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GMJFORNIA
FBH'-GAME

"CONSERVATION OF WILDLIFE THROUGH EDUCATION"



f VOLUME 69


JULY 1983


NUMBER 3 J




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California Fish and Game is a journal devoted to the conservation of wild-
life. If its contents are reproduced elsewhere, the authors and the California
Department of Fish and Game would appreciate being acknowledged.

Subscriptions may be obtained at the rote of $5 per year by placing an
order with the California Department of Fish and Gome, 1416 Ninth Street,
Sacramento, California 95814. Money orders and checks should be made out
to California Department of Fish and Game. Inquiries regarding paid sub-
scriptions should be directed to the Editor.

Complimentary subscriptions are granted, on a limited basis, to libraries,
scientific and educational institutions, conservation agencies, and on exchange.
Complimentary spbscriptions must be renewed annually by returning the post-
card enclosed with each October issue.



Please direct correspondence to:

Perry L. Herrgesell, Ph.D., Editor
California Fish and Game
1416 Ninth Street
Sacramento, California 95814



u



VOLUME 69



JULY 1983






I]



V



NUMBER 3




Published Quarterly by

STATE OF CALIFORNIA

THE RESOURCES AGENCY

DEPARTMENT OF FISH AND GAME

—LDA—



CALIFORNIA FISH AND CAME



STATE OF CALIFORNIA
GEORGE DEUKMEJIAN, Governor



THE RESOURCES AGENCY
GORDON VAN VLECK, Secretary for Resources



FISH AND GAME COMMISSION

NORMAN B. LIVERMORE, JR., President

San Rafael

WILLIAM A. BURKE, Ed.D., Vice President ABEL C. GALLETTI, Member

Los Angeles Los Angeles

BRIAN J. KAHN, Member ALBERT C. TAUCHER, Member

Santa Rosa Long Beach



DEPARTMENT OF FISH AND GAME
Howard D. Carper, Director

1416 9th Street
Sacramento 95814



CALIFORNIA FISH AND GAME

Editorial Staff

Editorial staff for this issue consisted of the following:

Wildlife Bruce Browning, Ronald M. Jurek

Marine Resources Robert N. Lea

Anadromous Fisheries David Hoopaugh

Inland Fisheries Jack Hansen, Ronald J. Pelzman

Environmental Services Kim McCleneghan

Editor-in-Chief Perry L. Herrgesell, Ph.D.



CONTENTS

Page
Seasonal Foods of Black Bears in Tahoe National Forest, Cali-
fornia William E. Grenfell, Jr. and Allan J. Brody 132

An Annotated Check List of the Amphibians and Reptiles of
California Mark R. Jennings 151

Northern Occurrences of the Sea Snake, Pelamis platurus, in
the Eastern Pacific, With a Record of Predation on the Spe-
cies George V. Pickwell, Robert L. Bezy, and John E. Fitch 172

Thelophania contejeani Parasitism of the Crayfish, Pacifas-
tacus leniusculus, in California Darlene McCriff and John Modin 178

Notes

Food Habits of Coyotes, Canis latrans, in Eastern Tehama
County, California Reginald H. Barrett 184

A Study of the Effects of Bolero 10G®on the Mountain Garter
Snake, Thamnophis elegans elegans E. E. Littrell 186

Smoked Aluminum Track Plots for Determining Furbearer Dis-
tribution and Relative Abundance Reginald H. Barrett^ 188

Avian Cholera in an American Flamingo, Phoenicopterus ru-
ber: A New Host Record ..Christopher J. Brand and Ruth M. Duncan 190

Reproduction of Arctic Grayling, Thymallus arcticus, in the
Lobdell Lake System, California Richard W. Rieber 191



ERRATUM

Gotshall, D. W., G. H. Allen and R. A. Barnhart. 1 980. An annotated checklist
of fishes from Humboldt Bay, California. Calif. Fish Game, 66(4):220-232.

Page 223, Appendix 1 . The Bay maximum size of Notorynchus maculatus
should read 149Kg ** and not 14.9Kg **.



1 32 CALIFORNIA FISH AND CAME

Calif. Fish and Came 69 ( 3 ): 1 32-1 50 1 983

SEASONAL FOODS OF BLACK BEARS
IN TAHOE NATIONAL FOREST, CALIFORNIA^

WILLIAM E. GRENFELL, JR. and ALLAN J. BRODY'

California Departnnent of Fish and Ganrie

1701 Nimbus Rd., Rancho Cordova, CA 95670

Black bear, Ursus americanus, food habits were determined by analyzing 395 fecal
samples collected from 1978 through 1980. Colonial insects were eaten consistently
throughout the year, while other animal food items were used sporadically. Con-
sumption of plant material varied with phenology. Grasses and forbs were utilized
in the spring, manzanita berries in the summer, and acorns eaten in the fall.

INTRODUCTION

This report is a three-year summary of food habits work conducted in the
Tahoe National Forest between 1978 and 1980. Knowledge of food habits is
becoming increasingly important to land managers concerned with wildlife val-
ues and management plans. This research will be used to validate or update
information currently being used by the USDA Forest Service (USFS) and the
California Department of Fish and Game (CDFG) in their Wildlife/Habitat
Relationships Programs.

Black bear, Ursus americanus, food habits in California have been studied by
several researchers. Studies have been conducted in the San Bernardino Na-
tional Forest (Boyer 1976), Sequoia National Park (Goldsmith et al. 1981),
Yosemite National Park (Graber and White 1978, Graber 1982), and the Shasta-
Trinity National Forest (Piekieiek and Burton 1975, Kelleyhouse 1975). Studies
in other western states have been conducted in Alaska (Hatler 1972), Washing-
ton (Poelkerand Hartwell 1973) and Montana (Tisch 1961).

STUDY AREA

The study area, approximately 287km^ is located on the west slope of the
Sierra Nevada range about 1 1 km, west of Lake Tahoe in Placer County, Califor-
nia (Figure 1). Ownership of the land is partitioned, checkerboard fashion,
between private holdings and the USFS. The majority of the public land is
administered by the Tahoe National Forest, Foresthill Ranger District. A small
portion along the southern boundary of the study area is in the Georgetown
Ranger District, El Dorado National Forest. Elevations range between 1100 m in
Royal Gorge to 2560 m at Mt. Mildred. A state game refuge occupies about 50%
of the study area. The entire area consists of sharp ridges that are divided by
steep canyons and gorges. The North and Middle forks of the American River
and the Rubicon River drain the study area to the west. The Middle Fork of the
American and the Rubicon are dammed at the western edge of the study area
and form French Meadows and FHell FHole reservoirs, respectively.

Average annual precipitation ranges from 1 50 to 1 80 cm, 80% of which occurs
between November and May, mostly in the form of snow. Intense summer
thunderstorms are common. Precipitation during the winter of 1977-78 was

' Supported by Federal Aid in Wildlife Restoration Project W-52-R, "Food Habits Investigations". Accepted May

1982.
' Mr. Brody's current address is Rt. 1, Box 1491, Davis CA 95616.



SEASONAL FOODS OF BLACK BEARS



133



130% of normal, 90% of normal in 1978-79, and 100% of normal in 1979-80
(H. Baer, Placer Co. Water Agency, pers. commun.).

Habitat types found within the study area are mountain meadow, black oak
woodland, chaparral, riparian deciduous, mixed conifer, lodgepole pine, and red
fir (Verner and Boss 1980).

The most abundant mast-producing plants are black oak, Quercus kelloggii;
canyon live oak, Q. chrysolepsis; whiteleaf manzanita, Arctostaphylos viscida;
green-leaf manzanita, A. patula; pinemat manzanita, A. nevadensis; bitter cherry,
Prunus emarginata; and Sierra gooseberry, Ribes roezlii. Oaks are most com-
monly found in canyons below 1500 m. Bitter cherry occurs above 1200 m on
slopes and along streams. Manzanita is found throughout the study area in
association with open stands of oak and conifers, but also occurs in, and often
dominates, chaparral ecosystems. Sierra gooseberry is most abundant in areas
disturbed by logging activity, such as skid trails, roadsides, and clearcuts.




FIGURE 1. Black bear study area, Tahoe National Forest, California.



134 CALIFORNIA FISH AND CAME

Herbaceous cover typical of the study area includes grasses, Poaceae; brack-
en fern, Pteridium aquilinum; clover, Trifolium spp.; lotus, Lotus spp.; larkspur,
Delphinium spp.; corn lily, Veratrum californicum; lupine, Lupinus spp.; lovage,
Ligusticum gray/; and mule ears, IVyethia mollis. Most herbaceous growth is
found in meadows, riparian areas, along roadsides, on skid trails, and in clearcuts
and open conifer woodlands.

Approximately 75% of the study area is composed of commercial conifers,
most of which have been selectively harvested since 1970. Clearcutting has
occured as well. Parcels collectively less than two sections were harvested
during the early 1960s. Logging activity was low in 1979 and high in 1980. Less
than 400 ha of commercial conifer are virgin. The remaining portion of the study
area includes steep, rocky slopes with mountain chaparral and/or oaks and
barren areas.

Annually, about 250 head of beef cattle are grazed throughout the study area
between 1 July and 1 5 October. Sheep are grazed in upper Picayune Valley along
the eastern periphery of the study area for a 2-wk period in August.

METHODS

Between June 1978 and October 1980, 395 black bear scats were collected.
Scats were preserved in 10% formalin, labeled, and forwarded to the California
Department of Fish and Game, Wildlife Investigations Laboratory, Sacramento,
California.

During 1979, species area curves (Brower and Zar 1977) for food items were
constructed for each month. The number of "new" food items found in each
successive scat was plotted against the number of scats analyzed. In all cases,
the curves leveled off before reaching 20 scats. For this reason, an attempt was
made to analyze between 20 and 25 scats each month to insure a representative
sample of food items was obtained.

Each scat was rinsed thoroughly in a sieve (6 sq/cm) to remove small uniden-
tifiable particles, placed in a white enamel tray and examined under a dissecting
microscope. All food items were recorded on a food habits analysis card to-
gether with an ocular estimate of the percent volume. Any food item constituting
less than an estimated 1% of the volume was considered a "trace". Data were
analyzed by percent frequency of occurrence and percent volume.

RESULTS AND DISCUSSION

Hatler (1972) concluded that scat analysis is a reliable method for determin-
ing plant and animal frequency of occurrence in the diet because most bear
foods contain some hard materials, such as seeds, cellulose, exoskeleton, and
hair that are resistant to digestion. Volumetric determinations from scats are a
valid index for most plant material, but less reliable for animal food items and
forbs. Foods which undergo a more thorough digestive process are likely to be
underestimated in volume, particularly items such as flesh, insect larvae, and
succulent forbs.

A single criterion is usually inadequate to provide meaningful results from food
habits analysis. Therefore, percent relative frequency of occurrence and percent
volume were averaged to calculate an "importance value". Importance values
for each major food type (herbaceous plants, soft mast, insects, etc.) were
graphed by month for the years 1978-1980 (Figures 2, 3, and 4) with the
intention of providing a more useful estimation of the black bear diet. The 1979
and 1980 data (Figures 3 and 4) are probably more significant because of



SEASONAL FOODS OF BLACK BEARS



135



adequate sample size. The category "other herbaceous plants" (Tables 1, 2, and
3) is a generic term used for stems and leaves other than graminoids, as well
as lichen, fungi, and cambium.



JUNE
(N = 4)


JULY
(N = I2)


AUG.
{N = I6)


SEP.
(N = 9)


OCT.
(N = I3)


25.5


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s







HERBACEOUS PLANTS



SOFT MAST



HARD MAST



INSECTS



OTHER ANIMAL



GARBAGE



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GRAMINOIDSiiiijSii^



OTHER iijiiis^^^



17 2



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FIGURE 2. Seasonal use and relative importance values of major food types determined from 54
black bear scats collected from Tahoe National Forest in 1978.



136



CALIFORNIA FISH AND CAME



MAY
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HERBACEOUS
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OTHER
ANIMAL

GARBAGE



JUN
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56 5



16 6



116



FICURE 3. Seasonal use and relative importance values of major food types determined from 170
black bear scats collected from Tahoe National Forest in 1979.



SEASONAL FOODS OF BLACK BEARS



137



MAY
(N=28)

68.6



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(N = 40)

72.0



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31



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5



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19 3



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FIGURE 4. Seasonal use and relative importance values of major food types determined from 171
black bear scats collected from Tahoe National Forest in 1980.



138



CALIFORNIA FISH AND CAME



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146 CALIFORNIA FISH AND CAME

Black bear food items were dependent on plant phenology (Tables 1, 2, and
3). Bears utilized at least 69 different kinds of plants, 6 orders of insects, and 9
genera of mammals. No attempt was made to identify birds from feather frag-
ments.

Three major dietary shifts occurred during the black bear activity period.
Herbaceous plants, mostly grasses, were the most important (importance value)
component of the bear diet from May to July (Figures 2, 3, and 4). Later,
manzanita and lesser amounts of other berries replaced green plants in the diet.
Berry consumption reached a peak between August and October. As the acorn
crop matured, it was included in the diet. Consumption of insects and other
animal food types was evenly distributed throughout the year; use of garbage
was minimal.

Herbaceous Plants

The 1979-80 spring and early summer data indicate that black bears chose
green plants, especially grasses, more than any other food type. However,
grasses generally were the only major food source available.

Importance values of forbs compared to grasses and grass-like plants (grami-
noids) must be interpreted with caution. When graminoid frequency was re-
gressed against graminoid volume an r value of .97 was obtained, while a similar
analysis for forbs produced an r value of .54. This suggests a bias, probably
associated with the higher cellulose content of graminoids resulting in more
residual undigested material in scats. Many species of delicate forbs are probably
underestimated in the diet because of low amounts of residual plant skeletal
material occuring in bear scats.

Precipitation during the winter of 1977-78 was 130% of normal and should
have resulted in more green plants for bear food, but the data (Figure 2 and
Table 1) do not agree, probably because of low sample size (N = 54).

Forbs noted most often in the analysis were bedstraw, Calium sp.; Kel loggia,
Kelloggia galiodes; lovage, and clover (Tables 1, 2, and 3). Since these same
forbs were commonly seen in the study area, a subjective judgment regarding
selective or random feeding could not be made. However, bears apparently
selected against lupine, bracken fern, corn lily, and mule ears. These plants were
also common in the study area, but seldom were found in analysis. Lupine,
bracken fern, and corn lily are poisonous to livestock.

Black bears lack a cecum and have a simple stomach too acidic to support
microorganisms capable of digesting cellulose (Rogers 1976), and therefore
have a limited ability to digest vegetation. The black bear digestive system, which
is intermediate in length between a herbivore and carnivore, probably has
evolved to allow better digestion and absorption of plant material (Herrero
1978). Graminoids and forbs are about 43% digestible compared to 73-81% for
animal food stuffs (Mealy 1975). When plant protein is a major part of the diet,
its low digestibility must be compensated by a large intake. In the Tahoe Forest
study area, scats containing herbaceous material were abundant in spring and
more easily located than any other time of year.

This period of predominantly herbaceous food consumption has been de-
scribed as the "negative foraging period" (Jonkel 1962) because bears continue
to draw on any remaining winter fat reserves in combination with a subsistence
level diet of herbaceous plants. Many other researchers have reported that



SEASONAL FOODS OF BLACK BEARS 147

weight loss also occurs during this time (Jonkel and Cowan 1971, Poelker and
Hartwell 1973, Kelleyhouse 1975). However, current research in Colorado indi-
cates that some female bears show a weight gain on a diet of green plants and
aspen buds (T. Beck, Colorado Dept. of Wildlife, pers. commun.).

In the Great Smoky Mountains National Park, the black bears' spring diet


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