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CALIFORNIA
nSH-GAME

tONSERVATIOM OF WILD UFE THROUGH EDUCATION^

Volume 33 San Francisco, Julv, 1947

83418

STATE OF CALIFORNIA

DEPARTMENT OF NATURAL RESOURCES

DIVISION OF FISH AND GAME
San Francisco. California

EARL WARREN
Governor

WARREN T. HANNUM
Director of Natural Resources

nSH AND GAME COMMISSION

LEE F. PAYNE, President
Los Angeles

H. H. ARNOLD, Commissioner WILLLAM J. SILVA, Commissioner
Sonoma Modesto

HARVEY E. HASTAIN, Commissioner PAUL DENNY, Commissioner
Brawley Etna

EMEL J. N. OTT, Jr.

Executive Director

Sacramento and San Francisco

CALIFORNIA FISH AND GAME

CARLTON M. HERMAN, Editor Berkeley

Editorial Board

RICHARD S. CROKER San Francisco

BRLA.N CURTIS San Francisco

JOHN E. CHATTIN Berkeley

California Fish and Game is a publication devoted to the conservation of wildlife.
It is published quarterly by the California Division of Fish and Game. All material for
publication should be sent to Dr. Carlton M. Herman, Editor, Division of Fish and
Game, Strawberry Canyon, University of California, Berkeley 4, California. Manu-
scripts should be typed, double spaced, and conform to the style of previous issues.

The articles published herein are not copyrighted and may be reproduced in other
periodicals, provided due credit is given the author and the California Division of Fish
and Game.

This publication is sent free of charge to interested persons, who may have their
names placed on the mailing list by writing to the editor. Subscriptions are for one
year and must be renewed annually. A postcard will be included with each October
issue for renewal of subscriptions. Subscribers are requested to notify the Division of
Fish and Game, University of California, Berkeley 4, California, of changes of address,
giving old address as well as the new.

California Fish and Game

"conservation of wii dmkk THROiJon education"
Voi.UMi;:;.". ISSUED JUIA' ir>, T.M7 X'». :{

TABLE OF CONTENTS

Page

Pismo Clam Increase J. A. Aplin 120

The Status of Pine Martens in California

Howard Twining and Arthur L. IIensley 1;3;J

Ecolojiv and Life History of the California Gray Squirrel

Lloyd G. Ingles 139

Ecolofiy of a Cottontail Rabbit {Sylvilagiis cmduhoni) Populalion

in Central California IIenky S. Fitch 1'}'.)

Distinctive Characters of the Species of Andromous Trout and

Salmon Found in California Lko Siiapovaluv 185

Notes — Rare Fishes Taken Near Los Angeles John E. Fitcli 101

In Memoriam 193

John II. Davis Samuel llittcki)is 103

George Neale J. S. Hunter 194

Walter R. Krukow E. L. Maccnday 194

Reports 195

(127)

83418

PISMO CLAM INCREASE '

T'.y J. A. AiM.iN

Bureau of Ufarine Fisheries
Colifoniia Jticinioii of Fixh and (Innw

Begrinning in 1919 a systematic survey of the Pismo clams (Tivela
stultoruni), on the beach near the town of Pismo has been made each year
by the Bureau of Marine Fisheries. The first portion of this study was
carried out by Weymouth (1923). Later additions were made by Her-
rington (1930) and other members of tlie stall' of the California State
Fisheries Laborator^^ The present article adds information gathered since
the last report and indicates the present conditon of the clam population.

Each year sections have been made across the beach in three locations
some distance apart. The section consisted of a trench 16 centimeters
wide and 20 centimeters deep made across the beach and extending from
high tide to as low as it was possible to dig during one of the lowest
tides of the year. The sand from this trench was forced through a screen
of one-fourth inch mesh to make sure no small clams would be missed.
The locations of these sections were 100 yards north of the pier at Pismo
(Pismo section), 1.1 miles south of the pier (Oceano section), and one-
half mile south of the north boundary of the clam refuge (Le Grande
section). The number of clams taken in these three sections are given
by age groups in Table 1. Data for the period 1942 to 1945 are missing
as there was insufficient staff available to carry on this work during the
war. Although the total number of clams found in 1946 was greater

TABLE 1

Number of Clams by Age Groups Taken in the Three Sections
Dug Each Year on Pismo Beach

Age in Tears

Year O I II III IV V VI VII VII+ Total

1925 23 265 6 17 5 5 7 328

192fi 5.-^ 15 87 3 5 1 1 165

1927 38 61 27 23 1 l.'iO

1928 6 32 40 24 15 117

1929 472 5 23 23 15 7 545

1930 360 188 5 4 6 4 3 570

19.31 885 157 58 2 3 3 1 1,109

19.32 44 277 125 99 28 3 2 578

1933 199 38 122 99 110 52 25 2 647

1934 1 70 23 81 81 31 8 4 1 300

1935 770 6 57 15 69 41 23 6 2 989

1936 144 368 3 45 9 56 28 17 12 682

1937 747 102 247 8 19 7 32 15 2 1,179

19.38 9 233 96 175 7 11 9 6 2 548

19.39 24 4 54 75 143 2 5 4 7 318

1940 25 34 11 19 29 85 11 8 30 252

1941 19 6 7 1 2 6 23 3 13 80

1946 607 167 57 204 220 51 21 8 13 1,348

1 Submitted for publication, March, 1947.

(129)

130 CALIFORNIA FISH AND GAME

than in any previous year in which a census was taken there is no reason
to believe that the clam population is near the total that the beach could
support. Reports of persons who were on the beach before extensive
digging had depleted the natural stock state that once there were many
more clams on the beach than at present. Beaches at other locations
where these clams are found also indicate that the saturation point has
not been reached at Pismo.

As has been pointed out in former publications and is evident from
Table 1, the number of young clams less than a year old, 0 age, is quite
variable. In some years sets have been heavv, in others very sparse.
Outstanding sets occurred in 1929, 1930, 1931, 1935, 1937, and 1946.
In the years 1928, 1934, and 1938 the numbers of young clams were
negligible. It would appear that the size of any year's spawning is not
mainly determined by the number of adult spawning clams on the beach.
The good sets of 1929 to 1931 followed an interval when the number of
clams of all sizes was at low ebb, whereas the poor sets of 1934 and 1938
and the mediocre sets of 1939 to 1941 followed years when mature adults
were again plentiful.

The variation in the number of mature adults is shown more clearly
in Table 2. Here are listed by sections the total numbers of clams four
years and older found each year in which a sample was taken since 1925.
Following the good sets of 1929 to 1931 the number of adult clams
reached a peak in 1933, remained at a fairly high level through 1936, and
then decreased to low level in 1938. Good sets in 1935 and 1937 again
produced increases in 1939 and 1940. This correlation between the
numbers of adults in a population and the success or failure of spawn
survival is characteristic of a population exposed to heavy exploitation
by man. Such is true of the Pismo clam where individuals are removed

TABLE 2

Number of Clams Four Years and Older Found in Each Section

Dug on Pismo Beach

Section
year Pismo Oceano Le Orande Total

id2r, 4

1926 0

1927 0

1928 12

1929 11

19.30 2

19.31 2

19.32 1.5

19.33 80

1934 53

1935 47

19.36 24

19.37 1.5

1938 15

19.39 91

1940 50

1941 9

1946 169

Average 33.3 20.6 28.5 82.4

189

125

141

122

161

163

313

FISMO CLA.M INTREASI': lijl

from the beach as soon as they have reached the lef^al size of 127 centi-
meters (five inches) and in many instances Ix^fore that time.

Tlie lai-^e nnmber ol" clams I'onnd in ]fJ4G is of special interest since
the increase occurs not oidy amonj? the 0 group clams but also among
the larger older clams. The numbers of three- and four-year olds were
greater than at any time in the previous 17 years in which a census was
made. Part of this increase may result from good sets in 1 942 and lIM.'i but
if that were the only cause those sets would liave had to have been greater
than any previously known. It seems reasonable to assume, therefore, that
part of the increase was brought about by decreased digging during the
war years. For defense reasons the public was not allowed on the beaches
at night and fewer people were able to take annual vacations or to travel
any distance when a vacation was possible.

An 18-year average of the number of clams over age three is given
by sections in Table 2. Since 1933 the numbers of older clams have
increased as the result of several successful spawnings. For the combined
sections the 1946 total is more than three times the average. "With the
exception of 1933, in none of the previous years has the total reached
twice the average. For the Pismo and Oceano sections the 1946 numbers
exceeded the average by 5 and 3-| times respectively. In the Le Grande
section the increase was slightly more than twice the average. This
section lies in an area closed to clam digging and should not reflect an
increase in the number of older clams which might have occurred wdth
less digging during the war. These differences between the open and
closed portions of the beach further suggest that the large number of
clams found in 1946 resulted to some extent at least from protection
afforded the beach during the war. It will be of interest to determine
how long this larger population can be maintained, especially as the
number of people visiting the beach is increasing each year.

A parallel increase of the Pismo clams has been noted during the
fall and wdnter of 1946-47 on the beaches in the neighborhood of Long
Beach and Seal Beach. These clams, however, comprise younger indi-
viduals of less than four years. No census has been made in this area but
presumably the increase has resulted from good protection during the
war when diggers could not frequent the beaches.

References

Herrington, William C

1930 The Pismo Clam, Further Studies of Its Life History and Depletion.
California Division of Fish and Game, Fish Bulletin No. 18, 67 pp., IG figs.

Weymouth, Frank W.

1923 The Life History and Growth of the Pismo Clam {Tivela stidtortim Mawe).
California Division of Fish and Game, Fish Bulletin No. 7, 120 pp., 15 figs.,
18 graphs.

2 — 83418

THE STATUS OF PINE MARTENS
IN CALIFORNIA '

By Howard Twining and Arthur Hknslky

Bureau of dame Conservation

California Division of Fish and Game

The pine marten, also called American sable by virtue of its close
relationship to the rare and valuable sable of the Old World, is much
sought by a few hardy trappers in the higher mountains of California.
The marten has a body about the size of a slender house cat, and like
other members of the weasel family, to which it is affiliated, it has short
legs. The tail is bushy and the head broad, tapering sharply to a pointed
nose. It is rich golden-brown in color except for a vivid orange patch on
the throat and chest. Furriers work the skins into scarves and neckpieces
or occasionally use them as trimming for high quality coats and wraps.
Marten fur usually sells for two or three times the price of mink.

Grinnell, Dixon and Linsdale (1937) describe two subspecies of
pine marten from California : the Sierra Nevada pine marten (Maries
caurina sierrae), which occurs in the Sierra Nevada and Cascade Moun-
tains and across to the Trinity, Salmon and Marble Mountains; and the
Humboldt pine marten (M. c. humholdtensis), a slightly smaller and
darker subspecies found in the northern Coast Eanges of California
(Fig. 40).

If the pine marten were a denizen of the lowlands of California, its
valuable pelt would presumably have encouraged too-intensive trapping,
resulting in serious reduction in its numbers, much as once occurred to
the beaver and sea otter. Its haunts, however, are the forests of the
higher mountains and the rockslides and moraines of the Arctic-alpine
zone. Roads into marten country are usually blocked by snow during
trapping season and a marten trapper must be equipped to live in a
rigorous climate and usually to trap in steep, rugged country. Conse-
quently, much marten country is not trapped and the species has been
able to survive.

For many years some fur buj-ers, trappers, and other people inter-
ested in the welfare of the fur-bearing animals of California have been
concerned over an apparent scarcity of martens and have recommended
complete protection for the species in California. Another recommenda-
tion made by certain trappers was that the season on marten be shortened
in order to protect the females which, they said, run more in January
and Februarj^ and thus are more liable to be caught at this season.

In order to study the advisability of putting the above two recom-
mendations into effect, a study of pine martens was included as part of
a general survey of the fur resources of California.^

Among those who have favored a closed season on marten in Cali-
fornia are Grinnell, Dixon, and Lindsdale (1937, p. 206), who state:

1 Submitted for publication March, 1947.

2 Federal Aid in Wildlife Restoration, Project California 5-R. A Survey of the Fur
Resources of the State of California.

(133)

134

CALIFORNIA PISH AND GAME

''Reports of the trappers of California show a marked decline, amounting
to fully 75 percent, in the number of martens trapped in a four-year
period. The reported catch for each of these years is as follows: 1930,
452 ; 1921, 227 ; 1923, 137 ; 1924, 121. This decrease is not believed to be

Figure 40. Map showing distribution of pine martens in California,
and area closed to trapping

a part of any natural periodic fluctuation such as has been reported of
this and other mammals elsewhere, because the data at hand indicates
that the number of martens living in a general area in California usually
does not vary much from year to year ; on the contrary, it is probably
caused hy overtrapping. If this species continues to decline in numbers,
and if efforts are not made to give it more adequate protection, in a short
time it will be scarce or entirely absent in the State except in such
protected areas as national parks."

PINE MARTKNS IN CALIKORNIA 135

The catch records (piotcd jiltovc wci-c lakcii from reports that licoused
trappers arc required to make animully to the; ('alifoniia T'lsh and (Jame
Commission. A comparison of the al)ove fij^ures witli those received for
the five years previous to the termination of tliis study seems sij,'tiificant :

Year lU.H /H3S lU.V) l'.)',n l'J',l 19 ',2

Number marten trapped 1120 200 '2'.)~> f.lO loij ',r.'.

If, as the above-mentioned authors assume, catcii records can be
relied upon to indicate the status of an animal population it would seem
that the marten population as a wliole recovered from its temporary
condition of depletion and t lin-c was no need Tor a stati-wldc closed season.

In the course of the study 41 marten trappers were interviewed
personally bj^ the authors. All trapjiers who caufjht marten in the winters
of 1940-41 or 1941-42 "svere furnished questionnaires aiid requested to
record their catch by sex for each month of the season. Certain trappers
had informed us that they thoup:ht their lines caught more females in
January and February because females run more in the breeding' season.
If it were found that the proportion of females in the catch rose sharply
in these months an early closiu": of the marten season might have been
recommended to protect the breeding stock.

A tabulation of results from the questionnaires (Table 1) shows
that males in the catch outnumbered females in every month of the season.
There was an exceptionally high proportion of males caught in December
of both years.

TABLE 1
Data From Marten Questionnaires

ov.

Dec

Feb.

ItO-J,l

1,1-1,2

1,0-1,1

kl-1,2

1,0-1,1

1,1-1,2

1,0-1,1 1,

1-1,2

Days trapped

_— 115

184

358

592

477

476

370

220

Marten caught

___ 26

109

Days per marten_-

___ 4.4

2.9

5.2

5.0

5.9

7.3

7.6

4.5

Male

___ 16

Female

_-_ 10

Unsexed

Males per 100 fema

les_ 160

114

229

187

124
191,0-

lis

158
19',l->,2

114

Average length of line-

. 8.7 miles

8.8 miles

Average number of traps used.

. 48

Number of tri

appers answerins

; questionnaire

. 23

Number of trappers re;

porting

their catch.

. 54

Total nunibrr

of marten repor

ted.

. 428

551

Average price

paid per

pelt by

fur

buyers.

. $15.64

$14.87

There is an unexplained peculiarity in marten breeding habits
which should be pointed out at this time. Some light is throAvn on this
by Ashbrook and Hanson (1930) who found that the mating season for
pine martens in captivity is in July and August. Further investigations
by Markley and Bassett (1942) verified these findings and set the period
of gestation at 259 to 275 days. This seems exceptionally long for an
animal the size of a marten. Further study is needed on this and related
species to clarify our knowledge of their breeding habits.

136 CALIFORNIA FISH AND GAME

The uteri of eight female marten taken in trapping season were
examined by the writer but no sign of pregnancy could be detected.
Similar observations are reported by Grinnell, Dixon and Linsdale
(1937, p. 198) and, in the case of the spruce marten and sable, by
Schmidt (1934). Evidently noticeable embrj^onic development does not
begin until late February or thereafter.

If these facts are true, namely that breeding takes place in summer,
and that noticeable embrj^onic development does not start until the next
spring, then trapping does not interfere with the breeding season nor
impose a hazard on the females heavy with young.

Markley and Bassett (1942) found that marten differ in their mating
habits from other members of the weasel family in that mating does not
take place until the female is over a year old, and in over 50 percent of
the cases not until the age of two or three years is reached. The size of
the average marten litter is only three as compared with five or six for
mink. It can be expected then that this low reproductive potential would
result in slow recovery of a depleted stock.

In the course of the study particular attention was given to the
status of the Humboldt pine marten of northwestern California. Trap-
pers told us that martens in former days ranged as far south as Hull
Mountain in Lake County and Fort Ross in Sonoma County. Martens
have not been taken in Lake or Sonoma Counties for many years and
recent records are scarce from Mendocino County. A few martens remain
on the high ridges of Humboldt and Del Norte Counties and the occa-
sional trapper willing to fight heavy brush and down timber in remote
country can occasionally catch one. In 1941 the six trappers who took
martens in these counties caught an average of two apiece. In 1942 the
eight trappers who took martens in these counties caught an average of
two martens apiece.

This apparent depletion of the Humboldt pine marten in the coastal
ranges prompted a recommendation to the Fish and Game Commission
that the season be closed in this vicinity. Accordingly, in 1946 the com-
mission closed the season on pine marten in District No. 1|, which includes
all or parts of Del Norte, Humboldt, Siskiyou, and Trinity Counties.
(Fig. 40.) Very few trappers will be affected by this closure and if it
results in the repopulation of the depleted marten range the regulation
will have served a worthy purpose.

Summary

1. The pine marten is found in the higher mountains of California ;
its valuable fur encourages trappers to seek it in the remote country
where it lives.

2. People interested in the welfare of fur bearers have made two
recommendations for management of marten : (1) that the marten season
be closed in California, (2) that the season be closed early in order to
protect the females which they believed are caught in greater numbers
in January and February.

3. Results of an examination of trapping records of past years plus
. a series of 41 interviews with marten trappers indicated that the marten

population except in the north coast portion has not suffered serious
depletion in California. A state-wide closed season is not recommended.

PIXE MARTKNS IN CALIFORNIA 137

4. Infonnatioii Irum (lucstioiiiiaircs shows that males in tiie catch
outnninber fcmalos in every montli of the season. Tlio inatinj^ season for
marten is in -)nl\' and August. Noticeable embryo deveU)i)mcnt does not
start until after February. Early closin'4 of the season for pine marten
is not reconnnonded.

5. A shrinkiiij;' of llic orii^inal ran^e of tlic Iliinihohll pine inarttMi
of the Coast Ranges in northwester] i California was indicated and reports
of catch suggested depletion of the marten popidation in this area.

6. Upon the recommendation of this project the Fisli and Game
Commission in 1946 closed the season on pine marten in District li
(Del Norte, Humboldt, Siskiyou, and Trinity Counties).

References

Ash brook, Frank (i. and Karl B. Hanson.

1927. Breeding martens in captivity. Journal of Heredity, vol. 28, no. 11, \>yi.
499-503.

Grinnell, Joseph, Joseph Dixon and .lean M. Linsdale.

1937. Fur-bearing mammals of California. Their natural history, systematic status,
and relations to man. In 2 vols. Vol. 1, XII -r 37"> pp. I^niversity of California
Press, Berkeley.

Markley, Merle H. and Charles F. Bassel t.

1942. Habits of captive marten. American Midland Naturalist, vol. 28, no. 3,
pp. 604-616.

Schmidt, Fritz.

1934. Uber die Fortpflanzungsbiologie von sibirishem Zobel (Martes zibelliua L.)
und europaischem Baummarder (Martes martes L.). Zeitschrift fur Saugetierkunde,
vol. 9, pp. 392-403, 7 figs.

Walker, Ernest P.

1929. Evidence on the gestation peri(.d of martens. Journal of Mammalogy, vol. 10,
no. 3, pp. 206-209. 1 pi.

ECOLOGY AND LIFE HISTORY OF THE
CALIFORNIA GRAY SQUIRREL

J.i.oYi) (J. l.\(ii.i;s
Professor of Zooloi/i/, Fresno Stulc i'ollvgc, Fresno, California

The gray squirrel (Sciurus (friscus Ord) in California inhabits
forested areas west of the Sierra Nevada divide from Oregon to Lower
California. There are three subspecies within the boundaries of the State ;
anthonyi, in the Southern California mountains; 7iigripes, in the coast
belt south of San Francisco Bay to San Luis Obispo County ; and rjriseus,
over the Sierra and in the Coast Kanges north of San Francisco Day.

This squirrel is found chiefly within the Upper Sonoran and Tran-
sition life zones, extending locally into the lower Sonoran and up into
the Canadian. In spite of the wide distribution of this squirrel only a
few life history and ecology references occur in the literature. The present
paper records data gathered during a six-year period between November,
1940, and July, 1946, on the subspecies griseus.

Areas Studied

Many observations were made throughout the State w'ithin the
range of the species, but most of the work was done in Butte County,
particularly in Bidwell Park near Chico. This park comprises 2,400 acres
of naturally wooded land along Big Chico Creek, and extends from the
floor of the Sacramento Valley well up into the foothills. The park lies
in the Lower Sonoran and is characterized by virginal growths of such
trees as western sycamore (Platanus racemosa), Fremont cottonwood
{Populus fremontii), valley oak {Qnercus lohata), and California black
walnut {Juglans hindsii). In this life zone the two latter trees furnish
the greater part of the food of the squirrels. Certain botanists claim the
black walnuts were introduced into this area by the early settlers, but
there is considerable evidence that they became established around
certain old Indian camps long before the advent of the white man. In
the foothills the park lies in the Upper Sonoran life zone, and trees are
not nearly so dense as they are in lowland groves of valley oaks, syca-
mores, and cottonwoods. Important foothill trees include the digger
pine {Pinus sahiniana), blue oak {Qucrcns douglasii), interior live oak
{Quercus wislizenii), and scrub oak {Quercus dumosa).

In other counties, most of the observations were made at different
places in the transition life zone where chief food trees were yellow pine
{Pinus ponderosa) , white fir {Abies concolor), Douglas fir {Pseudotsiiga
taxifolia), sugar pine {Pinus lamhertiana), big tree {Sequoia gigantea),
redwood {Sequoia sempervirens) , and California black oak {Quercus
kelloggii).

Methods

The time-area method of Goodrum (1940) was used, with slight
adaptations to fit local conditions, to ascertain populations of squirrels.
The observer carried at all times a good pair of 8 x 30 binoculars and

(139)

140

CALIFORNIA FISH AND GAME

any seemingly significant observations were recorded on the spot. A 6.31
acre area was selected in Bidwell Park for special intensive daily study
during March and April, 1945. Here natural food-producing trees were
supplemented by certain introduced species. The area was surveyed and
all important trees were located on a map with the aid of a plane table.
Eight mature gray squirrels were determined by markings distinguish-
able with binoculars, and their activity on the area was followed daily.

s-"^

FiGUKE 41. A riparian association of valley oaks (Quercus lobata) , western syca-
mores (Plalanvs raceomosa) , California black walnut (Juglans hindsii) , and California
wild grapes {Vitis calif ornica) , in the Sacramento Valley which supports a large popu-
lation of California gray squirrels.

CALIFORNIA QUAY SQUIRREL

141

The individual liome ranp:os of tliose sfjuiiTols and tlic tcrritorios of two
of them were plotted on the map. Tlie areas of the liome ranj,'es and ter-
ritories were computed with ;i phuiinieter. The home range and terri-
torial concepts used in this study are essentially those described by
Burt (^943). Outlines of the liome raniafes and territories were repre-
sented by connecting points on the periphery of each of the areas. This
representation, as Burt pointed out, indicates slightly more or le.ss than
the actual area. Observation trips were made at various times of the
day under varying conditions of weather, each trip lasting about one
and one-half hours. Records made when it was difficult to classify the
day as, "clear," "cloudy," or "rainy," were discarded. The Beaufort
system of indicating wind velocity was used.

Farther up stream in the park another area was selected, because
of natural conditions that prevailed, for a study of habitat preference
(Fig. 41). A trail closely following the stream for 1.7 miles passed
through a riparian habitat including numerous large sycamores, cotton-
woods, alders {Ahms rhonibi folia), and festoons of California wdld
grapes (Vitis calif ornica) suspended from the tops of the trees. These,
with several species of undergrowth shrubs, provided excellent nesting
sites, cover from enemies, and protection from strong winds. The return
trail paralleled the stream 200 yards distant through a pure stand of
valley oaks. In this habitat there was little undergrowth to provide cover
and wind protection, and there Avere few holes in the trees suitable for
nesting sites. In season the mast production was enormous. The method
used in making observations here was to walk slowly over the 3.4 miles
of trail, stopping at frequent intervals to look and listen.

Activity and Behavior

Seventy-four trips were made between dawn and dusk on the 6.31
acre plot in Bidwell Park during March and April, 1945. More squirrels
were seen in the early morning hours than at any other time. x\bout half
as many were observed per hour after 4 p.m. as w-ere seen per hour before
10 a.m. These findings (Table 1) differ from those reported by Goodrum
(1940) on Sciurus carolinensis, which practically ceases activity after
9 a.m. but becomes active again late in the afternoon. None of the 325
squirrel observations was made before sunup. Although 14 observation
trips extended from dawni to dusk only two squirrels were observed to

TABLE I
Daily Activity During March and April, 1945, in Bidwell Park

Squirrels oiserved from —
Sunup 10 a.m. ffp.m.to

to to sundoicn Sundown

JO a.m. ^p.«i. (aloutl p.m.) to dark

Daion to

sunup

(about 7 a.m.)

Observation trips 14

March 0

April 0

Total number of squirrels
observed per hour in each

category 0

60
65
51

38.6

60
93
63

60
19
32

0
o

142 CALIFORNIA FISH AND GAME

be active after sundown. One of these spent the night lying on a limb
after another squirrel had chased it away from a tree-hole it had
attempted to enter. Goodrum's observations regarding regular activity
of the eastern species on moonlit nights apparently do not apply to
8ciurus griseus. _ .

Although notes were kept on ecological factors that might con-
ceivably affect the behavior and population of the squirrels, weather
relationship was especially noted for the two months during which daily
observation trips were made. A Beaufort 6* was the strongest air move-
ment noted during the two months period. An observation trip in the
riparian and oak habitats during a Beaufort 6 north wind revealed five
squirrels on the ground or in the low shrubbery of the riparian habitat
where air movement could scarcely be felt. None was seen in the oak
habitat where the wind was strong, even close to the ground. The animals,
by choosing protected places, were found to be about equally active under
all conditions regardless of the wind (Table 2). Although there was no
opportunity to observe behavior in very strong wind, there was no
noticeable reduction in activity in winds of moderate velocity as described

by Goodrum (1940).

TABLE II

Response to Weather

During

arch and Apri

1, 1945

Clear

Cloudy

Rainy

Wind
Beaufort
0-4*

Wind
Beaufort

4-6*

Observation trips 46

Squirrels observed 156

Average squirrels per trip — 3.4

11
54
4.9

10
30
3.0

66
329
4.5

12
36
3.0

A few more squirrels were seen on cloudj^ days than on a correspond-
ing number of trips made on clear or rainy days (Table 2) . In the spring
months the squirrels were more active in the warm, moist, and less windy
air than immediately after the passing of a cold front.

Several squirrels were observed moving about in moderate rain
storms. They frequently jumped, shaking the feet and tail to free them
from water. When eating in the rain they curl the tail up over the head
and body in such a way that the water runs off the long tail hairs without
wetting the animal. After being active in rain or morning dew they lick
themselves extensively before retiring into a nest.

Although the California gray squirrel may be active at any time
between sunup and sundown, there may also be long periods of rest
during the day. Resting periods are usually taken in a tree-hole. On very
hot days the animals become noticeably less active. They were frequently
seen spread out on some shady limb with the legs and tail hanging over
the edges, and the chin resting on the limb. Gray squirrels usually retire
to a tree-hole at night. Except when the young are in the drays, it is
doubtful if outside nests are used for nocturnal sleeping. When asleep a
captive squirrel lay on its side with its nose and forefeet pressed lightly
against its lower abdomen with the large tail spread over all the body.
It was difficult to awaken this animal.

*A classification of wind velocities: Beaufort 4 — 13-18 miles per iiour ; Beau-
fort 5 — 19-24 miles per hour; Beaufort 6 — 25-31 miles per hour.

CALIFORNIA GRAY SQUTRRF.L 143

There was considcral^Ie opjjorl unity lo observe the acuity of the
senses and behavior of the California f?ray squirrel. A younj^ captive
squirrel taken from the nest shortl}^ after llie eyes were open exhibited
manj'- interesting- traits of boliavior. Apparently this animal could not
see even though the eyes were open, for it located the me<licine dropper
with which it was fed by trial and error movements with forefeet and
head and possibly by smell. Later an opacjueness developed in the cornea,
and it became obviously blind. It could hear a whistle and woidd cease
activity for a short time when the sound was made. "When the dropper
was removed for refilling the squirrel would utter a nasal ku-ku-ku-ku-ku
until it began to suck again.

Sense of sight is only fairly keen in gray squirrels. On one occasion
the writer attracted the attention of an animal at a distance of 5U yards
by waving his arms. Strange motionless objects in the home range are
frequently seen at a distance of as much as 50 feet. Sense of smell seems
fairly well developed. Squirrels were observed on several occasions to
come to the ground and, after sniffing over several square yards, dig up
walnuts that had been buried more than one and one-half inches below
the surface. Four small pebbles and a pecan were wrapped separately In
pieces of heavy paper and placed on a log under a tree frequented by the
gray squirrels. A similar set was made a the base of another tree with
two pebbles and two pecans, one of the latter being buried. Twenty-four
hours later only the papers bearing the pecans above the ground were
unwrapped, and the contents apparently taken by the squirrels. None of
the pebbles was touched.

Adult gray squirrels made at least two kinds of sounds that aid in
locating them in the dense foilage. A series of coughs or barks, uttered
rapidly at first but becoming progressively slower as the series draws to
an end, are frequently heard when an animal has been frightened or

becomes suspicious. These cha-clia--clia—clia-—cha cha calls can be

heard on quiet days for 200 yards or more. Sometimes the calls will be
given every few seconds for an hour, and, in most cases, the cause for
the alarm can not be ascertained. At the instant of giving the call one of
the front feet is audibly vibrated against the limb. Sometimes when
alarmed a squirrel will vibrate the forefeet without barking. Squirrels
may frequently be located in the woods by the noise they make while
gnawing. A squirrel gnawing on a black walnut can be heard at a distance
of 75 yards.

Although gray squirrels are almost never found away from a tree
in the areas studied by the author, they spend a great deal of time on the
ground and may travel 250 yards before climbing a tree. Not infrequently
tree-top routes 75 to 100 yards long are used to cross streams and to get
from place to place when trees are sufficiently abundant. Although quite
at home in trees, they lack the arboreal agility of the Douglas squirrel
(Tamiasciurus douglasii). On one occasion a gray squirrel was seen to
fall from a tree by accident. The dead limb along which it ran broke just
as the animal was preparing to leap from it into a near-by tree, the
squirrel and the limb falling separately to the ground some 50 feet below.
The animal was stunned for a few seconds before it rushed to the base
of another tree and climbed it.

On the ground the gray squirrel is not a rapid runner, but will,
nevertheless, frequently pass by trees in order to reach its den tree.

144

CALIFORNIA FISH AND GAME

One animal ran through three inches of snow past many other trees a
distance of 186 feet to its den tree. One leap down a slope measured six
feet eight inches. Only once was a squirrel seen out of sizable timber;
this one was in chaparral near Tollhouse, Fresno County.

Relations to Plants

Unlike the Douglas chickaree, the California gray squirrel buries
acorns and nuts in the ground singly and never in large caches; this
practice no doubt contributing materially to reforestation. On many
occasions gray squirrels were observed to collect and bury acorns of the
valley oak outside the perimeter of the spread of the parent tree. These
acorns frequently are not recovered and, because they are in the open,
may produce healthy little trees (Figure 42). Sometimes certain small

Figure 42. Young valley oaks {Quercus lobata) growing outside the spread of
the parent trees from acorns planted by California gray squirrels in the Sacramento
Valley.

areas are favored for food storage. On one occasion 22 young black wal-
nut trees were counted mthin a 50-foot circle. The parent tree from which
the nuts were collected, presumably by the squirrels, was 152 feet away.
Probably because squirrels rarely frequent them, large acorn-bearing
oaks isolated from the rest of the woods having no such growth of young
trees outside their perimeter and rarely have any beneath them.

Sometimes gray squirrels damage certain trees either directly or
indirectly. Fritz (1932) describes damage done to young redwood trees
by gray squirrels removing the bark near the top of the tree in order to
reach the succulent layer beneath it. Grinnell and Storer (1924) pointed
out that large kitchen middens left as they husk the big sugar pine cones
at the bases of the trees may be fire hazards (Figure 43). These concen-
trations of pine scales produce hot fires which cause deep burns in the

CALIFORNIA GKAY SQUIKUEL

145

trees. However, it is very doiibti'ul whether the damaf^e done to the
forests by gray squirrels is si'^niificant.

Figure 43. A kitchen midden of the California gray squirrel at the base of
yellow pine (Fimis ponderosa) in Tulare County

Competitors

There is perhaps no aiiimal that causes the California gray squirrel
more annoyance than does its competitor, the Acorn woodpecker (Bala-
nosphyra formicivora). Not only do woodpeckers attack squirrels as they
garner acorns from the ground beneath trees in the autumn, they con-
tinue the feud about their acorn-studded trees at other seasons of the
year as well. Squirrels on the ground are sometimes attacked by two or
three woodpeckers at one time. The squirrels gain a certain amount of
protection hy carrying the large bushy tail well above the back. The
birds fly into the tail which the squirrel flicks violently. In a tree squirrels
are forced to retreat at top speed. Acorn storage trees are frequently
guarded by as many as six birds, and although they may be in a direct
tree route for the squirrels they are avoided, the squirrels going well
around or even coming to the ground in order to pass. On one occasion
two gray squirrels were digging for acorns beneath a large Digger pine
which contained thousands of acorns zealously guarded by five noisy
woodpeckers. The woodpeckers' acorns Avere all stored more than 20
feet above the base of the tree, and the birds paid no attention to the
squirrels on the ground.When one of them jumped a few feet up the tree

146 CALIFORNIA FISH AND GAME

trunk, it was vigorously attacked and pursued until it sought safety in
another tree several yards away. On another occasion three squirrels
were ' ' rushed ' ' by the writer as they were gleaning buried nuts at the
base of this same tree. Although all were within six feet of the base of
the pine, they scurried to other trees 30 to 60 feet away rather than
brave an attack by the woodpeckers. No squirrel was observed robbing a
woodpecker 's storage tree.

Another animal that causes the gray squirrel considerable discom-
fort wherever the two occupy the same area is the Douglas squirrel. It
was observed once to chase a large gray squirrel over 100 yards, largely
on the ground. At Giant Forest, Tulare County, a similar incident was
observed. It seems probable that the Douglas squirrel may limit the
upward zonal distribution of the California gray squirrel into what
would otherwise be suitable habitats.

In some places Beech ey ground squirrels (Citellus heecheyi) com-
pete with gray squirrels for food. On several occasions ground squirrels
were seen to rush at the gray squirrels when the latter came too close
to their burrows. Once a ground squirrel prevented two gray squirrels
from crossing a stream by stationing itself on a limb along the only tree
route over the stream.

Gray squirrels on the ground have been observed to take refuge
and climb trees when Oregon juncoes {J unco or eg anus) gave their
alarm calls.

The fox squirrel (Sciurus niger) and the eastern gray squirrel
{Scmrus carolinensis) , introduced several years ago from eastern states
into the cities of Sacramento, Fresno, San Francisco, and a few other
places, generally seem to be unable to leave the cities to compete with
the California gray squirrel in its native habitat, although their inability
to do so has not been proved for fox squirrels have apparently estab-
lished themselves in the woods in San Mateo County.

Predators

There are very few known cases of predators catching gray squirrels.
Near Palo Alto, Murie (1936) saw a house cat catch a mangy gray
squirrel with a nearly hairless tail. The animal was apparently weak
and sick. Near Magalia, Butte County, a large freshly killed and partly
eaten gray squirrel was found on a fallen tree about four feet off the
ground. A goshawk (Accipter gentilis) or a horned owl {Buio virgin-
ianus) seemed the most likely predator in this thick pine woods. Both
red-tailed hawks (Buteo jamaicensis) and red-shouldered hawks {Buteo
Uneatus) were observed eating Beechey ground squirrels in regions
where gray squirrels were common. It seems likely that at least young
gray squirrels would be captured occasionally by either of these hawks.
Fitch et al. (1946) found remains of two young gray squirrels in 13
red-tailed hawk nests on the United States Experimental Range in
Madera County. In two pellets out of 2,094 they found the hair of
gray squirrels.

Horned owls were occasionally seen flying at dusk in Bidwell Park
where there are many gray squirrels. Although these squirrels rarely
are active after sundown, if abroad they would certainly be vulnerable
to these large owls.

CALIFORNIA QUAY SQUIURiai 1 t7

In tl)c di*2;'jier j^ine and yellow pine assoiMutioiis, f^ray s"|iiirn'l.s
doubtless iall prey to the ^ray i'ox {Urocyon cincrcoarfjcntcus) and bob-
cat (Lynx rnfus). The coyote (Cdnis latrans) is known to eat tiieni
(Sperry, 1941). Since these squirrels spend considerable time on the
ground and are not rapid runners, they could easily be caught by these
large mammals.

Although no factual data are available, in the opinion of the writer
it is doubtful if all predators take more than a small percentage of the
number of squirrels that are annually killed by automobiles on the
highways. They seem to have no ability to recognize tlie danger of an
approaching car.

Parasites and Diseases

There is an old belief among ranchers living in the Sierra foothills
that young male gray squirrels are emasculated by the older males.
Testes were present in all males examined or observed at close range.
Seton (1928) describes instances where the dipterous parasite {Cuterchra
emasculator) destroj^s the testes of the eastern gray squirrel. Although
unidentified botflies were commonly found living under the skin of the
throats of dusky-footed wood rats (Neotoma fuscipes), on areas that
were occupied also by the California gray squirrels, none was ever
found to parasitize the latter animals.

Hubbard (1943) listed four species of fleas as parasites of this
species of gray squirrel. The most common species was Orchopeas nepos
which lives also on the Douglas sciuirrel and is found over most of the
California range of the gray squirrel. Other species were Orchopeas
latens, 0. dieteri, and Opisodasys enoplus.

The California gray squirrel is subject to devastating diseases which
occasionally reduce their numbers alarmingly. One of these diseases is
caused by scabies mite {Notoedres sp.) and is first evidenced by a scaly
or mangy appearance about the head and neck (Bryant, 1921). This
is followed by loss of hair over the rest of the body. Dead squirrels
frequently are found at the base of the trees. This disease greatly reduced
the squirrel population throughout much of its range between 1913
and 1921. In Bidwell Park, Mr. George Peterson (M.S., 1945) described
a great epidemic about 1913, "as eliminating all of the squirrels in the
2,400 acre park. ' ' According to Mr. Peterson, ' ' only a very few squirrels
remain among the digger pines out of the park on a certain hillside
near Cherokee (Butte County) 20 miles away.

That there are possibly other diseases that kill large numbers of
squirrels is indicated by the finding of eight mummified bodies showing
no evidence of scabies on June 17, 1946, on the 6.31 acre tract in
Bidwell Park that was used for the study of home ranges. Assurance
was given by a patrolman that the squirrels all died within the two weeks
previous, and that no poisoned grains had been spread for ground
squirrels. A crippled squirrel from the area was sent, on June 15, 1946,
to the Hooper Foundation for Medical Research. San Francisco, for
examination. They reported no evidence of intoxication or infection in
the specimen. Only three living squirrels were seen on the area in an
entire morning, two of which were young. The same area the year before
was the home of 11 adult animals most of which could be seen \n a
similar period of time.

3 — 83418

148 CALiIFORNIA FISH AND GAME

Food

The food wMcli tliis squirrel was seen to eat was largely seasonal,
but stored walnuts and acorns were frequently dug up and eaten even
in the spring when many other things were available. Foods that were
observed to be eaten included :

Valley oak Quercus lolata (acorns, catkins)

California black oak Quercus kelloggii (acorns)

California black -vralnut Juglans hindsii (nuts)

Pecan Carya pecan (nuts)

Almond Amygdalus communis (nuts)

Yellow pine Pinus ponderosa (nuts)

Jeffery pine Pinus ponderosa jeffreyi (nuts)

Digger pine Pinus saMniana (nuts)

Monterey cypress Cupressus macrocarpa (nuts)

Red mulberry Morus ruira (berries)

Silver maple Acer saccharinum (samaras)

American elm Ulmus americana (samaras)

Mistletoe Phoradendron flavescens (berries)

Miner's lettuce Montia perfoliata (leaves)

Common chickweed Stellaria media (flower buds)

Aphis, causing leaf roll in Oregon ash -^r " — '~~— -~-_.'-' ^

bone <^Exaxinus oregoncT^

The author obtained no evidence that the gray squirrel robs birds'
nest of eggs or young birds although they are reported to do so and they
do eat animal food. Aphids and doubtless many other insects are eaten.
The head of the femur of a sheep was gnawed by several squirrels ; after
which it was always cached in the crotch of a tree.

As pointed out previously, individual acorns and nuts are buried in
holes dug in the ground, sometimes relatively large numbers in a small
area. During fire prevention operations in Bidwell Park, a disc turned up
a number of acorns that had been buried by a squirrel recognizable to
the author by a scar on its head as one habitually occupying the area.
"Within half an hour the animal was busilv bur\dng the uncovered acorns.

Eif orts were made to determine the amounts of food eaten by squir-
rels on diffierent occasions. Another animal similarly recognized was
observed in March to eat seeds from 15 Monterey cypress (Cupressus
macrocarpa) cones, meats from five black walnuts, and a pecan, and to
graze for some time on the buds of chickweed (Stellara media). The feed-
ing period lasted for two and a half hours. Samples of these foods were
collected and weighed to ascertain the total mass consumed, which was
estimated to be 43.6 grams. In a one hour period in April the same squirrel
ate the seeds from 223 silver maple (Acer saccharinum) samaras and the
meats from two California black walnuts estimated to weigh 51.6 grams.
Two lactating female squirrels were observed on different occasions to eat
flower buds and leaves of chickweed.

On different occasions squirrels were observed to drink (without
lapping) from streams and from knot holes containing water. One was
seen to come to the ground to urinate. The oblong fecal pellets are dark
brown or black, 2-3 mm. wide by 4-5 mm. long. They are stickj^ and
sometimes adhere to the fur.

Breeding Behavior

The California gray squirrel appears to have but one rutting period
a year ; this starts in January and continues for some individuals through

CALIFORNIA GRAY SQUIRREL 149

Ma3^ The peak appears to be reached in February. However, Bailey
(1936) reported a lactatiiif,' <^i"dy .s(|iiirrel in Humboldt County on
October 30. This date may indicate two litters a year, but may also repre-
sent only a late breedin<^ younj^ female. The ruttin<^ period of tlie ^'ray
squirrel is characterized by considerable chasing by both males and
females and by the presence of one or more males in the immediate
vicinity of a female. Testicles of the males are noticeably enlarj^ed and
the scrotal sac is more darkly pigmented than the rest of the under parts.
When in oestrus, the vulva of the female is swollen and pink in color.

An actual copulation was observed late on the afternoon of March
23, 1945, in Butte County. A female, designated as No. 2, was observed
receiving the attentions of two males on March 19, 1945. On March 23,
1945 (about 5:15 p.m.), when the author entered the area the barking
of a squirrel was heard about 50 feet up in an oak. Through the glasses
this animal was identified as a male. On a nearby limb was female No. 2
licking her vulva. After several minutes the female started off by a tree
route to a walnut tree on the other side of the grove. She stopped occa-
sionally to lick her vulva. The male followed slowly about 20 feet behind,
barking softly. On reaching the walnut tree she descended it slowly until
within a few feet of the ground. When the male overtook her she would
pursue him vigorously for a few feet. After several such charges the male
rushed after her, and the two vrent round and round the trunk for several
seconds until he overtook her at the end of a small branch about 12 feet
above the ground. There was a great tussle and a flourish of tails took
place. The male mounted the female dog-like, and in a couple seconds the
copulation was completed. In the final tussle the male lost his hold and
fell to the ground. The male climbed the tree slowly, but finding the
female facing him on a small limb returned to the trunk and bit off
chunks of bark which he threw to the ground. After several minutes he
descended to the ground found a walnut, and proceeded to eat it. The
female, after licking her vulva, descended to the ground, found a nut,
and ate it.

The male gray squirrels seem to be very compatible during the
rutting season when it is not uncommon to see three or four together
but serious fights sometimes occur. Such a fight was observed in which
one of the squirrels received a badly bitten fore-paw which it favored
and licked for six days afterwards. After the fight the beaten and
wounded squirrel was pursued in a large tree for half an hour before it
escaped unseen by its pursuer to another tree. The pursuing squirrel
searched the tree in which the fight occurred before giving up the chase.

Nests

The California gray squirrel builds two kinds of nests ; those made
in tree-holes and those called drays which are built out among the
branches of the trees. Both kinds of nests were observed as they were
being built. Tree-holes are generally made by a woodpecker or flicker,
but may result from decay following the breaking off of a limb. They are
most likely to be found in oaks, cottonwoods, and sycamores. Before occu-
pation they are provided with a soft inner nest made of fibrous shredded
bark from redwoods, cedar, or pines. Usually the pieces of bark are
gathered on the ground, but on one occasion a pregnant female was
observed to collect nestbark from a redwood trunk 60 feet above ground

150 CALIFORNIA FISH AND GAME

The piece of bark wa-s held in the mouth while the claws are combed
through it to render it soft and pliable.

The outside of the dray is made of sticks about the diameter of a
pencil. Such nests are two to three feet in diameter and may or may not
be covered over. The inner nest is either made of shredded bark or fine
grass. In Chico one dray which was built in a fan palm (Washingtonia
filifera) was made entirely out of the fibrous material of the palm tree.
It weighed 271 grams and was blown from the tree during a windy day.
On one occasion a pregnant female was observed daily as she built a
dray in the top of a redwood tree. Merriam (1930) found a gray squirrel
dray built in a tan oak (LitJwcarpus densiflora) in Marin County.

Most nest building takes place in early spring before young are born ;
however, a gray squirrel was seen adding soft sequoia bark to its nest
at Giant Forest Tulare County, in September. Females were frequently
seen carrying nest material to their nests after their young were known
to have been born.

Young

The gestation period of the California gray squirrel is longer prob-
ably than six weeks. Forty-three days after a known copulation, the
obviously pregnant, marked female (described above as female No. 2)
had not given birth to young. She was not observed associated with male
squirrels after the day of copulation although she was seen daily. The
gestation period for the eastern gray squirrel is given by Goodrum (1940)
as 44 days. From the author's observations, litters range from two to
four young. Nine litters studied had one with four, four with three,
and four with two young. Young squirrels begin to make their appearance
around the nest about the middle of ]\Iarch with the greatest number
appearing about the middle of April. Young of late breeders, however,
will not appear until the middle of June even in the lowlands.

The 3"0ung of the California gray squirrel may be born any time
between February 1st and the middle of June, regardless of the life
zone. Although young squirrels v-ere frequently found in drays, some
evidence was obtained to indicate that they are not necessarily born
in these outside nests, but are carried there when they become too large
for the tree-hole nest, or when the fleas and other parasites become
intolerable in the original hom.e.

The youngest squirrels kno■v^^l belonging to this species were
reported by Storer (1922). These were taken from a dray in Marin
County on April 13, 1919. They were kept for three days. At first only
very short hairs showed dorsally on the wrinkled skin, but at the end
of the third day the lateral hairs began to show. Storer gives the weights
and measurements for these animals 48 hours after they were taken as
follows : male, 74.6 grams, total length 205 mm., tail 93 mm., hind foot
34 mm., ear 8 mm., and for the female, 80.0 grams, total length 225 mm.,
tail 95 mm., hind foot 37 mm., ear 8 mm. The youngest litter seen during
the present study occupied a dray in a palm tree in Chico. One of these
young squirrels was kept as a captive until it became full grown.
Although this yoilng female had its eyes open, as did the other three
litter mates, it was blind within a week and remained so for the rest of
its life. The most striking features about the animal were the large feet
and the very short hair on the tail (Fig. 44).

CALIFORNIA GRAY SQUIRREL

l.')!

Tliis sciuirrel was kc^jt Jii a (.-a^c and I'rd witli llic aid ol' a luiMliciiM-
dropper, milk and honey at first, and, as it became older, nuts and other
foods. It was possible to wei<»h and measure this animal ordy in the first
month after captivity; later, Avhen it was half-^n-own (adult females
average about (575 grains) it was impossible to weigh it satisractcji-ily.
The Aveights and measurements obtained are presented in Tabif; I! I.

TABLE III
Growth of a Young Gray Squirrel

Total Hind Ear

LoKjIli Tdil fool (rioiiut) W'iiflil

Mar. 10, 1045 270min. 140mm. HSmm. 10mm. 126Brams

Mar. 16 275 142 "•!) 12 l.*r>

Mar. 23 ;506 150 CO is 17!)

Mar. 31 _ _ _ _ 240

Apr. 6 _ _ _ _ 270

Apr. 13 _ _ _ - 353

Upon comparing weights of this sqnirrel with those of the litter
described by Storer (1922), which he estimated to be one week old, it
would appear that this one was about three weeks old when taken from
the nest. At this time there were several well developed instincts, a few

Figure 4 4. A young California gray squirrel approximately 3 weeks old

of which follow : It would scramble wildly with all four feet when held
about the body in such a way that it could get no hold with its claws.
It would sit squirrel-like and nibble on objects held between the forepaws

152 CALIFORNIA FISH AND GAME

even thougli it would eat only liquids. When not hungry it resented being
taken from the nest, would attempt to bite and would utter little bark-
like ''quaffs." When about two months old it would bark, flick its tail,
and vibrate its forepaw. It had no opportunity to observe any of these
beha\aor traits in other squirrels after being taken from its nest. This
squirrel was fully grown by September.

Little is known regarding the longevity of this species. Eoss (1930)
called attention to two that were kept as captives for 11 years. This pair
had a male offspring that was 8 years old. Whether they ever attain these
ages in nature is not known.

Home Range and Territory

The daily activity of the eight marked squirrels, three males and
five females, on the 6.31 acre area previously described was observed
(March and April, 1945) to ascertain the shape and size of home ranges
and territories (Figs. 41 and 42). Although nearly all of the 2400 acres
in Bidwell Park is still under natural conditions, this particular area
was not. On it were growing such introduced jDlants as almonds, Monterey
cypresses, elms, and silver maples, all of which greatly increased the
food supply and nesting sites over that provided by the native Digger
pines, valley oaks, black walnuts, alders, cottonwoods, and sycamores.
As many as 11 adult squirrels were seen on this area although part of
the home ranges of a few were just outside of it. Four litters were known
to be raised on the area at this time, and another pregnant female
established her home range there before the following May.

Male squirrels are apparently much more compatible than are the
females. The three marked males were frequently seen feeding within
a few feet of each other on the ground or in the trees.

Home ranges of females varied from .30 to .85 acres, and as a result,
there was considerably less overlapping than was the case with the home
ranges of the males which varied from 1.15 to 1.53 acres each (Figs.
45,46,47). _

Three territories defended against other squirrels were studied at
a time when the females were nursing young. Only two of these were
entirely within the area, however, and are shown in the diagrams in
relation to the home ranges (Fig. 47) . Territories of these two lactating
females were one-fourth to one-third the size of their respective home
ranges. All squirrels regardless of sex were chased from the territory
whenever they were seen by the female that occupied it. When she was
in her nest other squirrels sometimes would cautiously enter and take
food from the trees. How long the territory was defended after the
young squirrels left the nest was not determined.

CALIFORNIA GRAY SQUIRREL

153

Figure 45. The home ranges of three marked male California gray squirrels on
a 6.31 acre tract in the Sacramento Valley during March and April, 1945. Scale .25 mm.
equals one foot.

154

CALIFORNIA FISH AND GAME

Figure 46. The home ranges of five marked female California gray squirrels
occupying- at the same time the same area as shown in Figure 45. Three other unmarked
animals of undetermined sex also occupied this area during this time.

CALIFORNIA GRAY SQUIRREL 155

? 1 ? 4

Figure 47. The home ranges and territories (stippled) of two marked female
California gray squirrels in the Sacramento Valley during March and April, 1945. Scale
.25 mm. equals one foot.

There was considerable daily movement of squirrels between nesting
and loafing places, and feeding places. This was particularly noticeable
between the riparian habitat, which provided excellent nesting and
resting sites, but little food, and the pure oak stand habitat which had
plenty of food but little else. Squirrels could be found feeding in the
oak habitat fully 200 yards from the stream (or other water) at nearly
any time of the day, but when surprised they would invariably climb
a tree and take an arboreal route back to a hole or dray in the sycamores
and cottonwoods by the stream. The animals seemed to sense their greater
security in the riparian habitat and were more likely to be seen there.
Six round trips through both these habitats revealed 24 squirrels, 18 of
which were in the riparian and six in the oak habitat.

Populations

The populations of gray squirrels in California have been variously
estimated. Grinnell and Storer (1924) believed there was only about
one squirrel on each 10 acres of native range in the foothills. They
estimated the squirrel population in the Yosemite Valley to be about one
squirrel on each acre. Stanley (1916) reported gray squirrels to be com-
mon enough in the Plumas National Forest to enable one to see 30 to
40 a day.

During March and April, 1945, on the 6.31 acre area that was inten-
sively studied in Bidwell Park, there were 11 adult squirrels. At this
time four of these were known to be lactating and another was pregnant.

As was previously pointed out, this area contained several nonnative
trees that doubtless supplemented materially the food and nest sites
provided by the native trees and enabled this area to support a larger
number of squirrels than it would in a truly native state. There was at
no time insufficient squirrel food, but there was much evidence of com-
petition for nesting holes. On this small protected area predators play
a negligible part, the population being kept down by accident on a
nearb.y road and possibly by diseases which might account for the occa-
sional reduction in numbers from 75 to 100 percent, such a reduction
having been pointed out by Peterson {op. cit.).

]156 CALrPORNTA FISH AND GAME

Economic Status

Near Paradise, Butte County, a nut grower reported the killing of
hundreds of gray squirrels over a period of 10 years because of the
damage they did to his English walnut grove. This grove borders a yellow
pine-white fir woods Avhere squirrels are very numerous. Almond trees
that grow on small lots in the suburbs of Chico are rarely harvested
because of squirrels and acorn woodpeckers.

The flesh of the California gray squirrel is delectable, and the
animal was formerly considered as game with an open and closed season.
It was first given a closed season in California in 1901, when the open
season extended from August 1st to February 1st. In 1905 there was
no open season, and in 1907 the season extended from September 1st
to January 1st, and the bag limit was 12. In 1923 the animal was taken
from the game list because of a serious reduction in its numbers and it
has been given protection ever since, until 1946 when the season was
again opened.

Sugg-estions for Habitat Improvement

The habitat of the gray squirrel can be improved in places where
more squirrels are desired, by planting certain trees. Western sycamore
and Fremont cottonwood provide more holes for nests than any other
trees in the lower Sonoran life zone. In the upper Sonoran life zone,
blue oak, and in the transition life zone black oak provide best nesting
sites and best food trees. Trees which may be introduced to supplement
the local native food supply are silver maple, black walnut, mulberry,
and Monterey cypress. Digger pines and yellow pines are the most
important native conifers in the upper Sonoran and the transition zones
respectively. The frequency with which the animals are found in the
vicinity of abandoned and even occupied foothill ranches attests their
adaptableness to man-made environments, especially to the food on the
ornamental and nut trees. Walnut trees grown from seeds planted along
the foothill streams throughout California would greatly, increase the
food of these animals and might be the decisive factor in maintaining
sufficient breeding population in years when the acorn or the digger pine
cone crop fails or is greatly reduced. A few nut-bearing walnut trees
close to a stream will, after a few years, establish young trees in favorable
places for miles below the original parent trees.

Summary

1. A study was made of the ecology and life history of the California
gray squirrel in some limited areas of California between 1940 and 1946.
Two areas in the valley oak association in the Sacramento Valley were
selected for daily observations on some marked animals during March
and April, 1945.

2. The daily activity and response to weather conditions was found
to differ from that described for the eastern gray squirrel. The animals
were more active in the morning than at midday or late afternoon.
Activity before sunup and after sundown was rarely observed. The kind
of weather had little effect on activity.

CALIFORNIA QUAY SQUIKRI'X 157

3. The souse of smell seorned to he fairly well developecl and used
to locate food buried in the ground. The sense of si<^dit likewise a[)[)(';irc(|
to be well developed.

4. Gray squirrels are important and beneficial animals in refor-
estation in the valley oak association not adjacent to agricultural areas.

5. The most important competitors are the acorn woodpecker,
Beechey ground squirrel, and the Douglas chickaree. Very few predators
are known. Many squirrels are killed on highways by cars.

6. Four species of fleas are known to parasitize these squirrels.
Devastating diseases apparently sometimes entirely eliminate or greatly
reduce the numbers of gray squirrels over large areas. One of these is
caused by a scabies mite.

7. The fruits of a large number of native and introduced plants are
used for food. Flower buds and leaves of chickweed are frequently eaten
by lactating females. The squirrels were rarely seen to use animal food.

8. The rut may occur any time during the first six months of the
year. Each female appears to have but one litter of two to four young
each year. The gestation period is probably over 43 days. Two kinds of
nests are built.

9. A captive young squirrel exhibited a sequence of inherited
behavior patterns as it grew older.

10. The home ranges of the males varied from 1.15 to 1.53 acres
each. These overlap greatly the ranges of other squirrels. Males are
generally compatible. The home range of individual females varied from
.30 to .85 acres. Females were generally incompatible during the breeding
months. The territories of lactating females were about one-quarter to
one-third the area of the respective home ranges.

11. The population varies with the type and amount of plant cover.
The greatest concentration noted was 11 adults living on a 6.31 acre
tract in the Sacramento Valley. By means of habitat improvement the
populations in most areas might be increased by planting certain intro-
duced trees to supplement the food during the non-producing period of
the native trees.

References

Bailey, Vernon

1936 The mammals and life zones of Oregon, U. S. Dept. Agric, Bur. Biol. Surv.
N. Amer. Fauna, No. 55, pp. 1-416, illus.

Bryant, H. C.

1921 Tree squirrels infested with scabies. California Fish and Game, San Fran-
cisco, 7 : 128.

Burt, William Henry

1943 Territoriality and home range concepts as applied to mammals. Journ.
Mammalogy,' 24 : 346-352.

Fitch. Henry S. Freeman Swenson and Daniel F. Tillotson

1946 Beiiavior and food habits of the red-tailed hawk. The Condor, 48 : 205-237.

Fritz, Emanuel

1932 Squirrel damage to young redwood trees. Journ. Mammalogy, 13 : 76.

158 CALIFORNIA PISH AND GAME

Goodrum, Phil D.

1938 Squirrel management in eastern Texas. Trans. Third North American
Wildlife Conference, pp. 670-676.

1940 A population study of the gray squirrel in eastern Texas. Texas Agri. Exper.
Sta. Bulletin, No. 591, p. 34.

Grinnell, Joseph and Tracy I. Storer

1924 Animal Life in the Yosemite. Univ. Calif. Press, pp. xviii + 741, illus.

Hubbard, C. Andresen

1943 The fleas of California. Pacific University Bulletin, Forest Grove, Oregon,
39 : 1-11.

Merriam, C. Hart

1930 A nest of the California gray squirrel (Sciurus griseus) . .Journ. Mam-
malogy, 11 : 494.

Murie, Adolph

1936 A predator eliminates a sick animal. .Journ. Mammalogy, 17 : 418.

Peterson, G.

1945 (By letter).

Ross, Ronald Case

1930 California Sciuridae in captivity. Journ. Mammalogy, 11 :76-77.

Seton, E. T.

1928 Lives of the game animals. New York: Doubleday Doran, vol. 4, Rodents,
pp. 1-949.

Sperry, Charles C.

1941 Food habits of the Coyote. Wildlife research bulletin No. 4. Fish and Wildlife
Service, pp. 1-70.

Stanley, A. J.

1916 Gray squirrels in the Plumas National Forest, California Fish and Game,
San Francisco, 2 : 112.

Storer, Tracy I.

1922 The young of the California gray squirrel. Journ. Mammalogy, 3 : 188-189.

ECOLOGY OF A COTTONTAIL RABBIT

(SYLVILAGUS AUDUBONI)

POPULATION IN CENTRAL CALIFORNIA

15y lIiONUY S. Fncii
United States Finh and Wildlife Service

The cottontail rabbit of the western Sierra Nevada foothills
(Sylvilagus auduhoni vallicola) is sufficiently abundant in some areas to
figure in the ecology and economy of the region in various ways — as a
game animal as a reservoir of disease potentially transmissible to
humans; and as a destroyer of vegetation, either cultivated crops or
forage on range lands. During the course of wildlife studies at the San
Joaquin Experimental Range, data were collected bearing on various
phases of cottontail ecology. Especially during ]939, 1940, and 1941,
many rabbits were live-trapped incidental to the trapping of ground
squirrels, and information was obtained as to their numbers and activ-
ities, and various other factors, on an 80-acre area.

The experimental range is situated in, and typical of, a foothill belt
used primarily for grazing of beef cattle. Interest in the rabbits iu this
region centers in their effect on range forage. The species is little hunted
in this part of the State, partly because other more popular small game
species are abundant, partly because it is heavily infested with fleas, and
partly because it is considered unsafe to handle since it is a carrier of
tularemia. This region is mainly open woodland of oak (Quercns dougJasii
and Quercus wislizenii) and pine (Pinus sabiniana), occasional patches
of chaparral and an annual type forage of broadleaf herbs and grasses ;
mostly it is rolling land, but there are occasional bluffs and ravines. The
soil is generally shallow and rocky ; outcrops and loose piles of decom-
posing granite rock are prominent features of the terrain. The brush
patches and rock piles provide shelter for numerous wildlife species
including the cottontail. The climate is one of mild winters and hot,
rainless summers with temperatures over 100 degrees F. Annual precipi-
tation averages approximately 22 inches.

This study was part of a program of wildlife investigation planned
and initiated by Everett E. Horn of the U. S. Fish and Wildlife Service,
in collaboration with the California Forest and Range Experiment
Station, U. S. Forest Service. Lowell Adams, Freeman Swenson, Frank
Hagarty and Bernard Mitchell helped with the live-trapping. Howaid
Twining, Daniel F. Tillotson and John E. Chattin analyzed scats and
pellets in connection with the predation phase of the work. Assistance
rendered by WPA Project No. 165-2-08-225 is acknowledged.

Methods
The rabbit population was intensively studied on an 80-acre area by
marking for future identification and releasing all that could be live
trapped. At each capture, sex, weight, catalogue number or formula, and
exact location of the animal were recorded in the field. Those taken in
1939 and 1940 were marked with serially numbered aluminum ear tags

(159)

160

CALIFORNIA FISH AND GAME

and colored celluloid disks manufactured for use by commercial rabbit
breeders ; those trapped in 1941 were marked by toe clipping. Food habits
data were obtained on this same area by following rabbits as closely as
possible recording the kind and amount of vegetation taken.

Seasonal Bait Acceptance

During 1939, 1940 and 1941, trapping effort was fairly constant
year-round ; on the 80 acres where population studies were made, approxi-
mately 200 traps were kept set for several daj^s each week. Differences
in the catch of rabbits reflected both actual changes in their number and
changing seasonal acceptance of the grain baits used. Throughout the
growing season, October through May, while green food was abundantly
available, rabbits only rarely entered the traps. It is assumed that
natural foods were much preferred to the grain mixture of wheat and
milo maize with which the traps were baited. In summer after the main
forage crop had dried out, grain was taken freely, and nearly all recorded
captures of rabbits were in the dry season — summer and early fall. The
total number of captures recorded each month during the three-year
period in which live trapping was in progress is shown in Fig. 48. Each
year the catch was highest in August at the peak of the dry season. Trends
were similar for all three years, but in 1939 bait was taken much more
readily. During the dry season that year natural food was scarce due
to the short forage crop and early drying. In 1941 the forage crop was
heavier and succulence longer persisting than in 1940, and the catch of
rabbits was correspondingly light. During the course of live trapping,

250

o/ \

'>>/ \

o/ \

"^1 \

200

1 \

150 / \

100 / \

1 oA \

/ ^/ \ \

/ CK/ \ \

/ "^Z \ \

^-^ 1^41 \ L

■ — ^><r

^^^^^^-^^^^^=====^

January February March April May June July August SeptemberOctober November December

Figure 4 8. Numbers of captures of cottontails from month to month on 80 -acre
trapping area in three different years. Trapping effort was fairly constant through the
year and the fluctuating catch reflects seasonal variation in bait acceptance.

COTTONTAIL POPULATION IHl

January Fehruary March April May June July August September October November December

Figure 49. Numbers of cottontails live-trapped on an 80-acre study ana each
month in 11)3'), 1940 and 1941. The month-lo-nionth changes in total catch are influenced
mainly by changing bait acceptance rather than by actual changes in numbers of rabbits.

the few rabbits caught in winter and spring were often individuals which
had been trapped frequently during the preceding dry season, and had
perhaps acquired a special liking for the bait used.

Movements

During the three-year period, 228 rabbits were trapped a total of
1,159 times. The different locations of capture for an individual provided
information concerning extent of foraging range, homing propensities,
and shifts in centers of activities.

Foraging Range. Numerous captures of some individuals within

a fairly short time revealed the extent of normal foraging activities or

"cruising radius." As the numbers of records on individual rabbits

increased, the foraging ranges plotted from them usually tended toward

an oval shape. In many instances diameters of foraging ranges may be

indicated by the maximum distance recorded between points of captures.

When records are few, the distance is apt to be unrepresentatively short.

For the 134 individuals each trapped at different locations on the area,

maximum distances between points of capture, "foraging diameters,"

are presented in Table 1.

TABLE 1

2 Sto5 6 to 11 11 to 21 21 or more

captures captures capttires captures capttires

Number of rabbits 27 36 39 27 5

Average of foraging

diameters in feet 451 496 723 781 1044

Extremes of foraging

diameters in feet 30-1,450 50-1,200 250-2,100 250-1,700 820-1,300

If the sexes differ in extent of home range, the difference is slight.
Females may move about somewhat less than males, but some of the
largest home ranges, plotted for individuals having many repeat records,
were those of females. The average "foraging diameter" for all females
(72) captured at more than one point was 626 feet, as against 632 feet
for the entire group of 134, including both sexes. If the distances between
captures actually represent the extent of foraging areas, home ranges
of, roughly, eight or nine acres for both sexes were indicated, but prob-
ably in most instances the areas w^ere somewhat larger. Ingles (1941:
234) wrote of this same species studied at a locality 200 miles northwest :
"The home range of a male rabbit may be as much as 15 acres since three

162

CALIFORNIA FISH AND GAME

were taken at stations 400 yards apart. The home range of a female rabbit
is often less than an acre, which may be shared with as many as four
other rabbits."

The difference may be due to the spotty distribution of food and of
shelter — scattered clumps of blackberry thickets — where Ingles' study
was made. His conclusions were based on comparatively few individuals
on a small area. The open and uniform terrain on the Experimental
Range would promote extensive movement.

Measured distances between points of capture are not entirely satis-
factory for showing home ranges. The shorter distances represent indi-

i MILE-

qs^

• •

• • 9

H40

FiGURH 50. Map showing distribution of individual cottontails live-trapped in
80-acre study area in summers of 1939, 1940. Each dot represents central point of an
individual home range. Note relative abundance in 1939, and concentration near left
margin of area where water was available.

COTTONTAIL POPULATION

163

MILE

Figure 51. Home ranges of six different cottontails on 80-acre study area, as
plotted for each from points of capture over periods of months. Three outlying points of
capture from home range in upper center evidently resulted from trips to water supply
outside usual range.

vidiials for which the records do not reveal the true extent of the areas
covered while the longer distances in some instances may represent
unusually long foraging trips, and in others possibly reflect shifts of
headquarters over periods of time. The median of "foraging diameters"
recorded, for all those with more than five captures, was 700 feet. This
distance is probably roughl}^ representative of the diameter within which
most of the activities of an individual are confined.

Several opportunities arose to watch the extent of movements of
unusually tame and easily recognizable individuals frequently encoun-
tered in the field. Two in particular were intensively observed and were
often followed in attempts to record their feeding. One of these was an
old female, the other was a young of the year slightly more than half-
grown. Both were somewhat more limited in their observed movements
than were other individuals whose ranges were revealed by trapping,
but the observations were made principally around dusk. Though activ-
ity is pronounced at that time of day, it appears that the rabbits then
tend to forage in proximity of cover, ranging more widely after dark.
Individuals were often trapped at night in areas of open grassland where
they were never seen to venture in the daylight, and droppings were also
abundant in such places.

Small young have much smaller foraging areas than have adults.
One was usually seen foraging within a few yards of some pile of rock
or brush or similar shelter into which it might dash at any alarm. Young
less than half-grown were trapped in small numbers ; usually a larger size
is reached by the time the dry season sets in rendering grain bait more
attractive than natural foods. A few young did seem to acquire a taste
for the bait earh^ in the season, and these entered traps frequently, each
always at about the same place near the edge of some covert. The rabbits
moved a good deal more widely than the ground squirrels which were
trapped on the same area.

164 CALIFORNIA FISH AND GAME

Homing. Ability to return within a short time to the home range
with which it was familiar was demonstrated by each of three rabbits -
which made homing movements of 4,400 feet, 3,550 feet, and 3,150 feetj
respectively, after being trapped and removed from the experimental]
range headquarters where cottontails were often troublesome in taking
bait set out to trap quail. Twenty others similarly trapped and removed
to the rabbit study area slightly more than three-fourths mile away, all
failed to make homing movements, apparently. Ten were never recap-
tured, and the remaining 10 were recaptured on the study area ; several
of them were taken repeatedly over long periods of months indicating
that they had settled down in the new location near where they were
released. Distances of movement from the point of release recorded for
members of this group after recapture varied from zero to 2,200 feet.

Shifts of Range. Only one clear-cut instance of shift in range, or
migration was obtained. This involved a male trapped five times within
a two-weeks period in August, 1940, when it was less than half -grown.
All these records were within an area of 450 feet diameter. The remaining
record for this animal was obtained on June 2, 1941, when it was killed
near the headquarters area, having made a movement of 3,300 feet.

The study area was not well adapted for the recording of long
movements since it was only a little wider than the maximum diameter
of a foraging area, and but twice as long. Shifts of range in most cases
would have taken the rabbits beyond its boundaries where they would
not have been recorded except by accident.

However, such shifts may be an important factor in affecting the
population turnover which is apparent from the trapping records.
Many rabbits were caught frequently over periods of weeks and then
disappeared abruptly from the records even during the dry season when
bait acceptance was still good. Perhaps most of these were actually
eliminated by predators and other causes of natural death, but some
possibly transferred their activities elsewhere.

During the dry season of 1939, forage in general, and especially
succulence and water, was unusually scarce. Near one end of the study
area, seepage in the dry creek bed, and a nearby stock trough, furnished
watering places much used by the rabbits. Trapping records that year
indicated some clustering in this part of the area, while the 1940 records
were more evenly distributed.

Further evidence of shift in foraging range to include critically
needed food or succulence was obtained at the headquarters area. Here,
two unfenced lawns were watered regularly through the summer. These
lawns were within a cleared area adjacent to roads, buildings, and a
small orchard, where rabbits were rarely seen during the green season.
But in the dry season, especially in 1939, the la^vns were exceedingly
attractive to the cottontails. Shortly before dusk they would begin to
congregate, and later in the evening a person driving up in a car would
often see as many as 30 dashing from the lawns to seek cover. It seemed
evident that most of the individuals involved had extended or actually
transferred their foraging ranges to include the area of the lawns.

COTTONTAIL POPULATION 165

Population

On tlie 80-acre area where live-1rai)j)iii^ was carried on, information
was obtained rcg-ardin<i; the poi)ulati()n density oi" cottontails, in com-
puting the numbers actually present, use was made of tlie Lincoln
Index — tlie ratio obtained in a given sampling period, of previously
marked individuals reeai)tured to all those caught, including some not
previously marked. The census i'ornuda used was as follows :

Total population of 80 acres Number caught August to December

Number caught January to July Number caught January to July and

recaptured August to Dccf.'mber

In choosing the two sampling periods necessary for the computa-
tion, most plausible figures were obtained by division into a January
to July preliminary period during which part of the population was
trapped and recorded, and an August to December post-census sampling
to obtain the ratio of the previously marked individuals to the popula-
tion as a whole. This division of periods was made to include, in each,
a part of the July-August season of maximum bait acceptance. Other
divisions in which one or both periods fell within a spring or fall season
of poor bait acceptance and few captures produced obviously distorted
census figures. The numbers trapped which were used in the census, were
as follows :

Year January to July August to December Both Periods

1939 49 78 25

1940 22 31 13

1941 49 35 18

From these figures, census computations were made as follows :

19S9 census

X 78

49 25 25x = 3722 x =^ 153 cottontail

1940 census

X 31

22 13 13x =682 x = 53 cottontail

194i census

X 35

49 18 18x = 1766 x = 95 cottontail

In each instance the figure obtained represents the number pres-
ent in early summer — a population of adults, and subadults or weU-
grown young of the year. Aside from the pronounced year-to-j^ear
fluctuations suggested by the above figures, the population, of course,
goes through an annual cycle resulting from the seasonal limitation of
breeding, but the pattern of this cycle cannot be shown with present
data. The population presumably undergoes rather gradual reduction
throughout the dry season, until it is again augmented by the annual
crop of young, perhaps several litters for each female during the course
of the breeding season. Most of these small young are rapidly eliminated
during the time they are helpless in the nest and for many weeks after-
ward while they are extremely vulnerable to predatiou.

166 CALIFORNIA FISH AND GAME

The annual Lincoln Index census probably gives a fairly accurate
approximation of the numbers present on the area. Checks were obtained
by the use of one-month sampling periods. From these censuses the fol-
lowing figures were obtained for July and August for each of the three
years.

19S9 19-',0 19',1

Julv 15P. 39 76

August 152 36 38

These are considered less accurate than the figures from the six-
month sampling periods, mainly because of the smaller numbers involved.
The August 1941 figures are considered particularly unreliable since they
were dependent upon the small and inadequate sampling in September
of that year when bait acceptance was poor.

Even assuming that the actual census figures obtained are an
accurate representation of the numbers on the area, they do not indicate
correctly the population density, for many of the animals trapped on the
area ranged outside it in varying degrees, some perhaps merely over-
lapping its boundaries in the course of their wanderings. By plotting the
range of each individual rabbit, on the basis of distribution of its sites of
capture, attempt was made to determine what percentage of its range lay
outside the study area. Those having numerous records all well inside the
boundaries were assumed to forage entirely within the area. Those whose
records of capture clustered along one edge were assumed to range mainly
outside, the estimated percentage depending on the pattern of the location
records and the known extent of typical foraging ranges in other indi-
viduals. Those for which only a single record was available near an edge^
were assumed to range almost entirely outside the area. In a few instances
where only one or two location records were available, the estimate was
merely a guess but usually the range was roughly evident. In several
samplings by live-trapping of a peripheral strip, many of the marked
rabbits were recaptured and the extent and direction of their activities
outside the main study area were indicated. Attempt was made to estimate
to the nearest 10 percent the portion of each range falling within the
trapping area, but at best these estimates are merely approximations.

For 103 rabbits trapped on the area in 1939, the sum of percentages
of ranges on the area totaled 6,575 ; dividing by 100, there were the
equivalent of nearly 66 complete "rabbit ranges" within the 80-acre
area. This indicates a population density of one cottontail to 1.2 acres.
For the 47 trapped in 1940 percentages of ranges totaled 3,000, repre-
senting 30 ''rabbit ranges" or a population density of one per 2.6 acres.
Using the data in a different manner, it appears that of the 103 present in
1939, 55 had ranges centering inside the area, 35 centered outside, and
13 centered in the immediate vicinity of the boundary, or yielded such
meager data that it could not be determined on which side they centered.
In 1940 comparable handling of data indicated that 32 centered inside
and 15 outside the area.

It is evident that, in the vicinity of the trapping area at least, the
1939 summer population had undergone sharp reduction by the summer
of 1940, but with no apparent cause. In a preliminary paper on ecology
of wildlife species of the San Joaquin Experimental Range (Horn and
Fitch, 1942:115) it was stated concerning the cottontail population:
"***during 1939 and early 1940 their numbers remained fairly stable

COTTONTAIL POPULATION 167

except for seasonal fluctuations. During the summer of 1940 the numbers
dropped to less than half of the ]9:{f) summer p()[)ulations, most of this
reduction occurring over a six-weeks' period." Further study of the
data suggests anotlier interpretation. No dead or diseased rabbits were
seen during the time of the supposed reduction which was based mainly
on impression. But it does appear that the reduction must have involved
unusually heavy mortality of adults rather than mere variation in the
success of the annual crop of young. Thus of the 103 rabbits caught on
the area in 1939, only 9, or 8.7 percent were recaptured in 1940. But of
the 47 total caught there in 1940, 18, or 38 percent were recaptured in
the 1941 season. Survival expectancy of adults was more than four times
as high in the summer of 1940 — other things being equal. Possibly during
the critically dry conditions of 1939, the animals moved about so much
more extensively that this, rather than actual mortality, was an important
cause of population turnover on the 80 acres.

In the early summer of 1940 an attempt was made to determine the
population density of the rabbits over the range as a whole. Road counts
were made, driving in a car at 10 miles per hour after dark in the early
part of the night at times apparently favorable for rabbit activity. The
roads followed passed through 12 different experimental pastures total-
ing 1,754 acres in area. For each road count made on these various
pastures a comparable road count was made on the 80-acre study area
where the population was evident through live-trapping data. Thus the
relative abundance could be judged from the numbers seen per unit of
time on any area as compared with the trapping area.

On the 80-acre trapping area, in 739 minutes of driving, there were
seen 41 rabbits, or an average of one in 19.8 minutes. In 1,023 minutes of
driving on roads of the other pastures, 88 were recorded — an average
of one in 11.7 minutes. Thus rabbits were apparently 1.7 times as
abundant on the larger area. The population of the trapping area was
computed at one to 2.6 acres, or .384 per acre. Thus tlie population
density of the 1,754 acres would amount to 1.7 x .384, or .654 rabbits per
acre. This is the only available computation of the cottontail population
over the experimental range as a whole, but it represents a low point in
both the year-to-year fluctuations and the annual cycle. Thus, at times
it may amount to several per acre, especially in areas that are unusually
favorable as cottontail habitat.

The 80-acre studj' area appeared to be one of the less favorable places
on the Experimental Range for cottontails, as it bordered, and partlj-
included, rolling grassland where cover was relatively scant. On other
areas of the Experimental Range more rugged terrain with abundant
granite rock piles, patches of chaparral, and fallen live-oaks with their
dense protective screen of twigs, provided optimum cottontail habitat.

Feeding

The feeding of cottontails on the Experimental Range is determined
by the changing seasonal availability of food plants. In this region the
food consists almost entirely of annual grasses and broadleaf herbs. In
late fall, winter, and early spring (the growing season) many species
were suitable for food, providing succulence and high protein and
mineral content. In the summer dry season feeding conditions were much
less favorable ; protein and mineral content of the forage crop in general

168 CALIFORNIA FISH AND GAME

had dwindled, crude fiber had increased, and only a few species retained
succulence. This remaining succulence was concentrated in the larger
swales, and creek beds, but in years that are more than ordinarily dry
it may be largely lacking. Presence of water then becomes a critical
factor.

Seasonal trends in the feeding habits are best illustrated by extracts
from field notes concerning feeding behavior recorded on different dates.

In late March feeding rabbits were observed to take tips of grass
blades, foxtail fescue (Festucamegalura) and soft chess {Br omus mollis),
stems of popcorn flower (Plagiohothrys nothofulvus) , and fruits of filaree
(Er odium lotrys) . Throughout April the flowering heads of an abundant
small composite, gold fields {Baeria chrysostoma) were an important
food. Popcorn flower stems and soft chess heads and once a plant of ever-
lasting {Filago gallica) were also observed eaten in April. A rabbit eat-
ing heads of soft chess was seen to reject those of red brome (Bromus
rubens) after reaching up to sniff them.

In June dry heads of soft chess were an important food perhaps
because of ready availability. One rabbit watched for 58 minutes took 244
heads of soft chess and nothing else. Slender-leaf rush (Juncus oxymeris),
heads of foxtail fescue, plants of Spanish clover (Lotus americanus),
stalks of tarweed (Hemizonia virgata), leaves and seed heads of Aus-
tralian chess (Bromus arenarius), and heads of clover (Trifolium sp.)
were taken in quantity; oat (Avena har'bata) and leaves and bark of
buttonwillow (Cephalanthus occidentalis) were also seen eaten on one
or more occasions.

In July several observations indicated that stalks and heads of soft
chess continued to be the principal foods. Stalks and heads of fescue,
lupine (Lupinus formosus), tarweed, turkey mullein leaves (Eremocar-
pus setigerus), dock (Rumex sp.) and, on one occasion, dry oak leaves
were seen taken. The turkey mullein, dock, and tarweed were apparently
used because of their succulence at this season when most other vege-
tation was dry.

In August tarweed was increasingly used. In one rabbit followed
throughout a foraging period, tarweed was estimated to comprise 90
percent of the meal. In feeding on tarweed the animal usually cut the
stalk and ate outward from its base, discarding the terminal parts. Soft
chess heads and straws continued to be important foods. Several times
rabbits were observed grazing on the surface mat of cast seeds of foxtail
fescue. Eushes (Eleocharis and Juncus) already too closely cropped to
be accessible to stock, continued to provide an important source of food
and succulence to the rabbits. Spanish clover, turkey mullein, dock and
thistle (Cirsium sp.) also were recorded as being eaten in August.

In September rabbit grazing on east fescue seeds was recorded sev-
eral times ; also use of soft chess, toad rush, flowers of tarweed, and dry
navarettia (Ndvarettia sp.)

The only October feeding record obtained was of a cottontail taking
a dry turkey mullein plant.

The quantities of forage required to maintain a cottontail are not
well kno^vn. In a summer feeding experiment, a 340-gram young fed
for 25 days on dry wheat, with water available, ate on the average 14.5
grams daily — only 4.1 percent of its body weight. A 950-gram adult in
11 days of feeding ate an average of 23.7 grams daily — only 2.5 percent

COTTONTATTi POPULATION

169

of its body Avei*?lit. However, bol.li rabbits lost some weipht durinf? the
experiment, and this concentrated food is unrepresentative of tlieir diet
in the wiUl. Injj^Ies (1941:289) records tliat two adults which he fed a
mixture of {;reen forage for a 15-hour period ate 209 f^'rams and 171
grams, respectively. In estimating rabbit damage on the range, allowance
must be made for the fact that plants cut and destroyed are often only
partly eaten, that vegetation is advci-sely affected by trani[)ling, on the
runways and elsewhere, and that plants eaten back in the early stages
of growth are stunted. The total damage therefore greatly exceeds the
loss of vegetation actually consumed by the rabbits.

Weights

Weight was recorded at each capture, and was found to fluctuate
widely. Adults usually weighed between 750 and 1,300 grams; those in
good condition frequently weighed more than 1,000 grams. Day to day
fluctuations of 40 grams or more were often recorded, apparently due

WEIGHT

GRAMS

V — •

1000

800 _/

COO J

m m

200

•

J J

^40

0 N D

J J

^41

Figure 52. Weights of a female cottontail on dates of capture beginning soon
after leaving nest, showing rapid gain for first tbree months with more gradual and less
regular subsequent growth.

170 CALIFORNIA FISH AND GAME

mainly to differences in extent of feeding before capture. Individuals
caught frequently over periods of weeks often tended to lose weight,
possibly as a result of facial bruises sustained in their attempts to escape,
which perhaps made eating difficult and painful. Seasonal trends in
weights are somewhat obscured by this tendency to weight loss in con-
sistent repeaters.

In late summer of 1939 there was a general downward trend in
weights evidently resulting from the short forage crop with lack or
early disappearance of swale succulence during the dry season. No such
tendency at this time of year was apparent in 1940. Maximum weights
were recorded in April and May, but few were caught at that season,
as bait acceptance was poor.

For an adult female caught 21 times in nine different months over
an 18-month period, average monthly weights were as follows : August,
1939—1,052 grams; September, 1939,-1,012 grams; January, 1940—
1,055 grams; April, 1940—1,225 grams; July, 1940—1,180 grams;
August, 1940—1,110 grams; May, 1941—1,300 grams; August, 1941—
1,055 grams; February, 1942 — (dead in trap) — 825 grams.

Unusually complete weight records were obtained for one female
rabbit first trapped as a small juvenile soon after leaving its nest,
and recaptured frequently during the ensuing 17 months, even during
the winter season when bait acceptance was low. The weight records
for this individual are shown in figure 52.

Reproduction

Breeding is ordinarily limited to the late fall, winter, and spring
months — the growing season when green forage is abundant. In rabbits
trapped during the dry season, the genitalia had retrogressed so that
sex was not readily determined, and it was evident that breeding activity
had ceased. The reproductive physiology may be controlled by the
seasonal change in diet. As an exceptional instance, a one-third grown
young was seen in November, 1946, in the headquarters area. It must
have been born during the dry season, but the watered lawns and gardens
around the headquarters buildings may have provided green feed neces-
sary to stimulate reproduction at a season when it does not normally
occur. Orr (1940 :143) stated that "The breeding season of the Audubon
cottontail in California extends from December to June. " On the experi-
mental range observations suggest that it may begin and end somewhat
earlier. Concerning the rate of reproduction, Orr (loc. cit.) stated:
' ' Sufficient data are lacking to definitely state the number of litters born
annually, but considering the length of the breeding season it is not
improbable that in many instances this number may exceed two. The
average number of young per litter, based on records of 19 pregnant
females, is 3.6 with extremes of two and six."

On November 9, 1940, an adult female was seen gathering dry
grass for nesting material and carrying it to a burrow beneath an oak
bush. After pulling up each mouthful, she would deposit it in the freshly
dug burrow. Many mouthfuls of grass were gathered, all within three or
four feet of the bush. This was probably near the beginning of the breed-
ing season, and the nest evidently was being prepared for a litter of
young.

COTTONTAIL I'OI'III.ATION

171

On January 18, 1939, a nest was roiiiid on tlio, surface of the f,'roun(l
in a rounded depression, well concealed by a dense covering,' of hij^di
f?rass. This was in a swale of an ungrazed area. The one younj,' in the
nest weighed 60 grams.

On the following day a destroyed nest was found where it had been
dug out, in an exposed situation in sandy soil near a creek })ed. The nest
chamber was three inches beh)W the soil surface, and tlie cavity was about
eight inches long by five inches deep, with a bed of dry digger pine needles,
a softer interior of dry fescue and rush, and a lining of rabbit fur. A
fresh ground squirrel digging and feces were foiuid about a foot from
the nest suggesting the possibility that one of these rodents liad robbed it.

Figure 53. Immature Audubon cottontail

On January 25, 1939, a nest with two small young rabbits was dis-
covered. The nest cavity was just beneath the ground surface, and was
lined with rabbit fur but had no plant material. The entrance and the
cavity itself were so small that it would seem impossible for an adult
cottontail to enter. The young still had their eyes closed, and had a sparse
covering of hair.

On January 28, 1941, at about 10 a.m.. another adult was seen
making its nest. It was under a live-oak and was moving in a brisk, jerky
fashion examining the ground litter minutely, and from time to time
picking up dry oak leaves in its mouth. Having obtained a small mouth-
ful of leaves, with a few straws and other debris mixed in, it entered a
freshly dug hole with a mound of still moist earth in a more exposed
situation on the other side of the tree. After a few seconds it backed out

172 CALIFORNIA FISH AND GAME

having deposited its load, and resumed the search. In a period of about
five minutes it made 15 trips into the hole with nesting material — ^mostly
dry oak leaves and some dry grass (probably soft chess). At 4.30 p.m.
the site was located with difficulty and it was observed that the hole was
plugged with loose earth, and the burrow mound leveled and completely
covered with a layer of dry oak leaves. Four weeks later this hole was dug
out. The entrance was covered with dry oak leaves. The litter of young
presumably had been destroyed early by heavy rains. The nest cavity,
about a foot from the entrance, contained evidence of dead young
rabbits.

Ordinarily the nests are so well concealed that they are rarely found
while in use, but remains of those dug out and destroyed by predators
were found frequently during the winter and spring months. Usually
it was not possible to identify the predator involved. Only a few of those
seen destroyed were recorded. On March 21, 1939, three such destroyed
nests were recorded, and in the first week of May, 1938, several were
noticed.

On April 10, 1939, a small young cottontail was seen in tall grass
a few inches from the entrance of its nest burrow, into which it ran
when disturbed. The burrow was dug out and was found to have a tunnel
about eight inches long leading to a nest chamber five inches beneath
the ground surface, which seemed barely large enough to contain an
adult rabbit. It was lined with grass and a small amount of fur. Only the
one young was found in it.

The nest recorded latest in the season was one discovered on May 24,
1938, when attention was attracted to it by a rattlesnake which was
swallowing a very young rabbit and had three others already inside it.
An adult cottontail was about 15 feet distant, and remained in the
vicinity, allowing close approach. The nest was not dug out at the time
of discovery but was investigated later in the day. At this time a
second rattlesnake was found partly inside the nest, and it had eaten three
more young cottontails evidently of the same litter. The entrance to
the burrow was barely large enough to admit the snake 's body, but it was
partly plugged with loose dirt. The entrance led into a rounded chamber
about 7x4x4 inches, with a nest of dry grass (soft chess and foxtail
fescue) lined with rabbit fur.

From the foregoing accounts it is obvious that the habits of the
cottontail in this locality are variable, as regards site selected for birth
of litter, type of breeding burrow or lack of it, and composition of nest.
Ingles (1941 :24) has shown that the female cottontail may not even enter
the breeding burrow but returns to it infrequently to allow the young
to suckle as she stands over the entrance. In some of the nest burrows
discovered this arrangement seemed unlikely because the nest chamber
was several inches from the entrance. But other nests were so small that
it was difficult to see how the adult could have squeezed inside. It is
probable that squirrel burrows are sometimes used as breeding places
by the cottontail. Extensive squirrel burrow systems may have as many
as 100 open holes, many of which are not connected underground, and
only a few of the entrances are regularly used by the squirrels in going
to and from their nests. On winter mornings freshly dug mounds of
earth heavily tracked by cottontail were often found beside such burrows,

COTTONTAIL POPULATION 173

showing: that the rabbits liad enlarj,'cd iindcrj,'rounfl portions rluriii'jf
the ni<;ht.

Several times remains of cottontail too younj? to have left the nest
were found partly eaten on p:round squirrel burrow mounds, presumably
victims of tlie squirrels. On one occasion a squirrel was seen carryinj?
a live younc: cottontail in its moutli. Once a cottontail was seen cliasing
a squirrel around the edge of a bush, possibly in defense of its nest.

Natural Enemies

Several kinds of mammalian predators, at least four species of
raptorial birds, and two of the larg-er species of snakes, all numerous on
the experimental range and elsewhere in the general region, prey regu-
larly upon cottontail. Many records of predation were gathered, and an
attempt was made to compute the population density of each species
which might be important as a rabbit predator. These data are not
sufficiently complete to afford a clear picture of the role of predation
in limiting the cottontail population, especially since the reproductive
potential of the rabbits in this region is not well knoAvn. Some predator
species take only the small young before these have left the nest. Other
kinds take hea\y toll from the adult population, but it is evident that
the inexperienced young are especially susceptible to predation by many
natural enemies. The combined toll of the several predators' comprises
an impressive total, which must be a major factor if not the decisive
one in limiting cottontail distribution and abundance.

Coyote. Control of coyotes by trapping was begun on the experi-
mental range in the winter of 1935-36. The recorded numbers eliminated
each vear from the 4600-acre area were as follows : 1935-36, 35 ; 1936-37,
no record; 1937-38, "about 30"; 1938-39, "about 30"; 1939-40, 13;
1940-41, 13; 1942, 7; 1943, 5; 1944, 8; 1945, 1. Each year an unknown
number was also eliminated from adjoining ranches. It is evident that
in recent years the population has been held far below its former level.
In 1939 and 1940, at the time the rabbit population was studied, the
coyote population averaged perhaps one to 300 acres between the breeding
season and the time of control operations the following winter.

In a 3^ear-round collection of 1,173 coyote scats, mostly from regular
defecating places on roads and trails of the experimental range, in 1939
and 1940, 1,924 vertebrate prey items were identified. These made up
most of the food, though supplemented by a few occurrences of grasses,
berries, insects and some carrion. Of the 1924 items, "rabbit" (presum-
ably cottontail, but possibly pertaining to the relatively rare jack rabbit
in a few instances) made up 19.6 percent (21.1 percent in 1939, 17.0
percent in 3940). A truer interpretation of the relative importance of
rabbit in the coyotes' diet here may be gained by computing its per-
centage weight of the total. The total live-weight of recorded items was
estimated by obtaining the average weight for each species, multiplying
this by the number of its occurrences, then adding up these totals. Cotton-
tail, with an average of 800 grams, was the heaviest kind of prey recorded
taken by coyotes in this locality. The weight used as standard for the
cottontail, and those for other prey species represent in each case that
of a small adult. Many or perhaps most of the prey animals taken by
coyotes may have been immatures. The ratio of juveniles in various

174

CALIFORNIA FISH AND GAME

stages to adult animals was perhaps roughly similar for each, but the
usual adult weight affords the best standard of comparison.

Another variable is introduced by the inexact correspondence
between number of scat occurrences and number of individual prey
items eaten. But for squirrel- and rabbit-sized prey animals fairly close
correspondence might be expected (Murie, 1946: 275). For mouse-sized
rodents, and more minute items less accurate figures on the number eaten
could be obtained, but this inaccuracy would not affect the proportions
of the larger and more important items to any great extent. In general,
the assumption of one prey animal of the average weight of the species
for each scat occurrence, is thought to afford a rough approximation of
the percentage by weight of the coyote 's diet. The same assumption has
been made for the other carnivores and raptors discussed below. In Table
2 prey weights by percentage were obtained from computations on this
basis.

TABLE 2

Composition of Coyote Food
(Based on 1,173 scats)

Prey

Species

Average

weight

in grams

Occurrence in coyote food

Number

occtirrences

Computed

percentage

iy weight of total

recorded prey

Cottontail 800

Ground squirrel 500

Gopher snake 500

Woodrat 200

Pocket gopher 100

Kangaroo rat 60

Other (29 kinds) variable

Totals

377
414
79
162
234
361
297

1924

45.4
31.2
6.0
4.9
3.5
3.3
5.7

100.0

It is indicated that by weight cottontail made up a greater per-
centage of the diet than did any other kind of prey, and amounted to
nearly half of the total.

Gray Fox. At the time of the study, gray fox were probably
somewhat more abundant than coyotes on the area, judging from trap-
pers' estimates and the greater frequency with which they were seen.
However, no basis for estimating their actual numbers is available. In
June, 1938, a den was located with seven half-grown pups. Scattered
remnants of prey in the vicinity included parts of several cottontail.

A small collection of 87 fox scats made on the experimental range
contained 102 vertebrate prey items, besides a few insects, berries, and
other plant material, and one occurrence of carrion. The scats were
collected at different times of year but mainly represented the fall months.

The number of occurrences and computed percentages of the total
prey weight for the principal prey species of the gray fox are presented
in Table 3.

COTTONTAII. I'Ol'Ur.ATION

175

TABLE 3

Composition of Gray Fox Food
(Based on 87 scats)

Prey

Species

Occurrence in gray fox food

Average

weight

in grams

Number

occurrences

Computed

percentage

by weight of total

recorded prey

Cottontail 800

Ground squirrel 500

Woodrat 200

Bird (4 kinds) variable

Pocket soplier IIX)

Kangaroo rat 60

Other variable

Totals

11
12

17
10
14
17
21

35.7

24.4

13.8

10.2

5.7

4.1

6.1

102

100.0

Though this sample is too small to be relied upon, its trend seems to
indicate that rabbit was the most important single prey species of the
fox, and made up more than a third of the total.

Badger. Digging of badgers was frequently seen on the study
area, but no basis for estimating the population of badgers was discov-
ered. It is unlikely that these predators are able to catch adult cottontail
except under unusual circumstances, but they may be responsible for
much of the predation on small young in the nest. On many occasions
cottontail nests dug out and destroyed by mammalian predators were
found. Though the predator involved was never definitely identified, it
is probable that badgers figured in at least some instances.

A badger kept in captivity throughout one summer consumed daily
one small adult cottontail or its equivalent.

Bobcat. Judging from the occurence of their tracks, bobcats are
fairlj^ common in the more brushy and rocky parts of the Experimental
Range, but nothing was learned concerning their actual numbers, or the
food taken by them. As they are known to prev extensively upon rabbits
elsewhere, (Grinnell, Dixon, and Linsdale, 1937:615, 618, 620) it is
probable that they take large numbers of cottontail locally.

Red-tailed Hawk. This large raptor was determined to occur in
a permanent population of about one to 160 acres, with an additioiial
unstable population of fledged young and migratory adults, (Fitch,
Swenson and Tillotson, 1946). Many instances of predation on cottontail
were recorded. On one occasion the head of an ear-tagged adult male
rabbit from the study area was found beneath the perch of a hawk about
a quarter mile from where the rabbit had been trapped. On January 30,
1941, a hawk was seen to catch an adult cottontail by a sudden steep
swoop from its perch on a 15-foot oak snag. The rabbit must have emerged
from brush at the foot of the tree to cross an open space, completely
unaware of the danger. It took this hawk about two minutes to kill the
rabbit.

176

CALIFORNIA FISH AND GAME

Among 625 prey items of the hawks recorded as brought to the
3'oimg in the nests, cottontail were third in abundance with 62 records
(all of young ones), and on the basis of weight were computed to com-
prise 26.5 percent of the total. Among 4,036 prey occurrences from 2,094
red-tailed hawk pellets, the more important kinds both in numbers and
percentages of total weight are presented in Table 4.

TABLE 4

Composition of Red-tailed Hawk Food
(Based on 2,094 peUets)

Prey

Species

Average

weight
in grams

Occurrence in red-tailed hawk food

Numher Computed percentage
of iy tceighf of total

occurrences recorded prey

Ground squirrel 500 1,049

Cottontail 800 322

Gopher snake 500 190

Pocket gopher 10 794

Rattlesnake 300 70

Other variable 1,611

Totals 4,036

49.5
24.2
8.9
7.4
2.1
7.9

100.0

Cottontail was third in abundance among all prey taken by the hawks,
and comprised about one-fourth of the total prey weight taken.

Cooper Hawk. A few pair of these hawks nest on the experi-
mental range, and in winter the population is considerably increased by
migrants, but no definite figures on their numbers were obtained. In 1939,
two nests were observed, and a total of 41 prey items were recorded, two
of which were young cottontail (Fitch, Glading, and House, 1946 : 153).
The other prey items were all of smaller kinds, mainly birds and lizards,
and the cottontail were estimated to comprise approximately 16 percent
by weight of the recorded food.

In one instance an adult cottontail found freshly killed and partly
eaten under the edge of a bush was thought to have been the victim of
a Cooper hawk. These hawks are considered of secondary importance as
cottontail predators because of their relatively low numbers, small size
and preference for other kinds of prey.

Horned Owl. These large and common owls feed much more
extensively on rabbits than on any other kind of food. Seven times, in the
fall of 1938, spring and fall of 1939, and 1940, and late winter of 1941
and 1947, counts were made of horned owls heard at different points on
a 1,920-acre section of the range. These counts representing the minimum
number of owls present, varied from 15 to 25. Roughly, a population of
one owl to a hundred acres is indicated. A sample of 654 pellets represent-
ing approximately 1,471 individual prey items was analyzed in 1939^
1940 and 1946. For the principal prey species, number of occurrences
and computed percentages of total weights were as presented in Table 5.

COTTONTAIL POPULATION 177

TABLE 5

Composition of Horned Owl Food
(IJasfd on iJ'A polltfta)

Prey Occurrence in horned owl food

Axierage Numher Computed pcrrmtage

treight of by tceiyht of totnl

Species in grams occurrences recorded prey

Cottontail 800 20r) 61.1

Woodrat 200 240 17.9

Kangaroo rat GO 201 4.r>

Pocket gopher 100 115 4.3

Ground squirrel 500 13 2.4

Reptile (at least 8 kinds) variable 44 5.0

Bird (at least 12 kinds) variable 45 2.3

Other (including many insects) variable 608 2.5

Totals 1,471 100.0

It is indicated that cottontail made up more than half the food by
weight, though taken in slightly smaller numbers than woodrats.

Barn Owl. These are much less common than horned owls on the
Range, and were seen at only a few places. In a collection of 240 pellets
there were 517 prej^ items of which 415 were pocket gopher and pocket
mouse. Only four were cottontail (all young) which were computed to
make up around 3 percent of the total prey weight represented by the
sample.

Rattlesnake. This reptile is probably the most common of all
rodent and rabbit predators on the Range. Over a three-year period 679
were marked and released, and the ratio of these recaptured to others
seemed to indicate a population of two or three per acre, but accurate
census is impracticable as the figures might be distorted by many
unknown variables. Of the rattlesnakes recorded, nearlj^ half were adults.
A total of 271 prey items were identified from stomachs and droppings of
the snakes. For the principal prey species, number of occurrences and
computed percentages of total weights see Table 6.

TABLE 6

Composition of Rattlesnake Food
(Based on 271 food items)

Average

tveight Numier of Percentage of

Kind of prey in grams occurrences total prey weight

Ground squirrel 206 111 70.5

Cottontail 206 24 15.2

Kangaroo rat 60 32 5.9

Gopher 67 12 2.5

Other variable 92 5.9

Totals 271 100.0

178 CALIFORNIA FISH AND GAME

Though this food sample is small, as compared with those obtained for
carnivores and raptors, prey weights were determined with a precision
not practicable for the predatory mammals and birds. Food items were
palped from snake stomachs, and were actually weighed, except those in
which digestion had reached an advanced stage.

From these figures it appears that cottontail make up nearly one-
sixth of the snakes' food. As a result of the winter and early spring
breeding season most of the young were already too large for the snakes
to eat when the latter emerged from hibernation. The peak of rattlesnake
activity occurs during April, May and early June and all the records of
predation of rabbits occurred during that time, involving late litters of
young rabbits in the nest and large adult snakes in every instance.
Squirrels and kangaroo rats were often found dead, showing evidence
of rattlesnake bite, but some of the snakes involved were known to haye
been too small to eat the animals they had killed. Some rabbit mortality
may occur also. On June 28th, an adult rattlesnake was seen to strike a
cottontail in the field. Rabbits are probably less liable to be killed in this
way than are burrowing rodents which often encounter the snakes under-
ground.

Gopher Snake. This species is much less common than the rattle-
snake locally — perhaps only one-fourth as numerous. A total of 70 food
items were palped from gopher snake stomachs ; and an analysis of these

is presented in table 7.

TABLE 7

Composition of Gopher Snake Food
(Based on 70 food items)

Average

weight j^ umber of rerccnfnge of

Kind of prey in grams occurrences total prey weight

Cottontail 400 3 37.1

Ground squirrel ISO 5 27.9

Woodrat 200 3 18.6

Bird egg 8.5 20 5.3

Gopher 130 2 4.0

Other variable 37 7.1

Totals 70 100.0

The high percentage of cottontail in this small sample may be unrep-
resentative. One giant gopher snake, nearly seven feet long, had eaten an
adult cottontail which weighed as much as most of the smaller food items
combined. Such incidents as this must be rare, and comparatively few
gopher snakes are big enough to swallow any but nestling cottontail.

Discussion. The data set forth above suggest that the cottontail
bears the brunt of predation pressure from most of the larger species of
mammal, bird, and snake predators. The breeding season is long, and adult
females may soon replace lost litters, or may normally rear two or more
litters in a year, thus offsetting the heavy losses to natural enemies.

The summer population of adults and well-grown young after the
breeding season amounting in 1939 to one per 1.2 acres, represents a
rabbit-weight of about 670 grams per acre, a figure to be borne in mind
in connection with measured predation factors.

COTTONTAIL POPULATION 179

Compntntion of the ral)bit-\v('i^lit per acre eliiniiiatc.l hy predation
has been attempted on the basis of the known or estimated population of
each predator species, the normal daily food requirement, and the per-
centage of the food weight which rabbits comprise. The popiiji'i^inn nf
coYotL^s was comoutcdjit one to more than :'"<| nci-u.< ; t j i c .fny [i(>[tuliitifiii»
at possibly the same fi"y^ure_(or probably somewhat moinO. the rcd-tailcjl

laj^'lt at one to ibU acres: h^^rn^*;^ W'^ ^* ""^^ ^" "I^Q fteres- ratthisuakc 2^
per acre ; gopher snake'.G per acre, lleducintr tliese fiL''nres to popubutum

tensity, per acre ancT multipb^m^ by the food rcniiiremcnt. and the per-
centage comprised b}'- ra|)bit. we^ obtain the data presented in Tal)le P, .

TABLE 8
Cottontail Weights Consumed by Predators

l2 coo C « rt^

•03 TS'S rio tto -ao ^ -> so-a —

I S§ -| 5- ^« oS ^3-

1 Drag vs^ i " o_? ^ssr

I 32 I " I S^ ■= = §

1 i i^ it- il"

i ! ! I I g: I--

'I I I -i

' i ' 11"

I 1 I I I I 1

Coyote .0033 x GOO = 1.98 x 365 = 722 x 45.4 = 328.0

Rattlesnalve 2.5 x 2 = 5.00 x 365 = 1825 x 15.2 = 277.4

Horned owl .010 x 120 = 1.20 x 365 = 437 x 61.1 = 267.0

Gopher snalce .6 x 2 = 1.2 x 365 = 438 x 37.1 = 162.5

Fox .0033 X 300 = .99 x 365 = 361 x 35.6 = 12!).0

Red-tailed hawk .0062 x 120 = .74 x 365 = 270 x 24.2 = 05.0

Total 1228.9 grams

This summation does not include the rabbits eliminated by bobcats
and badgers, but both are among the more important cottontail predators.

Thus it appears that predation annually might eliminate a rabbit-
weight of about double the nonbreeding population of adults and well
gro"\vn young present in summer. Admittedly, at each stage of the com-
putation a substantial margin of error is probable so that the figures
obtained cannot be considered more than a rough indication of the magni-
tude of losses to each kind of predator. If, in the food composition of a
predator, the proportion of young were higher among cottontail than
among other kinds of prey, the percentage of cottontail computed would
be too high. However, it is probable that the proportion of young among
the ground squirrel, woodrat, and gopher snake, in prey samples was
fully as large as among cottontail. Each of these species has, like the
cottontail, a high reproductive potential and a rapid population turn-
over with even greater differentials between young and adult weights.
and they were the only ones other than cottontail comprising substantial
percentages of the diet in any of the predators. The populations of
predator species are variable according to time and place, and all of them
are computed on a somewhat doubtful basis for application to the experi-
mental range as a whole ; for the red-tailed hawk and horned owl, how-
ever, the figures used represent the absolute minimum. For rattlesnakes,
gopher snakes, coyotes, and especially foxes, the population figures are
less definite. The average daily individual food consumption under
natural conditions is somewhat speculative. This is especially so in the

180 CALIFORNIA FISH AND GAME

case of the snakes, and the figure used is based on the average individual
weight, assuming that each snake consumes twice its body weight during
the growing season as suggested by data obtained from several kept in
confinement. For the rattlesnake most feeding records were obtained in
April and May when small cottontail are available — but from June
"through October rabbits are not breeding and their young have grown
too large to be swallowed. Few feeding records were obtained for
snakes during this latter two-thirds of their active season, as they are
then secretive or nocturnal. But it may be surmised that kangaroo rats
and gophers are then substituted for the young rabbits and squirrels
taken in spring.

For the horned owl there is a probability that the numbers of cotton-
tail assumed to have been eaten was too high, for, unlike the other prey
species, the cottontail is large enough to furnish several owl meals. Thus
one might be counted several times from its limb bones and vertebrae
appearing in several pellets, whereas the other prey species were generally
identified from skulls revealing accurately the actual numbers eaten.

The predation calculated is not necessarily too high; it seems
entirely possible that the rabbits are adapted to withstand such pressure
by virtue of high reproductive potential. Ingles (1941 : 243-6) records an
instance of a female marked soon after birth, which had matured and
produced a litter of its own at the age of six months. Many of the
young born early in the breeding season, in fall, may mature in time
to produce litters before the breeding season is ended by the drought con-
ditions of the summer. Females that are mature in the fall at the beginning
of the breeding season might be expected to produce nine young apiece
during the seven or eight months of green growth if the average of 3.6
young per litter and two or three litters annually mentioned by Orr
(loc. cit.) is representative. Females which lose their litters early might
produce an even greater number. The young at birth probably weigh
around 30 grams, and upon leaving the nest from 11 to 14 days later, they
have increased to several times this weight. Growth during subsequent
weeks is extremely rapid (Fig. 52),

In recent years eeologists have tended to minimize the importance
of predation factors in controlling vertebrate populations. Errington
(1946) has summed up the literature of predation, and presents a fairly
convincing case to show that " intraspecific self -limiting mechanisms
basically determine the population levels maintained by the prey.'"
('* * * ^]^g patterns revealed may look remarkably little influenced
by variations in kinds and numbers of predators. ' '

Concerning rabbits, Errington (op. cit. 154-155) states that though
more tolerant of crowding without intraspecific strife, "they are by no
means free from automatic mechanisms [determining their upper and
lower population limits in a given habitat.] * * * again and
again lagomorphs recovering from depressed levels show rapid popula-
tion gains from one year to the next, the attentions of wild flesheaters
notwithstanding. ' '

The matter is not merely one of lagomorphs being prolific or of
making their gains when enemies are either numerically or proportionally
scarce, as there are too many instances of lagomorph populations appar-
ently conforming to patterns, even despite pronounced differences in
numbers of such able hunters as horned owls and foxes. ' '

COTTONTAIL POPULATION 181

On the San Joaquin Ranj^e there is no direct evidence that predation
actually holds the cottontail population to any given level. The situa-
tion is complex, however, because several common predators take larj^e
numbers of cottontail without being entirely dependent on tliom ; all
could probably adjust themselves to absence of cottontail by taking
larger numbers of the abundant ground squirrels, woodrats, and other
rodents. The predators also prey to some extent upon each other, at
least hawks, owls, coyotes and foxes all prey upon both rattlesnake and
gopher snake. Individual predators are long-lived as compared with
their rabbit or rodent prey, and survive fluctuations in the populations
of the latter. Even on areas of a few acres, the cottontail, or rodents, are
not uniformly abundant but are concentrated where conditions of food
and cover favor them ; they are sensitive to changing weather conditions
which result in expansion or contraction of their preferred ecologic
niches, and their numbers change in response. Each species is, however,
favored by a different set of conditions, so that increase in one kind
is apt to be accompanied by a more or less compensatory decrease in
another. The kangaroo rat, for instance, is favored by arid conditions
with sparse vegetation and its peak in numbers on the Experimental
Range followed a series of dry years. The ground squirrel is also favored
by a sparse forage crop, whereas the cottontail prefers a habitat with
thickets providing surface cover. Response to such conditions can be
seen in the varying abundance of rabbits and rodents on different parts
of the Range; on the ungrazed headquarters area, having chaparral
thickets and rank growth of swale vegetation, cottontails are more numer-
ous than elsewhere, squirrels and kangaroo rats less so.

While changes in abundance of both cottontails and predators are
known to have occurred since 1935, records are too fragmentary to show
either clear cut correlation or lack of it. Coyotes were first controlled
in the winter of 1935-36, and 35 were trapped during a few weeks period.
Nearly as many were caught in each of several succeeding years, but by
1939 the population was much reduced. In August, 1936, at the time they
were still numerous, Kenneth A. Wagnon recorded in his field notes
that cottontail were extremely abundant around the Experimental Range
headquarters, where as many as 50 congregated on the lawns in the
evening, and he speculated that this high rabbit population might be
the attraction for the coyotes. The reduction of coyotes to a fraction of
their former numbers did not result in any noticeable increase in rabbits.
The hawk and owl populations have been stable, but rattlesnakes over
the Experimental Range as a whole, have doubtless been somewhat
reduced by the continual drain on their population imposed by human
activity.

Intraspecific, self-limiting mechanisms in the cottontail population
of the Experimental Range were not evident, either. It is doubtful
whether any mortality results from intraspecific strife — no fighting or
other evidence of intolerance was observed even when many rabbits were
concentrated on a small area. Their food supply is subject to even heavier
use by other herbivores, particularly domestic stock, so that the amount
remaining at the end of the dry season is not determined primarily by
th? number of cottontail. Conditions of critical severity with respect to

182 ■ CALIFORNIA FISH AND GAME

availability of moisture may occur late in the dry season, for at this time
cottontail congregate at water, and avidly seek any remaining succulent
vegetation. Eabbits in situations where no water is available may com-
pete severely with each other for preferred foods such as rushes, already
so closely cropped as to be unavailable to grazing stock. For young in the
nest, weather conditions may be critical and heavy rains may result in
their death by chilling or even drowning.

So far as observed, however, actual mortality in nearly all instances
involved predation, upon individuals which were not obviously handi-
capped or diseased and which were well provided with food and shelter.
That is, they were not part of a surplus population crowded out into a
precarious marginal existence in critical periods, as in cases cited by
Errington (op. cit.). ,:,

"Vunerability" of the cottontail population may depend n!pt so
much on the conditions of food and shelter available to the rabbits as on
the numbers of predators present and the relative availability to them
of ground squirrels, woodrats, pocket gophers and kangaroo rats. At
least it seems fairly certain that the medium to high populations of
these several rodents make possible the existence of the predators which
account for most of the rabbit mortality.

Disease. Evidence of disease was rarely noticed among the rab-
bits trapped, though nearly all of them were heavily infested with large
fleas. On one occasion a cottontail died suddenly for no apparent reason
when it was being removed from a trap, suggesting the possible exist-
ence of shock disease in the population, but no autopsies or laboratory
tests were carried out to verify this hypothesis.

On February 7, 1941, a cottontail evidencing sluggish behavior was
noticed, and it allowed an observer to approach within eight feet, then
crawled into a rock crevice. It made no effort to escape when picked up
and died two hours later. There was a swelling about the size of a walnut
on the lower jaw, containing a yellowish white mass of cheesy consistency,
and a slightly smaller inguinal swelling. The liver was somewhat dark-
ened with well-separated yellowish spots on its surface. This rabbit had
an unusually heavy infestation of fleas ; it was estimated that there were
at least 100 on its head alone. Other rabbits seen at this location on the
same day and during subsequent weeks appeared to be normally healthy.

Herman and Jankiewicz (1943) examined 43 cottontails from the
experimental range, and found coccidia infections prevalent ; six different
types were described. The infections did not appear to be acute and their
effect on the rabbits is not known. Cottontail experimentally infected
with Eimeria stiedae, a coccidial liver pathogen of domestic rabbits did
not develop severe infections, as do domestic rabbits, suggesting partial
immunity. The only ectoparasite recorded by these authors was a flea
(Ctenocephaloides felis). The animals were shipped to these authors in
Los Angeles and the ectoparasites were probably lost during handling
prior to shipment. Internal parasites found by them included two intes-
tinal protozoans (Trichomonas, Chilomastix), two nematodes (Ohelis-
coides cuniculi and Nematodirus leporis), and several cestodes (Taenia
pisiformis, Cittotaenia variahilis and other species of the same genus
and Raillietaenia retractilis).

COTTONTAir, I'OIMI.A'riDX 183

Summary

The cottontail is abundant in open woodlands of the Sierra Nevada
foothill belt in central California. At the San Joafiuin Exporimontal
Kanjiv it compotes heavily with livestock in use of the vegetation. Dnrinf?
the suumicr dry season, the rabbits look <i:rain baits freely, but durin»^
the jirowinj>- season they preferred succulent natural foods.

Knowledge of the chanpinfr seasonal bait acceptance is of practical
value in connection with ninnafrement operations. At timos, locally, it
may be desirable to remove, by poisoninjj-, cotloutail populations which
are known to be diseased, or which are causing obvious damap^e to culti-
vated crops or range forage. More often it may be desirable to retain
the cottontail population while removing certain harmful rodent species.
Ground squirrels, for instance, are controlled by annual poisoning on
many of the foothill ranges. Squirrel poisoning operations during the
winter or spring months would result in relatively light losses to the
cottontail population since grain bait is not especially attractive to the
rabbits at that season ; but summer or early fall squirrel poisoning might
at the same time reduce the rabbit population even more drastically.

Live trapping and marking of rabbits through a three-year period
resulted in 1,159 captures of 228 individuals, and indicated that these
animals are attached to definite small areas. Diameters of "foraging
areas" within which individual rabbits usually stayed were roughly
perhaps 700 feet, but were variable and occasionally long foraging trips
were made. Immature animals appear to range less widely than adults.
Of 23 rabbits released at a distance from the point of capture, three
made homing movements of 4,400, 3,550 and 3,150 feet respectively; 10
were recaptured near the place of release, and the others were not again
recorded.

One rabbit was recorded to have shifted its range a distance of 3,300
feet. Such movements may be fairly common and important in the
population turnover of small areas. Water and succulence in the dry
season attract unusual concentrations of cottontails.

In censusing the population by the ratio of marked ones to others
during the dry season of each year on the 80-aere study area, the following
numbers were recorded : 1939, 153 ; 1940, 53 ; 1941, 95. Allowing for
movements outside the 80 acres, the population density was calculated
as one per 1.2 acres in 1939 and one per 2.6 acres in 1940. In its cottontail
population, the 80-acre study area was below the average of the experi-
mental range as a whole. Road counts over 1,754 acres of the experimental
range compared with similar counts on the trapping area, indicated a
population density for these pastures 1.7 times that of the study area.

Observations on the feeding habits indicated that in spring the
common forage plants most used by cattle, soft chess, foxtail fescue,
broadleaf filaree, popcorn flower, and gold fields, make up the bulk of
the cottontail diet. Through the summer heavy use of soft chess continues,
but as the forage crop in general dries out, there is a distinct tendency
to concentrate on swale vegetation where succulence remains. Clovers,
rush, and dock are swale plants especially sought at this time. Leaves,
seeds, and stems of tarweed, and leaves and stems of turkey mullein are
often taken in summer. These along with dock, constitute plants rather
unpalatable to livestock, so that competition is somewhat reduced during

184 CALIFORNIA FISH AND GAME

the dry season. Cast seeds of foxtail fescue constitute an important food
source during the dry season.

Numerous wildlife species predatory on cottontails occur in the
region of the experimental range. In order of their importance, predators
included the coyote, rattlesnake, horned owl, gopher snake, gray fox, and
red -tailed hawk. From the proportion of rabbit found for each species
in the course of numerous scat, pellet, and stomach examinations, the
population density of these predators, and the individual food require-
ment of each kind, it was estimated that predation factors annually
might consume a cottontail weight of 1,229 grams per acre. This greatly
exceeds the weight of the cottontail population actually present in late
summer, before the breeding season begins. Nevertheless, the cottontail
may be able to withstand this severe predation pressure by virtue of its
long breeding season with possibly several litters of young annually for
each adult female.

One diseased and dying rabbit was found, but no evidence was
obtained that disease causes extensive mortality or affects population
trends in this locality.

References

Errington, Paul L., Francis M. Hamerstrom and Francis M. Hamerstrom, Jr.

1940. The great horned owl and its prey in north-central United States. Agric.
Esper. Sta., Iowa State Coll. of Agric. and Mech. Arts Research Bull.
277 : 758-850.

Errington, Paul L.

1946. Predation and vertebrate populations. Quart. Rev. Biol. 21 : 144-177 and
221-245.

Fitch, Henry S., Ben Glading and Verl House

1946. Observations on Cooper hawk nesting and predation. Calif. Fish and Game,
32 : 144-154.

Fitch, Henry S., Freeman Swenson and Daniel F. Tillotson

1946. Behavior and food habits of the red-tailed hawk. Condor 48 : 205-237.

Fitch, Henry S. and Howard Twining

1946. Feeding habits of the Pacific rattlesnake. Copeia 1946 : 64-71.

Grinnell, Joseph, Joseph S. Dixon and Jean M. Linsdale

1937. Fur-bearing mammals of California. Vol. 2 Univ. Calif. Press, pp. xiv and
377-777, pis. viii-xiii and figs, in text 139-345.

Herman, Carlton M. and Harry A. Jankiewicz

1943. Parasites of cottontail rabbits on the San Joaquin Experimental Range.
Journ. Wildlife Management 7 : 395-400.

Horn, Everett E. and Henry S. Fitch

1942. Interrelationships of rodents and other wildlife of the range. Univ. Calif.
Agr. Exp. Sta. Bull. 663 : 96-129.

Ingles, Lloyd

1941. Natural history observations on the Audubon cottontail. Journ. Mam-
malogy 22 : 227-250.

Murie, Olaus J.

1946. Evaluating duplications in analysis of coyote scats. Journ. Wildlife Man-
agement 10 : 275-276.

Orr, Robert T.

1940. The rabbits of California. Occas. Papers of Calif. Acad. Sci., No. 19 : 1-227.

Talbot, M. W., and Harold H. Biswell

1942. The forage crop and its management. Univ. Calif. Agric. Bull. 663 : 13-49.

DISTINCTIVE CHARACTERS OF THE SPECIES

OF ANADROMOUS TROUT AND SALMON

FOUND IN CALIFORNIA '

By Lro SirAPOVAi.ov

Bureau of Fish Conservation

California Division of Fish and Game

Common and Scientific Names

Five species of salmon and two species of anadromous trout have
been taken in California.^ Our official common names for them and their
scientific names are given in the following list :

Steelhead Rainbow Trout Salmo gairdnerii

Cutthroat Trout Salmo clarkii

King Salmon Oncorhynchus ishawytscha

Silver Salmon Oncorhynchus kisntch

Pink Salmon Oncorhynchus gorbuscha

Chum Salmon Oncorhynchus keta

Red Salmon Oncorhynchus nerka

Some persons will recognize these fishes under other names. Other
common names that have been used for the King Salmon are black salmon
(applied to individuals that have become dark because of long presence
in fresh water), chub salmon (applied to young males), dog salmon or
hookbill (applied to males with hooked snouts), silver salmon (applied
to young fish fresh from the ocean in the Sacramento River system),
Chinook salmon, spring salmon, quinnat salmon, and tyee salmon. Other
common names applied to the Silver Salmon include jack salmon (applied
especially to young males), dog salmon or hookbill (applied to males
Avith hooked snouts and red sides), coho, and silversides. Other common
names which are sometimes used for Steelhead Rainbow Trout include
rainbow (applied to individuals that color up in fresh water without
going to sea), half-pounder (applied to small sea-run individuals or
large, silvery individuals that have remained in fresh or brackish water,
Aveighing usually from one pound to two and one-half pounds, especially
in the Eel River system), summer salmon (applied to sexually immature
spring-run fish, especially in the Middle Pork of Eel River) , salmon trout,
steelhead, and steelhead trout. Pink Salmon are also known as humpback
salmon. Chum Salmon as dog salmon, and R^d Salmon as sockej^e salmon
or blueback salmon. The non-anadromous form of the latter, recently
introduced into California, is known as the Kokanee, but elsewhere has
also gone under the names little redfish and silver trout.

Distribution

The Steelhead Rainbow Trout is the most widely distributed of our
anadromous salmonids, spawning in practically every coastal stream,

1 Submitted for publication, April, 1947.

2 Anadromous fishes are those which spend a portion of their lives in the ocean and
then ascend streams to spawn.

(185)

186

CALIFORNIA FISH AND GAME

small or large, that has not been rendered unfit by man, from the Oregon
line to the Mexican border. The sea-going Cutthroat Trout is confined to
the northermost portion of the State, to streams in Humboldt and Del
Norte counties.

The King Salmon spawns extensively in the Sacramento-San Joaquin
river system, although now blocked from the majority of its natural
spawning grounds by dams, and in the larger streams to the north. The
spawning range of the Silver Salmon in California is from some of the
streams tributary to Monterey Bay to the Oregon line. Like the steelhead,
it enters both large and small streams, but appears to be absent from the
Sacramento-San Joaquin river system. The Pink Salmon spawns in some
of the streams in j\Iendocino County, but these runs are irregular, and
in the State as a whole the species is of minor importance both for angling
and commercially. The other two species, the Chum Salmon and the Red
Salmon, are only occasional visitors to our waters.

Living things are prone to provide us with exceptions, and so it is
with trout and salmon. Individuals or small spawning runs of the various
species have on occasion entered scattered streams outside their normal
range. For example. King Salmon have been recorded from as far south
as the Ventura River, in southern California,

The ocean range of at least the King Salmon extends to the south of
its normal spawning range. The commercial catch in Monterey Bay has
totaled millions of pounds annually, although spa-^ming does not occur
normally south of the Golden Gate.

Eecognition of Specimens in Hand

Belonging to the same family of fishes, the Salmonidae, all of the
species in general resemble each other, but possess certain characters by
which they may be distinguished (Fig. 54) .

Snout

Dorsal fin

lateral line
nostril 1

Adipose fin
Caudel

Branchiostegal fays

Right pectoral fin
Left pectoral fin

Right ventral fin

■Anal fin I
Caudal (tail) fin
Left ventral fin

Figure 54. Diagram showing some of the external structures which are used in identi-
fying salmon and trout

TROUT AND SAIjMON IN CALIFORNIA

187

If the fish are in liatul, t.iie most usel'iil characters for distiii^'uishiti;,'
sea-run trout from salmon for the layman and the an^'ler unfamiliar with
fish anatomy are the deep caudal peduncle and whitish mouth parts of the
former, in contrast to the relatively slender caud.-il jx-duncle (Ki<,'. 55)
and blackish mouth parts of the salmoli. It is dinicuit to pick up a steel-
head or cutthroat by grasping the tail, but a salmon may be readily held
in this manner. In addition, the caudal (tail) fin tends to be squarish in
the fronts, while in the salmons it lias an inward curve. Finally, the dorsal
fin of adult salmon, except King Salmon, is plain or witli dark bh)tciies,
but without definite spots, while the trouts possess definite blackish spots
on the dorsals.

Steelhead Rainbow Trout
King Salmon

Figure 55. Outlines of the posterior portions of a steelhead and a salmon each of
the same length, showing characteristic differences in depth of caudal peduncle and shape
of caudal fin.

Figure 56. Diagram illus-
trating method used in count-
ing dorsal and anal fin rays.
The last ray is often branched
at base and is counted as one.

Although the above general rules are
useful, it is best to rely on the characters
which remain unchanged throughout life,
such as numbers of rays in different fins,
oblique rows of scales crossing the lateral
line (one such oblique row is sho^^Ti in Fig.
54 but not labeled), pyloric caeca (the small,
fingerlike appendages of the stomach), giU
rakers, and branchiostegal rays, for definite
recognition when the fish are in hand (See

188 CALIFORNIA FISH AND GAME

Figs. 54, 56, and 57). These characters are
Sill ftroh^^^^^^^ used in the following key, which is based on

alternate characters. One character is given

under la and the contrasting character

, . , under lb, and so on through 2a and 2b and

flimments. Subsequent numbers. If your fish fits under

Figure 57. Diagram of 1^, proceed to 2a and 2b and choose between

gill arch, showing gill rak- them. But if it fits Under lb, proceed to 3a

ers. The count includes the I ^

upper and lower halves of and 3b and choosc between them, and so on

the arch. Always count all ,•■, -, i j n i

rudiments. Until you have placed your fish.

KEY TO THE SPECIES OF ANADROMOUS TROUT
AND SALMON FOUND IN CALIFORNIA

la. Rays in anal fin not more than 12. Trouts.

2a. Red dash in cleft under each side of lower jaw.

Cutthroat Trout, Salmo clarkii.

2b. No red dash in cleft under each side of lower jaw.

Steelhead Rainbow Trout, Salmo gairdnerii.

lb. Rays in anal fin more than 12. Salmons.
3a. Gill rakers 30 or more on first arch.

Red Salmon, Oncorhynchus nerka.

3b. Gill rakers fewer than 30 on first arch.

4a. More than 170 oblique rows of scales crossing the lateral line.

Pink Salmon, Oncorhynchus goriuscha.

4b. Fewer than 170 oblique rows of scales crossing the lateral line.
5a. Pyloric caeca fewer than 100.

Silver Salmon, Oncorhynchus kisutch.

5b. Pyloric caeca more than 100.
6a. Rays in anal fin 13 or 14.

Chum Salmon, Oncorhynchus keta.

6b. Rays in anal fin 15 or more.

King Salmon, Oncorhynchus tshaivytscha.

Recognition in the Water

Recognition in the water is more difficult, but must be used, for
example, at counting stations. Here, general body form and coloration
and configuration of different parts of the body must be relied upon.
These characters vary not only with the species, but also with the sex,
size, degree of sexual maturity, and length of stay in fresh water of the
individual fish, so that experience is necessary to use them. The fish
counter should check his identifications of fish in the water by dipping
up individuals until he is sure that he is distinguishing his fish correctly.
Since many California streams contain steelhead. King Salmon, and
Silver Salmon, but only a few of any of the other species, the following
discussion of field characters will place emphasis on the above-named
three. The statements made are based on experience in California, but are
set down advisedly, and all field workers are requested to inform the
writer regarding those which are of little use or do not hold good under
all conditions and in all localities, and also of any useful characters
which have been omitted.

TROUT AND RAI>MON IN CALIFORNIA 189

In general body form the trouts are .sliianier than the salmons. In
the salmon males the snout tends 1o become much more hooked, elonf,'ated,
and deformed at spiiwnini; time than it does in the males of the trouts.
Some Kinf? Salmon reaeli a lar^'er size than is attained by any of the
other salmoinds, and may be distinguished on this basis alone. The
pectoral fins of the Silver Salmon are relatively longer than those of
the steelhead. The Silver Salmon usually has a more conical head than
do either steelhead or King Salmon. It may also be distinguished from
the other two, particularly the steelhead, by its white nostrils. As the
season progresses, however, the nostrils of the King Salmon also tend
to appear Avhitish.

At sea all species of salmon and trout take on a general silvery
coloration, but after they enter fresh water and ripen sexually, they
assume colors which are characteristic. The King Salmon of both sexes
tend to become blackish, with dark coloration on the sides of the head.
Little red color is shown by this species except in the large males, and
even in these it never approaches the brilliancy that it does in Silver
Salmon. The silver males often become quite red — usually a brick red —
while the females become dull bronzy. In the steelhead the sides remain
more or less silvery, but develop a broad flesh-colored or rosy lateral
band or wash, brightest on the gill covers.

In the Pink Salmon, the spawning males become quite red, more or
less blotched with brownish. The fleshy dorsal hump becomes much
developed and the jaws exceptionally elongated and hooked. The females
are olive-green on the sides, with dusky stripes. The breeding males of
the Chum Salmon also become much distorted, with coloration generally
blackish above, sides brick red, often barred or mottled, and fins blackish.
In the Red Salmon, the spawning males possess brilliant red backs and
sides, with the reddish color extending to most of the fins, under parts
that are dirty white, and heads olivaceous above and on the sides. The
mature females are dark red, with green and yellow blotches. The sea-run
cutthroats are extremely variable in coloration and form. Generally, the
color is olive green on the sides, darker green above, and silvery below.
The sides of the head have a pinkish wash, and the lower fins are largely
reddish orange.

Movements in the water of the different species tend to be char-
acteristic. In jumping over a low obstacle, such as a counting board, both
King Salmon and Silver Salmon tend to go over with a sort of rolling
motion, while the steelhead tend to jump straight ahead. Similarly, in
breaking water in a pool the salmons tend to come out with a rolling
motion, while the steelhead usually come out with a straight thrust.

In some instances it has been noted that in leaping the salmons have
extended their pectoral fins fully, while the steelhead have folded them
partially against the body.

The sexes are best distinguished externally by the elongated snout of
the males, by the ' ' razor back ' ' and generally slimmer appearance of the
males, and by the generally cumbersome, roundish appearance of the
females. These characters become marked only as the fish approach
sexual maturitv.

190

CALIFORNIA FISH AND GAME

Recognition of Mutilated Specimens

Another type of problem in recognition is encountered by the law
enforcement officer. Often he obtains as evidence a cleaned fish, or only
part of a fish. To aid in identification in such cases, various characters
possessed by the different species are here summarized and will prove
useful if some of the needed characters given in the key are missing.

Steelhead Rainbow Teotjt :

Cutthroat Tbout :

King Salmon

SiLVEB Salmon

Pink Salmon

Chum Salmon :

Red Salmon

Rays in anal fin usually 9 to 12 (rarely 13) ; pyloric
caeca 42 to 80 ; gill rakers 16 to 22 on first arch ;
branchiostegal rays 10 to 12 ; 115 to 180 oblique rows
of scales crossing the lateral line ; no red dash in cleft
under each side of lower jaw evident in life ; rays in
dorsal fin 10 to 13 (usually 11 or 12) ; hyoid teeth
(those located behind the patch of teeth on tip of
the tongue) always absent. Maximum weight about
80 pounds.

Rays in anal fin 9 to 11 (usually 10) ; pyloric caeca
about 45 ; gill rakers 14 to 21 on first arch ; branch-
iostegal rays 10 to 12; 120 to 180 (usually 150 to
160) oblique rows of scales crossing the lateral line ;
red dash in cleft under each side of lower jaw usually
evident in life ; rays in dorsal fin 8 to 11 (usually 10) ;
hyoid teeth usually present but few and scattered.
Maximum weight about 12 pounds.

Rays in anal fin 15 to 19 ; pyloric caeca 93 to 214 ;
gill rakers 20 to 31 on first arch ; branchiostegal rays
13 to 19 ; about 135 to 155 oblique rows of scales
crossing the lateral line; characterized by' small
black blotches on both lobes of tail. Maximum weight
over 100 pounds, but individuals over 50 pounds .a,re
rare.

Rays in anal fin usually 13 or 14 (rarely 12, 15, 16,
or 17) ; pyloric caeca 45 to 83 ; gill rakers 19 to 25
on first arch; branchiostegal rays 11 to 15 (usually
13) ; about 120 to 145 oblique rows of scales 'crossing
the lateral line; blackish spots on back as a rule
smaller than those in King Salmon, and extending
only to upper lobe of tail. Maximum weight about 27
pounds, but individuals over 15 pounds are rare.

Rays in anal fin 13 to 17; pyloric caeca 165 to 195;
gill rakers 26 to 85 on first arch ; branchiostegal rays
9 to 15 ; about 170 to 240 oblique rows of scales
crossing the lateral line ; large and oblong blackish
blotches on caudal fin. Maximum weight about 10
pounds.

Rays in anal fin 13 to 17 (rarely 12) ; pyloric caeca
135 to 185 ; gill rakers 19 to 26 on first arch ; branch-
iostegal rays 10 to 16 (usually 13 to 15) ; about 120
to 153 oblique rows of scales crossing the lateral
line ; back and sides with no defined spots. Maximum
weight about 30 pounds, but individuals ov€r 15
pounds are uncommon.

Rays in anal fin 13 to 17 (usually 14 or 15) ; pyloric
caeca 66 to 95 ; gill rakers 30 to 50 on first arch ;
branchiostegal rays 11 to 15; about 125 to '145
oblique rows of scales crossing the lateral line. Max-
imum weight about 16 pounds, but individuals over
8 pounds are rare.

NOTES

RARE FISHES TAKEN NEAR LOS ANGELES

The following list ol" fislies is made uj) from records of those rare
and unusual fislies turned over to or ac(|iiired by the California State
Fisheries Laboratorv since the last list published in "Califoi£NIA Fish
AND Game," by J)auglierty, Vol. ;}2, No. ;j, pp. 157-158, July, 1940.

Lathrypnns dalli (Gilbert). Goby : A specimen approximately one
inch in length was taken September 15, 1946, at Emerald Bay, Santa
Catalina Island, in about 20 feet of water by T. S. Davis of Ilermosa
Beach. Mr. Davis while skin diving brought up a barnacle-encrusted
beer bottle with the goby living inside. The fish was too large to be
removed from the bottle and only after it had been dead a couple days
and shrunk in size was it removed without breaking the bottle. This
species attains a length of one and one-quarter inches and has been
reported from Santa Catalina Island in waters as deep as 300 feet. In
life this goby is a very beautiful fish with a bright coral red body bearing
several vertical blue bands which almost meet on the ventral side. Blue
streaks and bands also occur on the head and around the eyes.

Luvarus imjjerialis (Kafinesque). Louvar : On September 29, 1946,
S. E. Edmundson, operator of the mackerel scoop boat "Nahra" brought
in the anterior portion of a femal louvar which had been found floating
on the surface of the ocean approximately 10 miles southwest of Santa
Catalina Island. It had been cut off just behind the insertion of the dorsal
fin, was about two feet long and weighed 48 pounds. The mutilation may
have been the result of sharks attacking the fish. Several louvars have
been taken on the coast from as far north as Monterey but little is known
of the life hisitory or activities of this strange and rare visitor to our
coast. It has previously been reported in "California Fish and Game"
by the following authors : Bolin, Volume 20, Number 3, pp. 282-284, 1
figure, 1940; Croker, Volume 25, Number 3, pp. 252-254, 1939; and
Thompson, W. F., Volume 5, pp. 202-203, 1919.

Enophrijs taurinus (Gilbert). Cottid : This quite rare fish was
found in a load of sardines on the San Pedro seiner ''Clermont" which
made the catch on December 20, 1940, halfway between Santa Cruz and
Santa Rosa Islands in 30 or 40 fathoms of water. The specimen, approxi-
mately four inches in length, had red coloring on the pectoral and pelvic
fins which has not been reported in previously described individuals.

Verrunculiis polylepis (Steindachner), Trigger Fish : A specimen
caught in a trammel net December 23, 1946, just north of the San Cle-
mente pier, was turned over to the laboratory by Morris Souder and
Emery S. (Casey) Jones of the Bayside Fish Market, Newport. The
fish was approximately one foot long, though the species attains a length
of two and one-half feet. It is numerous in Lower California waters but
only a rare visitor as far north as San Pedro. The trigger mechanism of
this species is described by Clothier in "California Fish and Game,"
Volume 25, Number 3, pp. 233-236, 1940.

(191)

192 CALIFORNIA FISH AND GAME

Buvettus pretiosus (Cocco) . Oilfish: One specimen turned over to
the laboratory by the skipper and crew of the seiner " Sparton" was
caught in a blufin tuna haul near Guadalupe Island, Lower California,
in 50 fathoms of water January 28, 1947. The fish was 49 inches in length
and weighed 34 pounds. This is apparently the second known record
of this species from the eastern Pacific. It has also been recorded from
the two sides of the Atlantic, the East Indies, Hawaii, Japan, South
Africa, and various South Sea Islands. The other specimen is recorded
from our coast by Barnhart and Hubbs in ' ' California Fish and Game, "
Volume 30, Number 1, pp. 52-53, 1 illustration, 1944.

v"
'?*,

!C~ .. t '^/^

i-fe.**"^

NCH

Figure 5 8. Young Black Sea-bass, Stereolepis gigas. Photo
by Haden and Carpenter, San Pedro

Stereolepis gigas (Ayres). Black Sea-bass ; Jewfish : A small black
sea-bass, approximately three and one-half inches long, was found in
a load of Pacific mackerel taken by the seiner "St. Augustine" about
seven miles off the town of San Clemente on the night of February 24,
1947. The black sea-bass known to most people is a veritable giant of
a more or less dull blackish color. This young specimen was a brick red
color with black spots over the body which gave a polka-dot effect. Local
fishermen report that they often see young black sea-bass in and around
the kelp beds. A decription of the change in color and form which occur
with growth in this species is given by Higgins in "California Fish
AND Game, ' ' Volume 6, Number 1, pp. 5-6, illustrated, 1920.

John E. Fitch, Bureau Marine Fisheries,
California Division Fish and Game, March, 1947.

IN MEMORIAM
JOHN H. DAVIS

John II. Davis, probably the oldest of the old-timers of the California
Fish and Game Commission, died early in 1947 in San Francisco at the
age of 90.

For approximately 25 years, spanning the centuries, Mr. Davis
served as a deputy. He was a license collector from Crescent City to San
Diego and later was on the patrol boats. It is said he named the first
"Quinnat" and it is known he was her first skipper.

Mr. Davis told many interesting stories of exciting experiences in
his w'ork for the commission. One related how he hid on shore, in the
midnight darkness, nnder the willows of the Noyo River, to reach out
and nab Phil Roselle, an early-day poacher as he came singing in his
boat to take in his illegal net. When Roselle, described by Mr. Davis
as the "arch-conspirator of the Noyo" went to the county jail to serve
his time, the sheriff regretted the end of his sentence, because he turned
out to be the best cook the jail ever had !

At another time Mr. Davis stopped a Salvation Army parade on
San Francisco's Embarcadero to arrest the bass drummer, whom he
recognized as a wanted violator. The band played on without its big drum.

With horses and wagon, he hauled hatchery trout in milk cans from
the railroad at Merced to plant them in the waters of Yosemite. He
directed the planting of black bass in the Russian River.

A postmaster in the Napa district tipped him off that he could
find out-of-season hunters in a nearby area. Davis went to another
area and found that same postmaster violating the game law.

Mr. Davis had many friends among the older commercial fishermen.
In later years, after retirement, one of his great joys was to visit Fisher-
man's Wharf at San Francisco and hobnob with the first-generation
crab fishermen, talking Italian and waving his arms, too. He could speak
Spanish, Portuguese and seven Italian dialects.

A Chinese fisherman testified falsely against Mr. Davis in court.
Later, when the latter chugged up in the patrol boat to visit the Oriental's
camp at McNear's Point, the conscience-stricken Chinaman hid in a
shack during the deputy 's stay. The man wms ostracized by his fellows.

John Davis served under four California Governors — James H.
Budd, Henry T. Gage, George C. Pardee, and Hiram W. Johnson. On
the commission he served under John P. Babcock and Charles A. Vogel-
sang, Chief Deputies; and worked with Manuel Cross, Hugh Walters,
Walter Welch, and Alonzo Lea, brother of Congressman Lea.

For many years he resided at San Pablo, California, where, for a
period, he was constable. Family tradition has it his father and mother
were the first white couple married in Oakland. He was born at Stege.

Mr. Davis retired some 40 years ago and is survived by eight
daughters, eight grandchildren, and eight great grandchildren. His wife
preceded him in death in 1940. — Samuel Hawkins, San Francisco, March,

1947.

(193)

194 CALIFORNIA FISH AND GAME

GEORGE NEALE

George Neale, former employee and executive officer of the Division
of Fish and Game, passed awav at his home in Sacramento, November
30, 1946.

Mr. Neale was born in London, England, October 9, 1857. He came
to the United States in 1876 making his home in Sacramento where
he engaged in private business. He was naturalized in Sacramento in
July, 1880, by Judge Denson of the superior court.

Always an ardent hunter and fisherman, he was interested in the
protective laws and was made county game warden in Sacramento in
January, 1903. A few weeks later, in April, he was given an appoint-
ment as warden by the then Chief Deputy, Charles A. Vogelsang.

With the appointment of Frank Newbert on the commission in 1911,
Neale was placed in charge of the Sacramento office and in March, 1922,
was appointed executive officer, resigning in December, 1925. He again
entered the service of the division in August, 1928, and later was put
in charge of the Bureau of Fish Rescue work, resigning in August, 1934.

He is survived by his widow, Ada Roberts Neale, and by several
nieces in England. — J. S. Hunter, Chief, Bureau of Game Conservation,
California Division of Fish and Game, May, 1947.

WALTER R. KRUKOW

On April 20, 1947, while on patrol duty on Boulder Creek, 16 miles
west of Redding, Fish and Game "Warden Walter R. Krukow was shot
and instantly killed by Sanford L. Johnson, a 17-year old high school
student who was fishing for trout during the closed season.

According to the youth's own statement, the warden warned him
to cease fishing and to wait until the first of May, the legal opening date.
Johnson then traveled several miles on foot to his residence, procured
a rifl^e and ammuniton and returning to Boulder Creek shot Warden
Kurkow from ambush to prcA^ent the arrest of his fishing partner for a
similar game law violation. The j^outh is in jail at Redding awaiting trial.

Walter R. Krukow was born at San Pedro, California, on May 28,
1905, and graduated from Glendale High School. He went into business
for himself as a landscape gardener prior to joining the division March
23, 1937, as an assistant warden. He served in Southern California prior
to his assignment in Shasta County and was promoted warden March 1,
1944.

He leaves a widow, a young son and an infant daughter in Redding,
as well as a sister in Southern California. To these innocent victims of
a needless tragedy we wish to extend our deepest sympathy. — E. L.
Macaulay, Chief, Bureau of Patrol, California Division of Fish and
Game, June, 1947.

REPORTS

FISH CASES
January, February, March, 1947

Offense

iViimhcr
arrcsta

Fines
imposed

Jail

sentences

(days)

Abaloiie: tnkinc from shell below high water, taking to sell commercially, under-
sized, ovcrlimit, no license -

Angling: using set lines, no license, more than one rod, possession gaff 300 feet
stream, illoKal net, within 150 feet dam, closed area, near fish ladder, transfer
license, with hand line

Bass: undorsi/e, ovcrlimit, more than one rod, night fishing, possession for sale..

Catfish: undersized, ovcrlimit, selling and purchasing, undersized

Crappio: Ovcrlimit

Claras: undersized, ovcrlimit, without license, in refuge..

Commercial: no license; receivins and selling fish taken closed season; gill net
Dist. 11; purse seine Dist. XX; failure to keep trawler log; untagged fish

Crabs: undersize, taking on Sunday

Lobster: closed .season, undersize, traps, closed district, oversize

Pollution _

Salmon: undersize, within 150 feet of dam, snagging, taking in spawning area,
shore limit, spe irina, spearing closed area, drift gill net, shooting, gaffing, illegal
posses,sion, taking in Dist. XII

Sunfish : closed season

Trout: untagged, ovcrlimit, set lines, chumming, closed area, closed season, snag-
ging, with spear at night

Totals..

107

13
3

528

$2,450 00

3,722 .50

1,007 .50

525 00

50 00

2,762 00

2,025 00

1.930 00

215 00

350 00

Sin 00

75 00
1,460 00

$17,382 00

750

491H

52SJ2

GAME CASES
January, February, March, 1947

Offense

Number
arrests

Fines
imposed

JaU

sentences
(days)

Beaver..

1
8

87
1

17
6

105
14

70
16
31
2
3
2
5

$50 00
200 00

4,105 00

3,121 00

200 00

3,607 50

10 00

770 00

125 00

2,714 00
655 00

4.332 00
435 00
950 00
60 00
75 00
65 00
55 00

Coots: Closed season . . . .

Deer: closed season, illegal possession, unmarked, female, spike buck, take in
refuge, altering tag, transferring tag, spotlighting, killing fawn, taking forked
horn, 22 rifle

500

Deer meat: illegal possession, unstamped

139H

Doves: Closed se.ason, ovcrlimit, no license .

Ducks: Closed season, ovprliniit, shooting from motor boat, offering for sale,
game refuge, with 22 rifle, after hours

Grebe

Geese: ovcrlimit, with automobile, after legal hours, with shotgun

Grev squirrel

Hunting: no license, night hunting with spotlight, from motor vehicle, unplugged
gun, in refuge, closed season, citizen's license, shooting from motor boat, after
legal hour, nonresident with resident license .. . .

Non-game birds...

Pheasants: hen, closed season, no license, shooting from automobile, before
hours, taking with gun holding more than three shells

191

Quail: closed season, ovcrlimit

Rabbits: taking at night, closed season, no license, operating snares

Shore birds

Swans

Taking fur bearing mammals without license ...

Trapping; no license, nonresident

Totals

452

$21,529 50

863.4

(195)

196 CALIFORNIA FISH AND GAME

SEIZURES OF FISH AND GAME
January, February, March, 1947

Fish

Abalone- 549

Abalone, pounds 1>237J^

Bass 56

Bass, pounds 734

Catfish, pounds 150

Clams 1,327

Crab 180

Crappie 14

Lobster 128

Lobster, pounds 424J-^

Salmon 7

Trout 38

Trout, pounds ,_.. 2,027

Game

Coots 21

Deer 11

Deer, pounds... 1,158

Doves 10

Ducks . 107

Geese 58

Non-game birds 9

Pheasants 49

Quail 98

Rabbits 20

Shorcbird': 4

83418 12-17 300

STATE OF CALIFORNIA

DEPARTMENT OF NATURAL RESOURCES

DIVISION OF FISH AND GAME
SAN FRANCISCO. CALIFORNIA

Personnel

OFFICE OF ADMINISTRATION

EMITj J. N. OT r, .TR., ICxoculivc iJirector . S.icianiento and San Francisco

William II. Uoslwiclc, Supervisor of Conservation lOducatiori Sairaniento

Robert K. Itctcly, Administrative Aid Sacramento

BUREAU OF FISH CONSERVATION

A. C. TAFT, Cliiof San Francisco

EAUL, LI'^ITIUTZ, Supervisor of Fish Hatcheries San P'ranclsco

J. William t'uoU. Assistant Supervisor of l-'ish Hatcheries San I'rancisco

Kdward Clessen, Foreman, UrooUdaie Hatchery Brookdale

Carl FreyscliIaK, Foreman, Central Valleys Hatchery Elk (Jrove

SlepluMi Sniedlcy, l^'orenuin, I'lairie Ci eek Hatchery Orick

R. C. Lewis, Assistant Suiiervisor of Fish Hatcheries l-'resno

Ross McChiud, i>'oi'eman, liasin Creek Hatchery Tuolumne

A. N. Culver, Foreman, Kavveah Hatchery Three Rivers

Cecil Ray, Foreman, Kern River Hatchery Kernville

C. Ij. l'"rame, l''orenian. Kings River Hatchery Fresno

L. K. Nixon. Foreman, Yosemite tiatchery Yosemlte

G. S. tiunderson, Fish Hatcheryman, Sequoia Hatchery Exeter

Terence Potter, Fisli Hatcheryman, Moorehouse Spring Hatchery

Camp Nelson

Allan Pollitt, Assistant Supervisor of Fish Hatcheries Tahoe City

Harold E. Roberts, Foreman. Mt. Tallac Hatchery Camp Richardson

William Fiske, Foreman, Feather River Hatchery Clio

Harry Cole, Foreman, Yuba River Hatchery Camptonvllle

George McCloud, Assistant Supervisor of Fish Hatcheries Mt. Shasta City

Preston Bills, Foreman, Mt. Shasta Hatchery Mt. Shasta City

James Hinze, Foreman, Fall Creek Hatchery Copco

D. A. Clanton. Assistant Supervisor of PMsh Hatcheries Fillmore

C. W. Chansler, Foreman, Fillmore Hatchery Fillmore

Donald Evins, Foreman, Mojave River Hatchery Victorville

Byron Unruh, Fish Hatcheryman, Whittier Hatchery Whittier

Leon Talliott, Assistant Supervisor of Fiah Hatcheries Independence

William O. White, Foreman, Hot Creek Hatchery Bishop

Carleton Rogers, Foreman, Black Rock Ponds Independence

M. O. Talbott, Foreman, Mt. Whitney Hatchery Independence

Harold Hewitt, Assistant Supervisor of Fish Hatcheries Burney

John Marshall, Foreman, Lake Almanor Hatchery Westwood

BRIAN CURTIS, Supervising Fisheries Biologist San Francisco

Joseph Wales, District Fisheries Biologist Mt. Shasta

Harry Hanson, Senior Fisheries Biologist Red Bluff

E. W. Murphey, Fish Hatcheryman, Stream Improvement Yreka

William A. Dill, District Fisheries Biologist Fresno

Scott Soule, Junior Aquatic Biologist Fresno

C. K. Fisher, Jr., Junior Aquatic Biologist F'resno

Leo Shapovalov, District Fisheries Biologist Stanford University

Garth I. Murphy, Junior Aquatic Biologist Lakeport

Alex Calhoun, Senior Fisheries Biologist San Francisco

Chester Woodhull, Junior Aquatic Biologist Stockton

J. C. Eraser, Junior Aquatic Biologist San Francisco

H. P. Chandler, Junior Aquatic Biologist San Francisco

Elden Vestal, Senior Fisheries Biologist June Lake

R. V. Beck, Junior Aquatic Biologist June Lake

Willis A. Evans, Senior Fisheries Biologist -- Whittier

John Maga, Assistant Sanitary Engineer San Francisco

BUREAU OF GAME CONSERVATION

J S. HUNTER, Chief San Francisco

BEN GLADING, Assistant Chief San Francisco

R. E. Curtis, Game Manager in Charge San Francisco

R. N. Hart, Assistant Game Manager San FYancisco

A. L. Hensley, Assistant Game Manager San Francisco

Nathan Rogan, Assistant Game Manager San Francisco

L. H. Cloyd, Game Manager Gridley

J. B. Cowan, Assistant Game Manager Gridley

R. R. Noble, Assistant Game Manas^er Gridley

R. M. Wattenbarger, Assistant Game Manager Los Banos

J. D. Stokes, Game Manager Alturas

G. L. Bolander, Assistant Game Manager Alturas

James H. Gilman, Assistant Game Manager Red Bluff

Verne F. Fowler, Assistant Game Manager Wendel

R. M. Bushey, Sr., Assistant Game Manager Madeline

Robert Lassen, Assistant Game Manager Doyle

D. M. Selleck, Game Manager King City

Fred T. Ross, Assistant Game Manager, Federal Aid Project 26D_Halcyon

BUREAU OF GAME CONSERVATION— Continued

John Laughlin, Game Manager Riverside

C. R. Kniglit, Assistant Game Manager Calipatria

R. L. Reedy, Assistant Game Manager Calipatria

W. P. Dasmann, Game Range Teclmician San Francisco

D. D. IilcLean, Game Biologist San P'rancisco

J. E. Chattin, Game Biologist Berkeley

D. F. Tillotson, Assistant Game Biologist, Federal Aid Project 25R

Berkeley

J. F. Ashley, Game Biologist San Francisco

H. A. Hjersman, Assistant Game Biologist San Francisco

H. Twining, Assistant Game Biologist, Federal Aid Project 22R Chico

C. M. Herman, Parasitologist Berkeley

J. R. Wallace, Supervisor, Predatory Aninial Control San Francisco

G. McNames, Supervising Hunter and Trapper Redding

George Seymour, Supervising Hunter and Trapper Sacramento

O. R. Shaw, Supervising Hunter and Trapper King City

N. J. Jeffries, Supervising Hunter and Trapper Monrovia

Carlisle Van Ornum, Supervisor, Game Farms San Francisco

Fred Hein, Game Farm Foreman -_ Fresno

Eugene D. Piatt, Game Farm Superintendent Yountville

George H. Metcalfe, Game Farm Foreman Yountville

Val H. Francis, Game Farm Superintendent Los Serranos

Richard B. Kramer, Game Farm Foreman Los Serranos

BUREAU OF MARINE FISHERIES

RICHARD S. CROKER, Chief — San Francisco

S. H. DADO, Assistant Chief San Francisco

B. R. Saunders, Auditor San Francisco

Frances N. Clark, Senior Aquatic Biologist Terminal Island

Donald H. Fry, Jr., Senior Aquatic Biologist Modesto

W. L. Scofield, Senior Aquatic Biologist Terminal Island

John F. Janssen, Jr., Associate Aquatic Biologist Terminal Island

J. B. Phillips, Associate Aquatic Biologist Pacific Grove

"William E. Ripley, Associate Aquatic Biologist Stanford University

J. A. Aplin, Assistant Aquatic Biologist .Stanford Unis-ersity

Paul Bonnot, Assistant Aquatic Biologist Stanford University

Charles R. Clothier, Assistant Aquatic Biologist Terminal Island

H. C. Godsil, Assistant Aquatic Biologist Terminal Island

Howard H. McCully, Assistant Aquatic Biologist Stanford University

Phil M. Roedel, Assistant Aquatic Biologist Terminal Island

John G. Carlisle, Jr., Junior Aquatic Biologist Pacific Grove

Robert D. Collyer, Junior Aquatic Biologist Terminal Island

Keith W. Cox, Junior Aquatic Biologist Pacific Grove

Anita E. Daugherty, Junior Aquatic Biologist Terminal Island

John E. Fitch, Junior Aquatic Biologist Terminal Island

Richard J. Hallock, Junior Aquatic Biologist Sacramento

Edwin K. Holmberg, Junior Aquatic Biologist Stanford University

Eldon P. Hughes, Junior Aquatic Biologist Berkeley

Robert C. Wilson, Junior Aquatic Biologist Terminal Island

Parke H. Young, Junior Aquatic Biologist Terminal Island

Geraldine Conner, Fisheries Statistician Terminal Island

Lars J. Weseth, Captain, M. V. "N. B. SCOFIELD" Terminal Island

Robert Mills, Engineer, M. V. "N. B. SCOFIELD"___Terminal Island

Peder Stockland, Boatswain, M. V. "N. B. SCOFIELD"

Terminal Island

Harry A. Peters, Radioman, M. V. "N. B. SCOFIELD"

Terminal Island

BUREAU OF LICENSES

H. R. DUNBAR, Chief -- Sacramento

C. LAWRENCE O'LEARY, Assistant Chief Sacramento

Emil Dorig, Senior Account Clerk, Licenses San Francisco

Enid L. Mullen, Intermediate Account Clerk, Licenses Redding

Ren E. Nickerson, Supervising Account Clerk Grade 1, Licenses Los Angeles

ACCOUNTS AND DISBURSEMENTS

D. H. BLOOD, Deputy Director and Comptroller Sacramento

E. ARONSTEIN, Accounting Officer Sacramento

BUREAU OF PATROL

E. L. MACAULAY, Chief of Patrol__-- San Francisco

H. C. JACKSON, Assistant Chief of Patrol (Training Officer) Los Angeles

A. L. Reese, Warden-Pilot Sacramento

North Coast District

WILLIAM J. HARP, Assistant Chief San Francisco

LESLIE E. LAHR, Captain, Humboldt and Del Norte Counties Eureka

Otis Wright, Warden, Del Norte County -- Crescent City

Jack Finigan, Warden, Humboldt County Areata

Larry Werder, \Varden, Humboldt County Eureka

William F. Kaliher, Warden, Humboldt County -- I^^ortuna

Robert Perkins, Warden, Humboldt County Garberville

BUREAU OF PATROL— North Coast District— Continued

SCOTT FKLAND, Caritiiln, Mondocino and Lake Counties- "*rt

Jack Sawyer, Warden, I^ake County.. "

]Ji)U^;l!is Dowcll, Wuriicn, hake <,'nunty__

Ovid Jlolmos, Warden, Mendocino Ooimty

Flovd i^(i<;tH, Warden, Mendocino County

Oarri.' lleryford. Warden, Mendoeino County

J. G. McKorlie, Warden, Mendoc^liio (bounty i

LEK C. SIIIOA, Cnptain, Sonoma, Marin and Napa Counties •'

T;,iy Jiruor, Warden, Sonoma (bounty - — -— — -

lliiloy CirovcH, Warden, Sonoma County -, .

BerL Laws, Warden, Sonoma County

R. J. Yates, Warden, Marin County

M. P. Joy, Warden, Napa County . ;

Karl Lund, Warden, Napa (bounty Nai>a

T. W. SCHILLING, Captain, San Francisco, San Mateo, Alameda and Contra Costa

Counties San Fr:

C. R. Peek, Warden, San Mateo County Burl

Chas. KaniR, Warden, San Francisco County San Vrnw i>.- •>

J. W. Uarbuck, Warden, Contra Costa County Antloch

James Ruetffen, Warden, Alameda County Martinez

RALPH CLASSIC, Captain, Monterey, San Benito, Santa Cruz and Santa Clara

Counties Monterey

Fred H. Post, Warden, Monterey County Salinas

Owen Mello, Warden, Monterey County Monterey

Warren Smith, Warden, Monterey County Klnp City

J. P. Vissiere, Warden, San Benito County HolUster

C. E. Holladay, Warden, Santa Clara County San Jose

R. A. Tinnin, Warden, Santa Clara County Morgan Hill

P. J. McDermott, Warden, Santa Cruz County Santa Cruz

Northeast District

A. A. JORDAN, Assistant Chief Redding

William Royston, Warden, Siskiyou County Tulelake

Louis Olive, Warden, Siskiyou County Yreka

Delmor Baxter, Warden, Modoc County Nubieber

Don Davison, Warden, Modoc County Alturas

Bert Mann, Warden, Shasta County Redding

Don Chipman, Warden, Siskiyou County Dunsmulr

Harold Erwick, Warden, Tehama County Corning

R. W. Anderson, Warden, Tehama County Red Bluff

Arthur Barsuglia, Warden, Siskiyou County Fort Jones

C. L. Gourley, Warden, Trinity County Weaverville

W. D. Hoskins, Warden, Shasta County McArthur

North Valley District

C. S. BAUDER, Assistant Chief Sacramento

JOSEPH H SANDERS, Captain Sacramento

Albert Sears, Warden, El Dorado County Placervllle

William Hoppe, Warden, San Joaquin County --Lodi

Charles Sibeck, Warden, Sacramento County Sacramento

Eugene Durney, Warden, Sacramento County Sacramento

C. O. Pisher, Warden, Yolo County Woodland

R. E. Tutt, Warden, Solano County Dixon

Ed. Hughes, Warden, Sacramento County Sacramento

H. S. Vary, Warden, Sacramento County Sacramento

W. B. Bradford, Warden, San Joaquin County Stockton

A. H. WILLARD, Captain Rocklin

Nelson Poole, Warden, Placer County Auburn

William LaMarr, Warden, Placer County Tahoe City

Earl Hiscox, Warden, Nevada County Nevada City

Taylor London, Warden, Colusa County Colusa

Hal Waggoner, Warden, Sutter County Sutter City

Edward Dennett, Warden, Yuba County Wheatland

E. O. WRAITH, Captain Chico

L. E. Mercer, Warden, Butte County Chico

Chester Ramsey, Warden, Butte County Oroville

Rudolph Gerhardt, Warden, Butte County Gridley

L. M. Booth, Warden, Lassen County — Susanville

Paul Kehrer, Warden, Plumas County Greenville

George Shockley, Warden, Plumas County Portola

James Hiller, Warden, Glenn County — Willows

T. O. Borneman, Jr., Warden, Lassen County Chester

South Valley District

S. R. GILLOON, Captain Fresno

R. J. Little, Warden, Amador County Pine Grove

L. R. Garrett, Warden, Calaveras County Murphys

C. L. Brown, Warden, Fresno County Coalinga

R. J. O'Brien, Warden, Fresno County Clovis

Gilbert T. Davis, Warden, Fresno County Reedley

Lester Arnold, Warden, Kern County Bakersfield

Donald Hall, Warden, Kern County Kernville

Ray Ellis, Warden, Kings County — Hanford

H. E. Black, Warden, Madera County Madera

Hilton Bergstrom, Warden, Merced County Los Banos

BUREAU OF PATROL— South Valley District — Continued

George Magladry, Warden, Stanislaus County Modesto

W I. Long, Warden, Tulare County ^f;--^^ •,,

Hoswell C. Welch, Warden, Tulare County Porterville

F. P. Johnston, "\Varden, Tuolumne County ^^°'^°'^^

R. Switzer, Warden, Merced County — Merced

Southern District

EARL MACKLIN, Assistant Chief Los Angeles

WALTER SHANNON, Captain Los Angeles

L R. Metzgar, Warden, Los Angeles County L^s Angeles

A. F. Stager, Warden, Los Angeles County Pomona

Fred Albrecht, Warden, Los Angeles County Los Angeles

Walter F. Emerick, Warden, Los Angeles County Palmdale

Theodore Jolley, Warden, Los Angeles County ^^__Norwall£

C. L. Towers, T^^arden, Los Angeles County Los Angeles

Otto Rowland, Warden, San Bernardino County __Victorville

W C. Malone, Warden, San Bernardino County San Bernardino

Erol Greenleaf, Warden, San Bernardino County Big Bear Lake

Leo Rossier, Warden, San Bernardino County -^^^f?^

George Werden, Jr., Warden, Riverside County Blyme

W. C. Blewett, Warden, Riverside County . -Indio

Cliff Donham, Warden, Riverside County Idyllwiid

William H. Jolley, Warden, Riverside County K,Isinore

R. L. Eraser, Warden, Riverside County .Banning

WILLARD GREBNWALD, Captain La Mesa

James Reynolds, Warden, Imperial County Brawley

Henry Shebley, Warden, San Diego County Escondido

Henry Ocker, Warden, San Diego County f — ^iv^^"^

Frank Bartol, Warden, San Diego County -— .L-^^ Mesa

F. W. HECKER, Captain San Luis Obispo

Orben Philbrick, Warden, San Luis Obispo County Paso ivopies

Vincent Dona, Warden, San Luis Obispo County San Luis Obispo

R. E. Bedwell, Warden. Santa Barbara County Santa Barbara

H. L. Lantis, Warden, Santa Barbara County Santa Maria

Leslie F. Edgerton, Warden, "Ventura County FiUrnore

John Spicer, Warden, Ventura County -Ojai

HOWARD SHEBLEY, Captain Independence

A. F. Crocker, Warden, Inyo County ^tv?,^?^ j^®

Henry J. Bartol, Warden, Inyo County Little Lake

James Loundigan, Warden, Inyo County VT"^ °?

W. S. Talbott, Warden, Mono County Bridgeport

Robert Stedman, Warden, Mono County__ Leevmmg

MARINE PATROL

L. F. CHAPPELL, Assistant Chief of Patrol San Francisco

RALPH CLASSIC, Captain Monterey

Ellis Berry, Warden — Monterey

E. R. Hyde, Warden ^^rMonterey

J. Ross Cox, Warden WatsonviUe

LESLIE E. LAHR, Captain Eureka

Walter Grey, Warden •- ^--Eureka

T. W. SCHILLING, Captain --San Francisco

Ralph Dale, Captain Patrol Boat Greenbrae, San Rafael

Kenneth Hooker, Warden r°J^^2

Bolton Hall, Warden _ Antioch

Ralph Miller, Warden San Francisco

G. R. Smalley, Warden Richmond

Glenn Whitesell, Warden —Stockton

TATE MILLER, Captain Terminal Island

N. C. Kunkle, Warden Newport Beach

Carmi Savage, Warden Santa Monica

R. C. Schoen, Warden Terminal Island

Niles J. Millen, "Warden Terminal Island

Donald Glass, Warden —Terminal Island

John Barry, Warden Terminal Island

Will Payne, Warden Terminal Island

Robert Kaneen, Warden Terminal Island

Jacob Meyer, Warden ^^Newport

Thomas J. Smith, Warden San Diego

Frank Felton, Warden San Diego

Lester Golden, Warden Arroyo Grande

MARINE PATROL BOATS

Cruiser Bonita Catalina Warden Millen

Cruiser Yelloiotall -San Pedro Warden Glass

Cruiser Broadbill Newport Warden Meyers

Cruiser Grunion Santa Monica Warden Savage

Crui.ser Perch San Rafael Captain Dale

Cruiser RainJ)ow III Antioch Warden Hall

Cruiser Tyee Stockton Warden Whitesell

Cruiser Bass Lake Millerton Captain Gilloon

Cruiser Shasta Redding —Warden Mann

Launch Minnow Clear Lake Warden Sawyer

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