pear
were absent, but many rats were taken where patches of prickly-pear
are plentiful. On an acre supporting coastal sagebrush at the
mouth of San Antonio Canyon, at 1800 feet elevation, there were
fourteen patches of prickly-pear, each covering at least thirty square
feet. In these patches there were thirteen occupied woodrat nests.
Only one patch lacked an occupied nest, and this one contained the
remains of an old nest. On this acre there were at least thirteen
individuals. In the sagebrush belt only an occasional large patch
of cactus lacks a woodrat house occupied by lepida. Seemingly
Neotoma fuscipes does not build houses in patches of prickly-pear.

Most of the houses built by Neotoma lepida are small and simple
as compared to those of Neotoma fuscipes, and often in rocky
areas no nests are in evidence. The most elaborate nests are built
among the pads and spines of the prickly-pear and under laurel
sumac or other large shrubs growing near washes. One of three
houses examined at the mouth of San Antonio Canyon was on
sandy ground in a patch of Opuntia measuring approximately 11 x 14
feet. The house was 14 inches high and 41 x 37 inches at the base.
It was built around the main stem of the prickly-pear and a rock
about 10 inches in diameter. The house was constructed of sticks
of coastal sagebrush and buckwheat, and was dotted with dissected
fruits and flowers of the prickly-pear. The main chamber
was arched over by the main stem of the prickly-pear and was
roughly 12 x 19 inches, inside dimensions, being reached through
two three-inch openings, one on the east side of the chamber and
one on the north side of the chamber. Two cup-shaped nests were
inside the chamber, these being constructed mostly of grasses, and
each resembling a well constructed bird nest 4 inches in diameter.
The grass nests were free of feces, but feces were piled up against
the west side of the chamber with many snail shells and dissected
fruits and flowers of prickly-pear. Thirty-five inches from the main
chamber was a third grass nest on the ground beneath a cluster of
cactus pads. Next to this there was a blind burrow about eight
inches long, and one and three-quarters inches in diameter. No
burrow led to the main chamber, in this or in either of the other[Pg 562]
houses, but all had at least one short blind burrow beneath the
house.

At many houses there were one to three grass nests outside the
house on the ground, within four feet of the house. From each nest
a well worn path lead to the house. Traps set in these nests invariably
caught woodrats.

The many prickly-pear fruits and snail shells in and around the
houses of lepida probably were remnants of food. So many of
the rodents caught in traps near woodrat nests were partly eaten—usually
the brains were taken—that I suspect the woodrats of
eating their relatives. The heads of many composite annuals were
piled near woodrat nests.

Immature individuals were taken in September, October, and
early November, and on September 26, 1951, a lactating female was
trapped near Palmer Canyon.

An old female bobcat trapped in Thompson Canyon had masses
of cactus thorns beneath her skin, especially about the forelegs.
These thorns were probably received while she was foraging in
growths of prickly-pear for woodrats. The other bobcats from
San Antonio Wash also had accumulations of thorns under the skin
of the forelegs. Fragments of the skulls of Neotoma lepida were
recovered from horned owl pellets and coyote feces.

These woodrats were present in rocky situations along the desert
slope from the lower edge of the juniper belt down into the desert.
Specimens were taken in piles of boulders in Mescal Wash, and
amid rock outcroppings on the steep, barren, south slopes at the
base of Grandview Canyon, whereas none was found on the juniper-clad
benches.

This woodrat built no nests in rocky areas; however, in the Joshua
tree belt N. l. lepida often built small nests at the bases of large
standing or prostrate Joshua trees. There sticks from creosote
bushes, along with cow dung and small stones were favorite building
materials. Judging from the large number of unused woodrat
nests in the Joshua tree flats it seemed that this rat was formerly
far more common than it was in the period of this study.

This subspecies was widely distributed along the coastal slope of
the mountains from the coastal sage belt, at roughly 1600 feet, up to
6500 feet at the lower edge of the yellow pine forest and was most
common in the chaparral association.

In the coastal sage belt these woodrats are restricted to wash
areas where large chaparral plants such as lemonadeberry and
laurel sumac are used as nesting sites. In San Antonio Wash the
occasional large juniper trees almost invariably harbor the nests
of fuscipes. The general absence of suitable nesting sites in the
sage belt probably limits the spread of fuscipes in this area.

In the upper part of the chaparral belt in talus these woodrats
live beneath the angular boulders and build no visible houses. Several
areas of talus occupied by woodrats were examined carefully
and no sign of houses was noted.

Two juveniles were found in the stomach of a rattlesnake (Crotalus
viridis helleri) killed in May, 1948, at the mouth of Evey Canyon.
Remains of woodrats were found in feces of the coyote and gray
fox.

Lactating females of this species were taken on March 16, and
October 2, 1951.

These rats were recorded from the yellow pine forests on Blue
Ridge, at 8100 feet, down to the lower edge of the juniper belt, at
3800 feet. Their presence there as elsewhere was determined by
the occurrence of adequate cover. On Blue Ridge they were taken
in and near patches of snowbrush, currant, and choke cherry, and
one was taken beneath a pile of logs where no nest was in evidence.

The thickets of choke cherry in hollows on Blue Ridge were
favored house-building sites of woodrats. Among the tangle of
branches large nests were built, and in September, 1951, the remains
of choke cherry fruit and gnawings on the limbs of these
plants indicated that woodrats were active throughout these extensive
patches of brush.

In the pinyon-juniper association most of the large plants were[Pg 564]
used as nesting sites, but scrub oak, seemed to be especially preferred.
Because it often grew in a twisted irregular form with the
foliage nearly reaching the ground, the oak offered good shelter for
the woodrat nests. In an acre of scrub oak and mountain mahogany
brush one-half mile north of Jackson Lake, at 6100 feet, thirteen
occupied woodrat nests were found. In the juniper belt, houses
were of more irregular occurrence, and were always beneath juniper
trees, usually beneath the largest and most widely spreading
individuals.

Those specimens from Blue Ridge, on the crest of the San
Gabriels, are intergrades between the coastal race macrotis and
simplex of the desert slope. Although specimens vary widely in
color, comparison with series of these two subspecies in the California
Museum of Vertebrate Zoology indicates that all specimens
from the desert slope of the San Gabriels are referable to the race
simplex. Two specimens of this species from the granite talus above
the base of Icehouse Canyon at 5500 feet on the Pacific slope,
grade strongly toward simplex. Hooper (1938:231) mentions that
specimens of this species taken along the San Gabriel and San
Bernardino ranges may be intermediate between simplex and
macrotis.

At the head of Grandview Canyon, tracks indicated that a coyote
had foraged for about one half mile along the edge of a tract of
dense oak and pinyon growth. It seemed as if the animal had been
foraging for woodrats. A gray fox trapped near Graham Canyon,
in the juniper belt, had in its stomach the remains of a freshly killed
adult woodrat. The remains of an adult woodrat were found in the
stomach of a rattlesnake (Crotalus viridis helleri) obtained on the
desert slope of the mountains.

Owing to the paucity of extensive areas of grassland in the San
Gabriels, this is one of the least common rodents of the area. It
inhabits, however, even small patches of grassland up to 4000 feet
elevation on the Pacific slope, and is locally plentiful. For example,
a small patch of grassland amid the chaparral at the mouth of[Pg 565]
Palmer Canyon supported many Microtus, and in San Antonio
Canyon at about 3000 feet elevation meadow mice were found amid
boulders and yuccas in a small grassy area near the stream.

Eleven black bears were introduced into the San Gabriel Mountains
"near Crystal Lake" in November 1933 from the Sierra Nevada
(Burghduff, 1935:83). I do not know whether or not there have
been subsequent introductions. There are still bears present in the
higher parts of the mountains, especially north of the study area,
where they seem to be maintaining their numbers. The grizzly
bear that formerly occurred in the San Gabriel Mountains was
exterminated there some years before the black bear was introduced.

Large sections of the San Gabriel Mountains are uninhabited by
this species, while locally, in the chaparral belt near water, ring-tails
are common. Many reports of ring-tails were received from
owners of cabins and homes who reside in the canyons at the Pacific
base of the mountains. Because of the distinctive appearance of this
animal it is likely that many of these reports were accurate. The
reports testified to the presence of ring-tails in San Gabriel Canyon,
Dalton Canyon, Palmer Canyon and San Antonio Canyon. Hall
(1927:41) lists specimens from San Antonio Canyon. Kenneth Hill
of Upland told me that ring-tailed cats often have been trapped
above that town near citrus nurseries that are regularly irrigated.
This species probably is not present on the desert slope of the
range.

The only specimen that I took was a female weighing one pound
and fourteen ounces. It was trapped on March 24, 1951, among
granite boulders, beneath scrub oak and bay trees, near the mouth
of Icehouse Canyon, at 5500 feet elevation.

The raccoon was one of the most common carnivores in the San
Gabriels and was found on both slopes of the range. Tracks were
noted and one old male was trapped at the base of the Pacific slope
foothills at 1900 feet elevation, and raccoons were captured at
several localities from this point up to 5500 feet in San Antonio
Canyon. They were noted on Blue Ridge at about 8000 feet elevation
foraging around the camp grounds. On the desert slope they
occurred down to the lower edge of the pinyon-juniper belt, for
example near the mouth of Sheep Creek Canyon.

Sign of raccoons was most often found near water; tracks, however,
indicated that these animals, along with other carnivores, used
fire roads for traveling through the chaparral. In a small draw
one-half mile east of the mouth of Thompson Canyon two raccoons
were trapped although the only water was a series of small, disconnected
seepage pools beneath the valley oaks.

A raccoon freed from a small steel trap in San Antonio Canyon
concealed itself in an unusual but extremely effective manner. When
released the coon splashed up the middle of the small creek nearby
to a place where some dead alders had fallen over and shaded the
water—here the animal squatted down in the stream. The raccoon
was mostly submerged, its tail was floating, and its back and
the top of its head and snout were above water. With most of its
body under water, and with the maze of alder logs above casting
a broken pattern of light and shade, it was well hidden. When
closely pressed the raccoon hid in the same manner several times
before it disappeared up a rocky draw into the scrub oak brush.

In the autumn of 1951, raccoons fed on grapes at the Sycamore
Valley Ranch one mile south of Devore. The one specimen (P. C.)
saved, an old male from 1/2 mi. W Palmer Canyon, had remains of
beetles in its stomach and weighed slightly more than 13 pounds.

Several weasels were found dead on roads in the coastal sage
belt near San Antonio and Lytle canyons.

I found no sign of badgers on the Pacific slope of the range, but
James Wolfort, employed by the state Fish and Game Commission
to trap coyotes, reported that in 1948 he trapped also several badgers
at the coastal foot of the range in the San Fernando Valley area
which is west of the study area.

Many old badger diggings were found in the Joshua tree woodland
and pinyon-juniper associations of the desert slope, but none
of the animals was observed nor were specimens secured. Mr.
E. A. Eberle who has trapped for many winters in the vicinity of
Mescal Canyon stated that he caught badgers occasionally.

I examined the skin of a badger taken at Llano which showed
the characteristic paleness of the desert subspecies berlandieri.

The populations of striped skunks in the San Gabriels center
around cultivated land at the Pacific foot of the range. Citrus groves,
grape vineyards, and areas once cleared by man are preferred to
coastal sagebrush flats. The cultivated areas now probably support
many more skunks than were there under original conditions.
I have many sight records of striped skunks which I obtained while
driving through the citrus groves at night. Only once was the
striped skunk noted in the chaparral; all the other records were
from the coastal sagebrush belt.

In addition to insects and small mammals, grapes are eaten regularly
by skunks in vineyards, and the fruit of the prickly-pear cactus
is often eaten. Near the mouth of Thompson Canyon feces examined
in October 1948, contained almost exclusively the remains of prickly-pear
fruit.

A male taken one-half mile south of Devore weighed five pounds
and four ounces.

Spotted skunks are common locally in the coastal sage scrub
association and lower chaparral association on the coastal face of
the mountains, mainly between 1000 and 4000 feet elevation; but
they have been reported from Icehouse Canyon at 5000 feet, and
I took one above the mouth of this canyon at 5500 feet elevation.
A few spotted skunks may inhabit the lower desert slope of the
mountains; here feces thought to be those of spotted skunks have
been found, and a bobcat trapped near the head of Grandview Canyon
smelled strongly of skunk.

The spotted skunk usually was in rocky habitats. In the sage
flats, sign (mostly feces and tracks) usually was near rock piles and
around human developments such as rock walls, old outbuildings
and houses. Specimens taken in the chaparral were trapped near
granite outcroppings.

In the autumn of 1950, at my house near the mouth of Palmer
Canyon, a family of spotted skunks lived under the floors. Night
after night they scratched under the floor and chattered in high-pitched
rasping notes, and on several evenings one walked complacently
into the living room. It finally became necessary to trap
and deport most of these skunks. In all, nine skunks were trapped;
these probably represented more than the original residents. One
male was descented and allowed to remain. It spent most of the
daylight hours asleep in an old shower room where the many gaps
between the rock work and the boards allowed him entrance.
Through no special efforts on our part he became tame enough
to climb over us in order to get food left on the kitchen sink, and
he would eat calmly while we sat only inches away from him.

Feces from sage areas contained mostly remains of insects and
small rodents whereas many samples of feces from chaparral areas
contained, in addition, shells of snails. Feces examined represent
all months of the year.

Coyotes inhabit the sagebrush flats and foothills up to at least
4000 feet all along the Pacific base of the San Gabriels. This
species seems most common at the foot of the range where large[Pg 569]
dry washes prevent man from occupying the land immediately adjacent
to the foothills, and are the dominant carnivores of the
coastal sage belt. Repeated observations have indicated that although
many individuals range into the higher foothills they
seldom are found deep in the major canyons or chaparral slopes.
Coyotes rarely occur at 3000 or 4000 feet in San Antonio Canyon
where it cuts into the realm of heavy chaparral; yet on steep foothill
slopes and ridges, which are adjacent to the flat land, these
animals range up to at least 4000 feet. Being hunters primarily
of rather open land many coyotes go into the foothills only to find
daytime refuge, traveling down dirt roads, ridges, and firebreaks, to
forage at night in the sage flats. Coyote feces from the foothills, at
about 3500 feet, contained predominantly the remains of such food
items as cottontails, chickens, and jack rabbits. These animals
could have been found only in the flats. This is additional evidence
that coyotes do the major part of their hunting at the base of the
range.

Observations of coyote tracks and trapping records have shown
that these animals hunt mostly in the more open parts of the
sage flats. Coyotes frequent areas of scattered brush, sandy areas,
wash channels, and old roads, and seemingly shun dense brush.
Many coyotes actually hunt for rabbits in the citrus groves near the
foothills. On several evenings I traced their howling to orange
groves, and Mr. Kenneth Hill of Upland told me of often seeing
coyotes in his orange groves at night.

The forage beats of several coyotes were discovered in connection
with trapping specimens of these animals. In January, 1952, two
coyotes, probably a mated pair, traveled nightly from the slopes
immediately west of Evey Canyon, at about 3100 feet, down into
the sagebrush adjacent to the west side of San Antonio Wash,
at about 1700 feet elevation. The route led down open ridges,
then for about one half mile across a level, cultivated plateau,
and then swung over the eroded banks near the lowermost point
of the plateau onto the level sage flats. The distance covered by
this route from the foothills down to the flats was somewhat more
than a mile, with about a 1400 foot difference in elevation between
the daytime retreat and the nocturnal forage area. Another route,
seemingly used by only one coyote, was somewhat longer. This
animal followed fire breaks and ridges from above Thompson Canyon
down onto a fire road, and then into the lower end of Palmer
Canyon where it entered the flats. This route covered about three
miles in coming from the foothills to the flats. Feces of this coyote[Pg 570]
often contained the remains of white leghorn chickens which had
been found at a refuse pile near several chicken ranches one-half
mile from the base of Palmer Canyon.

Although no definite idea could be gained of the population
density of coyotes in the area, it was clear that in certain localities
they were, as carnivores go, abundant. After one large male was
obtained in the flats at the base of Cobal Canyon, at least two other
individuals were heard howling in this immediate area, and their
tracks were noted repeatedly on dirt roads. One night early in
January, 1952, immediately west of the head of San Antonio Wash,
the voices of six coyotes could be picked out separately from a
chorus of coyote howls which came from several different directions
in the wash.

Many field examinations of coyote feces left the impression that
chickens and lagomorphs made up the bulk of the coyote's food on
the coastal slope. To check this a study of 39 sets of scats collected
at various localities on the coastal slope was made in the laboratory,
the results being shown in Table 10. Remains of one of the three
species of rabbits, cottontails, jack rabbits, or brush rabbits, occurred
in 72 per cent of the feces examined. Cottontails, it will
be noted, were preyed upon more heavily than any other wild
species, remains of this form being found in 33 per cent of the feces.
The prevalence of chicken remains in coyote feces does not imply
that these animals were killed by the coyotes. All of the chickens
could have been found dead in the refuse piles of the many
chicken ranches. In addition, the chickens were raised in wire
cages above the ground where they were nearly invulnerable to
predation. That coyotes may at times kill deer in this area was
suggested by the finding of tracks in the sand in San Antonio Wash
which clearly indicated that a deer had been closely pursued by a
coyote. The tracks were lost in a stretch of brush so the outcome
of the chase could not be determined. Near the mouth of Lytle
Creek Canyon, in November, 1951, coyote feces contained mostly
remains of grapes from nearby vineyards. Also, above Cucamonga,
coyotes were found to be feeding heavily on grapes. This must be
a rather unsuitable form of nourishment for coyotes, for many of the
grapes in the feces appeared nearly unaltered despite their trip
through the alimentary canal.

Table 10.—Results of Examinations of Thirty-nine Sets of Coyote Feces
from the Pacific Slope of the San Gabriel Mountains. Feces Were
Deposited in Autumn and Winter (September to February).

The six coyotes taken on the Pacific slope are fairly uniform in
coloration; the occurrence of white tipping on the tails of most of the
specimens, instead of the usual solid black tip, is notable. Three[Pg 571]
skins, those of a male and two females, have patches of white hairs
at the tips of the tails; two skins, of a male and a female, show only
scattered white hairs at the tips of the tails; and the skin of one
female has a solidly black-tipped tail. An additional female,
[Pg 572]
trapped by David Leighton in Thompson Canyon, had a large patch
of white hairs at the tip of the tail. Grinnell, Dixon, and Linsdale
(1937:501) mention that only an occasional individual (female?)
has a white-tipped tail.

Weights are available for four specimens: two coyotes trapped
in San Antonio Wash, a male and a female, weighed 20.5 and 23.2
pounds respectively; a female from the mouth of San Antonio
Canyon weighed 21.6 pounds; and a large male from the mouth of
Thompson Canyon weighed 29.3 pounds.

Table 11.—Cranial Measurements of Canis latrans ochropus from the
Coastal Slope of the San Gabriel Mountains.

Coyotes are common on the desert slope of the San Gabriels
below about 6000 feet elevation. They seem not, or only rarely, to
penetrate the yellow pine forest belt, but tracks have been found
occasionally near the lower edge of the forest, as at the head of
Mescal Canyon. In the more open parts of the pinyon-juniper
association, sign of coyotes was noted and they were the dominant
carnivores in the juniper belt and Joshua tree woodland.

In the upper part of the pinyon-juniper association coyotes travel
and forage in sage flats, along ridges, and in sandy draws, avoiding
the extensive patches of scrub oak and mountain mahogany, and[Pg 573]
the steep, rocky, pinyon-covered slopes. It is apparent that the
local ranges of the coyote and the gray fox in the pinyon-juniper
belt are complementary, the gray fox keeping to the more thickly
wooded or brushy parts of the area, and the coyote staying in the
relatively open sections. Probably there is little competition for
food there between these two canids.

As evidenced by tracks, coyotes commonly traveled and hunted
along desert washes, probably because of the larger population of
rodents and rabbits there. Below Graham Canyon three fairly recently
inhabited dens of coyotes were found in the cutbanks at the
edge of a dry wash in December of 1951. The cutbanks were six
to ten feet high, and the dens were dug into the banks about three
feet above the floor of the wash.

On the evening of October 20, 1948, near Desert Springs, Steven
M. Jacobs and I set out a line of fifty wooden live traps for kangaroo
rats. That night we slept about 300 yards from the middle of the
line which was roughly three quarters of a mile long. When we
tended the traps the next morning we found the tracks of a coyote
over our own tracks of the previous day, and the first trap that had
seemingly held a kangaroo rat was chewed and dragged for about
fifty feet. Each trap that had held a rodent had been turned upside
down so that the door had opened. At one point in the line
where we had walked for about two hundred yards without setting
a trap the coyote had followed every twist and turn of our
trail. The animal had followed out the entire trap line and removed
approximately eight rodents from the traps, reducing our take to
one Dipodomys and one Peromyscus.

Examinations of feces showed that in the period from 1948 to
1952, while populations of jack rabbits were low in the Mojave
Desert, the coyotes had fed extensively on smaller mammals such
as kangaroo rats, and to some extent on fruit. By contrasting the
present food habits of coyotes on the desert and coastal slopes of
the mountains support is afforded for Errington's (1937:243) statement
that predation is "a by-product of population." On the desert
slope, with low populations of rabbits, the coyotes have turned to
lesser species of prey; while on the Pacific slope, where populations
of rabbits were high, the rabbits made up the major portion of the
coyote's diet. On the desert slope, remains of the following food
items were identified from coyote feces: kangaroo rats, mule deer,
jack rabbits, passerine bird, manzanita and juniper fruit, beetles,
grapes and apples. Near Valyermo, coyote feces were composed[Pg 574]
mostly of apples from nearby orchards. A female coyote killed
below Grandview Canyon had its stomach and intestines stuffed
with apples in large chunks. In the juniper belt, berries of juniper
were often eaten by coyotes.

The three specimens of coyotes from the desert slope are clearly
referable to the desert race C. l. mearnsi, both with regard to cranial
and pelage characteristics. Although I collected no specimens
from Cajon Pass or the passes at the west end of the range, it is in
these places that intergradation might be expected to occur between
the desert race C. l. mearnsi and the coastal and valley subspecies
C. l. ochropus, as the higher parts of the San Gabriels seem to constitute
a barrier to coyotes.

A subadult female coyote taken in the Joshua tree belt near
Graham Canyon weighed 20.8 pounds.

The kit fox barely enters the area under consideration. In the
Joshua tree belt, below about 3500 feet elevation, tracks were most
often noted in washes and on the adjacent sandy ground. The
highest place where tracks were seen was a small sandy draw
below the mouth of Graham Canyon at an altitude of roughly 3900
feet.

In the Joshua tree belt many old burrows were found but none
was occupied. I believe these foxes are returning to this area
where once they were common. In the winter of 1948 no sign of
kit foxes was found, although intensive field work was done in the
Joshua tree belt in the Mescal Canyon area. In December of 1951,
in the same locality, sign was obvious and an individual was trapped
below Grandview Canyon at 3500 feet elevation. Possibly since
the use of poison for carnivores has been discontinued in this district
the foxes are repopulating the area.

The one specimen taken, a sub-adult female, weighed two pounds
and fourteen ounces.

The gray fox is widely distributed in the San Gabriel Mountains,
occurring on both slopes of the range wherever extensive tracts
of chaparral are present. They reach maximum abundance in the[Pg 575]
chaparral association of the coastal slope. Individuals have been
observed occasionally at night in coastal sage areas at the Pacific
foot of the mountains; however they seem to be less common here
and probably come out of the adjacent chaparral to forage in the
flats at night. Gray foxes occur all the way up the Pacific slope
into the yellow pine woodland at 7500 feet, and from 6200 feet elevation
on the desert slope down to the upper limit of the Joshua trees
as, for example, near Mescal Canyon at 4700 feet.

On the Pacific face of the mountains the gray fox probably is the
dominant carnivore in terms of its effect on prey species, first, because
of its abundance, and second, because of its forage habits.
Some appreciation of the abundance of the gray fox may be gained
from trapping records. On a fire road at the head of Thompson
Canyon, at 2500 feet, two settings of traps about one-quarter mile
apart were maintained for four nights. In this time four gray foxes
were trapped. At the head of Cow Canyon, at 4500 feet, one trap
set on a deer trail caught five gray foxes in five nights. At the end
of this time fox tracks were noted about 100 yards away from the
set, and another fox was trapped about one quarter mile away. In
addition to their abundance, the forage habits of gray foxes are such
as to bring them into most habitats present in the chaparral association.
Tracks and feces indicate that foxes forage under dense brush,
on open rocky ridges, in riparian growth, on talus slopes, and in
groves of big cone-spruce and scrub oak.

Trapped foxes, if uninjured by the trap, were usually released.
One fox was released on a small trail through thick vegetation consisting
mainly of snowbrush. When freed, the fox whirled and
darted through a patch of snowbrush for about seventy-five feet,
then turned and disappeared beneath some large bay trees. Although
the brush through which it ran was dense, the fox seemed
to run at full speed. The success of gray foxes as predators in the
chaparral is probably due in large measure to their agility amid
dense cover.

The three specimens from the desert slope are referable to the
coastal subspecies, U. c. californicus, rather than the desert subspecies,
U. c. scottii. In all respects they resemble foxes taken on
the Pacific slope; cranial measurements are near the maximum for
the large U. c. californicus, and not small as would be expected if
they were grading toward the smaller U. c. scottii. Floors of desert
valleys north of the San Gabriel Mountains probably isolated foxes
there from U. c. scottii found in the higher ranges of the Mojave[Pg 576]
Desert. Consequently one would expect no intergradation between
the coastal and desert races in the San Gabriel Mountains.

An old female trapped on March 18,1951, in San Antonio Canyon,
had three embryos each about 105 mm. long from rump to crown,
and weighed 9.2 lbs. The average weight of four non-pregnant females
was 6.8 lbs., whereas the average of six males was 7.5 lbs.

Wildcats range over the whole of the San Gabriel Range, with
the possible exception of the tops of the highest peaks such as Mt.
San Antonio and Mt. Baden Powell. Sign of these animals has been
observed, or specimens have been taken, from the coastal sage belt
up to about 8500 feet in the yellow pine forests on Blue Ridge.
The subspecies baileyi occurs on the desert slope of the range.

Wildcats are most common in the chaparral belt where they forage
widely from the ridges down into the canyons. Judging from trapping
records bobcats are not so common here as the gray fox.

Bobcats occur in the sage belt, where they are most common in
the broken country around washes and in brushy areas. Although
bobcats and coyotes occupy the same general areas here, the habitat
preferences of these animals seem to be different, with coyotes
occupying the more open country. An indication of the hunting
habits of bobcats is furnished by the occurrence of masses of prickly-pear
thorns beneath the skin of the legs, particularly the forelegs, of
three specimens trapped in the sage belt. These thorns probably
were acquired while the bobcats foraged for woodrats or cottontails
in the patches of prickly-pear, which are locally abundant in the
sage belt.

On March 12, 1951, a small subadult female bobcat, trapped at
4000 feet in San Antonio Canyon, was found dead in the trap and
had numerous deep cuts around its head and shoulders, and severe
bruises on the right shoulder. The spacing of the cuts, and the
tracks around the set, indicated that while held in the trap this
animal had fought with a second bobcat that had inflicted the fatal
wounds. It seems unlikely that the fight was caused by a male[Pg 577]
attempting to copulate with the female held in the trap, for the
female was found to be carrying an embryo.

In Live Oak Canyon, in December, 1950, tracks and bits of fur
indicated that a bobcat had killed and eaten a gray squirrel. Remains
of cottontails were found in the stomachs of two bobcats.
All six bobcats from the Pacific slope had nematode worms in the
pyloric end of the stomach.

Two females obtained on March 12 and 19, 1951, each had one
embryo approximately one inch long (rump to crown).

The following list gives the weight of each of the specimens from
the Pacific slope of the San Gabriels.

Table 12.—Weights of Lynx rufus californicus from the San Gabriel
Mountains.

This subspecies is widely distributed on the desert slope of the
range, and was recorded down to the lower edge of the juniper
belt. Tracks were observed on many occasions in yellow pine forest,
but wildcats seemed to be commonest in the brushy parts of the
pinyon-juniper association. Two were trapped in small draws lined[Pg 578]
with pinyons and scrub oak, and two at the base of rocky pinyon-covered
slopes. Only occasionally were tracks noted in the lower
part of the juniper belt. Bobcats are most numerous where woodrats
also reach peak abundance, suggesting that woodrats are a
major food.

The four specimens from the desert slope, although exhibiting a
wide range of variation, are all representatives of the desert race
baileyi. A yearling male from near the head of Grandview Canyon,
at 5200 feet elevation, has the profuse black spotting of the subspecies
californicus, but the general pallor dorsally is characteristic
of the desert subspecies. An adult female, from 4700 feet elevation
in Graham Canyon, shows the double mid-dorsal black line and the
distinct black markings around the face characteristic of californicus,
but is otherwise pale with reduced black patterns on the backs of the
ears. The other two specimens, an adult male and a yearling female,
are typical examples of baileyi, pale, and with reduced black markings.
None of the specimens of bobcats from the coastal slope of
the mountains showed characters approaching those of baileyi. It
seems, therefore, that these two subspecies intergrade on the interior
slope of the range.

A yearling male weighed 12 pounds, and a yearling female
weighed 10.5 pounds. An old male weighed 19.6 pounds, and an
adult female weighed 15.1 pounds.

Remains of deer were in two of the bobcat stomachs, and one of
these stomachs also contained jack rabbit remains. Approximately
a dozen nematodes (stomach worms) were in the stomach of one
of the larger male specimens.

Several cabin owners near the mouth of Icehouse Canyon reported
seeing a lion in that area in 1950, and others said they saw huge
cat tracks in Icehouse Canyon. State Trapper James Wolfort reported
that he trapped two lions on the coastal face of the range
in 1947. Authentic reports indicate that mountain lions occur in
remote sections on both slopes of the range, and in these areas
mountain lions probably are as common as they ever were.

Mule deer are common in chaparral areas on both slopes of
the San Gabriel Mountains. The animals or their tracks have been
observed from the coastal sagebrush flats up to about 9200 feet
on Mount San Antonio, and on the desert slope down to the lower
limit of the juniper belt.

Deer are plentiful in the upper chaparral belt, and large bands
are often noted there in spring. These bands may form in the
up-mountain migration and reoccupation of areas which were
covered by winter snows. A band of fourteen was observed on
March 17, 1951, one mile east of the mouth of Cattle Canyon, and
bands of about half a dozen individuals each were often noted in
March, 1951, at the base of Icehouse Canyon. Cronemiller and
Bartholomew (1950) gave a good account of the mule deer in the
chaparral belt of the San Gabriel Mountains.

On Blue Ridge in the fall of 1951, deer were plentiful, usually
being observed near patches of snowbrush and sage. They were
seldom found in the coniferous forests. On November 6, 1951,
while tending a line of snap traps before sunup, I startled a deer
from its bed at one edge of a several-acre patch of snowbrush. In
synchrony with the noise made by this deer's rising five other deer
in various parts of the brush patch leaped up and made off. When
bedded down in these extensive brush tracts deer are probably safe
from an undetected approach, for a noiseless approach through the
brush is impossible.

Two deer skulls from the San Gabriels were examined: that of
an adult male from Evey Canyon, and that of an adult female from
the mouth of Palmer Canyon. Using as a basis for comparison the
cranial measurements for the subspecies californicus and fuliginatus
given by Cowan (1933:326), these skulls were subspecies californicus.
In none of the cranial characteristics considered did they
tend toward the southern race fuliginatus. A young adult male,
however, which was killed by a car near Cajon Pass on October 2,
1951, showed pelage characteristics of fuliginatus. Its fresh winter
pelage was dark, and had the distinct black mid-dorsal line and the
broad dorsal line on the tail mentioned by Cowan (ibid.) as dis[Pg 580]tinguishing
marks of the race fuliginatus. Its cranial measurements
were not taken. Judging from this limited material the deer in the
central part of the range, that is to say, in the San Antonio Canyon
region, are of the race californicus, while fuliginatus may penetrate
the extreme eastern end of the range.

Deer hair and bones were often found in coyote feces from the
sagebrush belt. Some of these records may represent deer eaten as
carrion. On February 6, 1952, tracks across a sandy channel in San
Antonio Wash demonstrated that a deer had been closely pursued
by a coyote. The deer had leaped from a cutbank onto the sand,
had whirled around in several sharp turns, and had run into the
adjacent brush. The tracks of a running coyote followed every
twist of the deer's trail. The trail was followed into the brush where
it was lost. Two bobcats trapped near Graham Canyon on the
desert slope had hair and bones of deer in their stomachs.

Bands of bighorn sheep occur on some of the higher and more
rugged peaks of the San Gabriel Mountains. Although I never
sighted the animals themselves, I have seen abundant signs of their
presence on the ridge sloping west from Telegraph Peak at about
9000 feet elevation. Several bands reportedly range in the head of
San Antonio Canyon, and to the south on Telegraph, Ontario, and
Cucamonga peaks. The sheep usually stay in the higher sections
of the range, generally above about 7000 feet elevation. According
to district Ranger A. Lewis some bighorns summer in the lower
East Fork of San Gabriel Canyon. The subspecific status of the
bighorns in the San Gabriel Mountains has not been definitely
determined. Following Grinnell (1933:211) they are here referred
to nelsoni. If the band can be preserved without introduction of
"alien" stock, the United States Forest Service and the California
Fish and Game Commission will have registered an achievement
that will be applauded by all persons who are interested in American
wildlife.

[Pg 581]

LITERATURE CITED

Benson, S. B.

Borell, A. E.

Burghduff, A. E.

Burt, W. H.

Cowan, I. Mc.

Cronemiller, F. P., and Bartholomew, P. S.

Errington, P. L.

Grinnell, H. W.

Grinnell, J.

Grinnell, J., Dixon, J., and Linsdale, J. M.

Grinnell, J., and Swarth, H. S.

[Pg 582]

Hall, E. R.

Hooper, E. T.

Jackson, H. H. T.

Merriam, C. H.

Munz, P. A., and Keck, D. D.

Oakeshott, G. B.

Pequegnat, W. E.

Sanborn, C. C.

Vaughan, T. A.

von Bloeker, J. C.

Willett, G.

Transmitted July 20, 1954.

◻

25-5184

UNIVERSITY OF KANSAS PUBLICATIONS,

MUSEUM OF NATURAL HISTORY

Institutional libraries interested in publications exchange may obtain this
series by addressing the Exchange Librarian, University of Kansas Library,
Lawrence, Kansas. Copies for individuals, persons working in a particular
field of study, may be obtained by addressing instead the Museum of Natural
History, University of Kansas, Lawrence, Kansas. There is no provision for
sale or this series by the University Library which meets institutional requests,
or by the Museum of Natural History which meets the requests of individuals.
However, when individuals request copies from the Museum, 25 cents should
be included, for each separate number that is 100 pages or more in length, for
the purpose of defraying the costs of wrapping and mailing.

* An asterisk designates those numbers of which the Museum's supply (not the Library's
supply) is exhausted. Numbers published to date, in this series, are as follows:

• Vol. 1. 1. The pocket gophers (Genus Thomomys) of Utah. By Stephen
  D. Durrant. Pp. 1-82, 1 figure in text. August 15, 1946.


• 
  
  • 2. The systematic status of Eumeces pluvialis Cope, and noteworthy
    records of other amphibians and reptiles from Kansas and Oklahoma. By
    Hobart M. Smith. Pp. 85-89. August 15, 1946.
  
  
  • 3. The tadpoles of Bufo cognatus Say. By Hobart M. Smith. Pp. 93-96,
    1 figure in text. August 15, 1946.
  
  
  • 4. Hybridization between two species of garter snakes. By Hobart M.
    Smith. Pp. 97-100. August 15, 1946.
  
  
  • 5. Selected records of reptiles and amphibians from Kansas. By John
    Breukelman and Hobart M. Smith. Pp. 101-112. August 15, 1946.
  
  
  • 6. Kyphosis and other variations in soft-shelled turtles. By Hobart
    M. Smith. Pp. 117-124, 3 figures in text. July 7, 1947.
  
  
  • *7. Natural history of the prairie vole (Mammalian Genus Microtus).
    By E. W. Jameson, Jr. Pp. 125-151, 4 figures in text. October 6, 1947.
  
  
  • 8. The postnatal development of two broods of great horned owls
    (Bubo virginianus). By Donald F. Hoffmeister and Henry W. Setzer. Pp.
    157-173, 5 figures in text. October 6, 1947.
  
  
  • 9. Additions to the list of the birds of Louisiana. By George H.
    Lowery, Jr. Pp. 177-192. November 7, 1947.
  
  
  • 10. A check-list of the birds of Idaho. By M. Dale Arvey. Pp. 193-216.
    November 29, 1947.
  
  
  • 11. Subspeciation in pocket gophers of Kansas. By Bernardo Villa
    R. and E. Raymond Hall. Pp. 217-236, 2 figures in text. November 29,
    1947.
  
  
  • 12. A new bat (Genus Myotis) from Mexico. By Walter W. Dalquest and
    E. Raymond Hall. Pp. 237-244, 6 figures in text. December 10, 1947.
  
  
  • 13. Tadarida femorosacca (Merriam) in Tamaulipas, Mexico. By Walter
    W. Dalquest and E. Raymond Hall. Pp. 245-248, 1 figure in text. December
    10, 1947.
  
  
  • 14. A new pocket gopher (Thomomys) and a new spiny pocket mouse
    (Liomys) from Michoacán, Mexico. By E. Raymond Hall and Bernardo
    Villa R. Pp. 249-256, 6 figures in text. July 26, 1948.
  
  
  • 15. A new hylid frog from eastern Mexico. By Edward H. Taylor. Pp.
    257-264, 1 figure in text. August 16, 1948.
  
  
  • 16. A new extinct emydid turtle from the Lower Pliocene of Oklahoma.
    By Edwin C. Galbreath. Pp. 265-280, 1 plate. August 16, 1948.
  
  
  • 17. Pliocene and Pleistocene records of fossil turtles from western
    Kansas and Oklahoma. By Edwin C. Galbreath. Pp. 281-284. August 16,
    1948.
  
  
  • 18. A new species of heteromyid rodent from the Middle Oligocene of
    northeastern Colorado with remarks on the skull. By Edwin C. Galbreath.
    Pp. 285-300, 2 plates. August 16, 1948.
  
  
  • 19. Speciation in the Brazilian spiny rats (Genus Proechimys, Family
    Echimyidae). By João Moojen. Pp. 301-406, 140 figures in text.
    December 10, 1948.
  
  
  • 20. Three new beavers from Utah. By Stephen D. Durrant and Harold S.
    Crane. Pp. 407-417, 7 figures in text. December 24, 1948.
  
  
  • 21. Two new meadow mice from Michoacán, Mexico. By E. Raymond
    Hall. Pp. 423-427, 6 figures in text. December 24, 1948.
  
  
  • 22. An annotated check list of the mammals of Michoacán,
    Mexico. By E. Raymond Hall and Bernardo Villa R. Pp. 431-472, 2 plates,
    1 figure in text. December 27, 1949.
  
  
  • 23. Subspeciation in the kangaroo rat, Dipodomys ordii. By Henry W.
    Setzer. Pp. 473-573, 27 figures in text, 7 tables. December 27, 1949.
  
  
  • 24. Geographic range of the hooded skunk, Mephitis macroura, with
    description of a new subspecies from Mexico. By E. Raymond Hall and
    Walter W. Dalquest. Pp. 575-580, 1 figure in text. January 20, 1950.
  
  
  • 25. Pipistrellus cinnamomeus Miller 1902 referred to the Genus
    Myotis. By E. Raymond Hall and Walter W. Dalquest. Pp. 581-590, 5
    figures in text. January 20, 1950.
  
  
  • 26. A synopsis of the American bats of the Genus Pipistrellus. By
    E. Raymond Hall and Walter W. Dalquest. Pp. 591-602, 1 figure in text.
    January 20, 1950.
  
  
  • Index. Pp. 605-638.
  
  


• *Vol. 2. (Complete) Mammals of Washington. By Walter W. Dalquest. Pp.
  1-444, 140 figures in text. April 9, 1948.


• Vol. 3. *1. The avifauna of Micronesia, its origin, evolution, and
  distribution. By Rollin H. Baker. Pp. 1-359, 16 figures in text. June 12,
  1951.


• 
  
  • *2. A quantitative study of the nocturnal migration of birds. By
    George H. Lowery, Jr. Pp. 361-472, 47 figures in text. June 29, 1951.
  
  
  • 3. Phylogeny of the waxwings and allied birds. By M. Dale Arvey. Pp.
    473-530, 49 figures in text, 13 tables. October 10, 1951.
  
  
  • 4. Birds from the state of Veracruz, Mexico. By George H. Lowery, Jr.
    and Walter W. Dalquest. Pp. 531-649, 7 figures in text, 2 tables. October
    10, 1951.
  
  
  • Index. Pp. 651-681.
  
  


• *Vol. 4. (Complete) American weasels. By E. Raymond Hall. Pp. 1-466,
  41 plates, 31 figures in text. December 27, 1951.


• Vol. 5. 1. Preliminary survey of a Paleocene faunule from the Angels
  Peak area, New Mexico. By Robert W. Wilson. Pp. 1-11, 1 figure in text.
  February 24, 1951.


• 
  
  • 2. Two new moles (Genus Scalopus) from Mexico and Texas. By Rollin H.
    Baker. Pp. 17-24. February 28, 1951.
  
  
  • 3. Two new pocket gophers from Wyoming and Colorado. By E. Raymond
    Hall and H. Gordon Montague. Pp. 25-32. February 28, 1951.
  
  
  • 4. Mammals obtained by Dr. Curt von Wedel from the barrier beach of
    Tamaulipas, Mexico. By E. Raymond Hall. Pp. 33-47, 1 figure in text.
    October 1, 1951.
  
  
  • 5. Comments on the taxonomy and geographic distribution of some North
    American rabbits. By E. Raymond Hall and Keith R. Kelson. Pp. 49-58.
    October 1, 1951.
  
  
  • 6. Two new subspecies of Thomomys bottae from New Mexico and Colorado.
    By Keith R. Kelson. Pp. 59-71, 1 figure in text. October 1, 1951.
  
  
  • 7. A new subspecies of Microtus montanus from Montana and comments on
    Microtus canicandus Miller. By E. Raymond Hall and Keith R. Kelson. Pp.
    73-79. October 1, 1951.
  
  
  • 8. A new pocket gopher (Genus Thomomys) from eastern Colorado. By E.
    Raymond Hall. Pp. 81-85. October 1, 1951.
  
  
  • 9. Mammals taken along the Alaskan Highway. By Rollin H. Baker. Pp.
    87-117. 1 figure in text. November 28, 1951.
  
  
  • *10. A synopsis of the North American Lagomorpha. By E. Raymond Hall.
    Pp. 119-202. 68 figures in text. December 15, 1951.
  
  
  • 11. A new pocket mouse (Genus Perognathus) from Kansas. By E. Lendell
    Cockrum. Pp. 203-206. December 15, 1951.
  
  
  • 12. Mammals from Tamaulipas, Mexico. By Rollin H. Baker. Pp. 207-218.
    December 15, 1951.
  
  
  • 13. A new pocket gopher (Genus Thomomys) from Wyoming and Colorado. By
    E. Raymond Hall. Pp. 219-222. December 15, 1951.
  
  
  • 14. A new name for the Mexican red bat. By E. Raymond Hall. Pp.
    223-226. December 15, 1951.
  
  
  • 15. Taxonomic notes on Mexican bats of the Genus Rhogeëssa. By E.
    Raymond Hall. Pp. 227-232. April 10, 1952.
  
  
  • 16. Comments on the taxonomy and geographic distribution of some North
    American woodrats (Genus Neotoma). By Keith R. Kelson. Pp. 233-242. April
    10, 1952.
  
  
  • 17. The subspecies of the Mexican red-bellied squirrel, Sciurus
    aureogaster. By Keith R. Kelson. Pp. 243-250, 1 figure in text. April 10,
    1952.
  
  
  • 18. Geographic range of Peromyscus melanophrys, with description of
    new subspecies. By Rollin H. Baker. Pp. 251-258, 1 figure in text. May 10,
    1952.
  
  
  • 19. A new chipmunk (Genus Eutamias) from the Black Hills. By John A.
    White. Pp. 259-262. April 10, 1952.
  
  
  • 20. A new piñon mouse (Peromyscus truei) from Durango, Mexico.
    By Robert B. Finley, Jr. Pp. 263-267. May 23, 1952.
  
  
  • 21. An annotated checklist of Nebraskan bats. By Olin L. Webb and J.
    Knox Jones, Jr. Pp. 269-279. May 31, 1952.
  
  
  • 22. Geographic variation in red-backed mice (Genus Clethrionomys) of
    the southern Rocky Mountain region. By E. Lendell Cockrum and Kenneth L.
    Fitch. Pp. 281-292, 1 figure in text. November 15, 1952.
  
  
  • 23. Comments on the taxonomy and geographic distribution of North
    American microtines. By E. Raymond Hall and E. Lendell Cockrum. Pp.
    293-312. November 17, 1952.
  
  
  • 24. The subspecific status of two Central American sloths. By E.
    Raymond Hall and Keith R. Kelson. Pp. 313-317. November 21, 1952.
  
  
  • 25. Comments on the taxonomy and geographic distribution of some North
    American marsupials, insectivores, and carnivores. By E. Raymond Hall and
    Keith R. Kelson. Pp. 319-341. December 5, 1952.
  
  
  • 26. Comments on the taxonomy and geographic distribution of some North
    American rodents. By E. Raymond Hall and Keith R. Kelson. Pp. 343-371.
    December 15, 1952.
  
  
  • 27. A synopsis of the North American microtine rodents. By E. Raymond
    Hall and E. Lendell Cockrum. Pp. 373-498, 149 figures in text. January 15,
    1953.
  
  
  • 28. The pocket gophers (Genus Thomomys) of Coahuila, Mexico. By Rollin
    H. Baker. Pp. 499-514, 1 figure in text. June 1, 1953.
  
  
  • 29. Geographic distribution of the pocket mouse, Perognathus
    fasciatus. By J. Knox Jones, Jr. Pp. 515-526, 7 figures in text. August 1,
    1953.
  
  
  • 30. A new subspecies of wood rat (Neotoma mexicana) from Colorado. By
    Robert B. Finley, Jr. Pp. 527-534, 2 figures in text. August 15, 1953.
  
  
  • 31. Four new pocket gophers of the genus Cratogeomys from Jalisco,
    Mexico. By Robert J. Russell. Pp. 535-542. October 15, 1953.
  
  
  • 32. Genera and subgenera of chipmunks. By John A. White. Pp. 543-561, 12
    figures in text. December 1, 1953.
  
  
  • 33. Taxonomy of the chipmunks, Eutamias quadrivittatus and Eutamias
    umbrinus. By John A. White. Pp. 563-582, 6 figures in text. December 1,
    1953.
  
  
  • 34. Geographic distribution and taxonomy of the chipmunks of Wyoming. By
    John A. White. Pp. 584-610, 3 figures in text. December 1, 1953.
  
  
  • 35. The baculum of the chipmunks of western North America. By John A.
    White. Pp. 611-631, 19 figures in text. December 1, 1953.
  
  
  • 36. Pleistocene Soricidae from San Josecito Cave, Nuevo Leon, Mexico.
    By James S. Findley. Pp. 633-639. December 1, 1953.
  
  
  • 37. Seventeen species of bats recorded from Barro Colorado Island,
    Panama Canal Zone. By E. Raymond Hall and William B. Jackson. Pp. 641-646.
    December 1, 1953.
  
  
  • Index. Pp. 647-676.
  
  


• *Vol. 6. (Complete) Mammals of Utah, taxonomy and distribution.
  By Stephen D. Durrant. Pp. 1-549, 91 figures in text, 30 tables. August 10,
  1952.


• Vol. 7. *1. Mammals of Kansas. By E. Lendell Cockrum. Pp. 1-303, 73
  figures in text, 37 tables. August 25, 1952.


• 
  
  • 2. Ecology of the opossum on a natural area in northeastern Kansas.
    By Henry S. Fitch and Lewis L. Sandidge. Pp. 305-338, 5 figures in text.
    August 24, 1953.
  
  
  • 3. The silky pocket mice (Perognathus flavus) of Mexico. By Rollin H.
    Baker. Pp. 339-347, 1 figure in text. February 15, 1954.
  
  
  • 4. North American jumping mice (Genus Zapus). By Philip H. Krutzsch.
    Pp. 349-472, 47 figures in text, 4 tables. April 21, 1954.
  
  
  • 5. Mammals from Southeastern Alaska. By Rollin H. Baker and James S.
    Findley. Pp. 473-477. April 21, 1954.
  
  
  • 6. Distribution of some Nebraskan Mammals. By J. Knox Jones, Jr. Pp.
    479-487. April 21, 1954.
  
  
  • 7. Subspeciation in the montane meadow mouse, Microtus montanus, in
    Wyoming and Colorado. By Sydney Anderson. Pp. 489-506, 2 figures in text.
    July 23, 1954.
  
  
  • 8. A new subspecies of bat (Myotis velifer) from southeastern
    California and Arizona. By Terry A. Vaughn. Pp. 507-512. July 23, 1954.
  
  
  • 9. Mammals of the San Gabriel Mountains of California. By Terry A.
    Vaughn. Pp. 513-582, 4 pls., 1 fig., 12 tables. November 15, 1954.
  
  
  • More numbers will appear in volume 7.
  
  


• Vol. 8. 1. Life history and ecology of the five-lined skink, Eumeces
  fasciatus. By Henry S. Fitch. Pp. 1-156, 2 pls., 26 figs. in text, 17
  tables. September 1, 1954.


• 
  
  • More numbers will appear in volume 8.