Yes No Yes No - Tablelands Regional Council

TEXAS PARKS AND WILDLIFE DEPARTMENT
THE GRAY SQUIRREL IN TEXAS
BY
PHIL D. GOODRUM
Research Biologist
Cover and Drawings by Nancy McGowan
Prepared by the Information and Education Division
Published by the TEXAS PARKS AND WILDLIFE DEPARTMENT
Austin, Texas
1961
Rev. 196 1 - 1967
GFC-754-7-67-25M
ACKNOWLEDGEMENTS
Without the help of William Davis, parts of this
bulletin could not have been prepared. Special
thanks also go to W. C. Parker, whose extra help
beyond his regular duties freed the author for
field work from which came data that helped make
this publication possible.
The author received great encouragement from
H. D. Dodgen and E. T. Dawson before and during
the preparation of this booklet, and to them I extend my sincere appreciation.
Special credit should be given to the Information
and Education Division staff for its editorial comments and general supervision of handling the
technical details of publication. Photographs are by
staff photographers and the author.
FOREWORD
Many years ago gray squirrels were exceedingly common in the eastern
half of the state where virgin forests existed. Since that time, however,
gray squirrel populations in Texas have been on a steady decline. Many
forests where the gray squirrel once abounded have been subjected to
exploitation by man, the result being a reduction in habitat suitable to the
animal and significant decreases in their numbers.
Recognizing the need for a more comprehensive and detailed treatise
of the subject, P. D. Goodrum, Wildlife Research Biologist, has written
this bulletin with the idea of presenting to the public the basic fundamental
needs of the gray squirrel. It is a means by which we can better understand their steady population decline, how the habitat might be better
managed to their benefit as well as to the landowner’s, and how biologists
view the problem.
Sometimes we tend to take the obvious for granted and fail to see the
importance of its implications. Gray squirrel hunting is a prime sport in
East Texas and the steadily declining numbers of this species may someday
prove to be a great aesthetical as well as economical loss to that area.
TABLE OF CONTENTS
.........................................
‘7
...............................................
8
DESCRIPTION
RANGE
HABITAT
.............................................
9
LIFE OF THE GRAY SQUIRREL
......................
10
Description of Young . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12
B r e e d i n g
S e a s o n
How to Tell the Age of a Gray Squirrel . . . . . . . . . . . . . . . . . . . 1 2
Nest Construction and Use . . . . . . . . .
. . . . . . . . . . . . . . . . . . . 14
Temperament and Language of the Gray Squirrel . . . . . . . . . . .
15
Movement and Migration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
Predators and Competitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16
Disease and Parasites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18
Activity and Some Factors That Influence It . . . . . . . . . . . . .
19
Emasculation of Young . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19
THE CAT SQUIRREL MENU
What He Eats
20
Amount of Food Needed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22
MANAGEMENT
How Many Squirrels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23
Sex, Age, and the Crop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26
Forest Habitat Management for Squirrels . . . . . . . . . . . . . . . . . . 27
Water Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
Restocking
.........................................
30
................................
30
Hunting Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
32
Gray Squirrel Hunting
[5]
APPENDIX
BIBLIOGRAPHY
35
.
TABLE l-Food Eaten Each Month by Gray Squirrels
in Eastern Texas.
36
TABLE 2-Expected Yield of Fresh Acorns in Pounds
b y 2-Inch-Diameter C l a s s e s p e r T r e e
37
ILLUSTRATIONS
Squirrel Feeding on Pecan . . . . . . . . .
37
Illustrations of Important Squirrel Foods
Domestic Pecan . . . . . . . . . . . . . .
38
Bitterpecan . . . . . . . . . . . . . . .
38
Willow Oak Acorns . . . . . . . . . . .
39
Water Oak Acorns . . . . . . . . . . .
39
Blackgum
...
40
Sweetgum
..................
..............
40
Typical Mast-Producing Trees . . . . . . .
41
Artificial Den Box . . . . . . . . . . . . . . . .
41
SClENTIFIC
NAMES OF PLANTS AND ANIMALS USED
IN THIS BULLETIN
Plants
Animals
42
.
4
THE GRAY SQUIRREL
IN TEXAS
DESCRIPTION
The southern gray squirrel is named for its color. Those found in Texas
are usually gray on the back and sides, with whitish underparts.
Occasionally, in the northern states, gray squirrels may be black, reddish, or white-the white color phase usually suggesting an albino. However, true albinos, such as those found near Lufkin and Caddo Lake, must
have pink eyes.
“Nervous as a cat,” a phrase often used to describe the agile gray
squirrel in East Texas, helps to give it the popular common name “Cat
Squirrel.”
The gray squirrel belongs to the Order Rodentia-the gnawing mammals. Porcupines, rats, mice, beavers and the other rodents belong to the
same order. The scientific name of our cat squirrel is Sciurus carolinensis
carolinensis.
Gray squirrels average a pound in weight-about half the size of a large
East Texas fox squirrel (Sciurus niger). Its bushy tail, slightly shorter
than the body, may make it appear much larger than the average length
of 17 inches from nose tip to tip of tail would justify.
The squirrel sheds its hair twice a year-in early summer and in the
fall. The thicker fall coat serves the animal as protection from the winter
cold.
[7]
RANGE
The range of the Texas gray squirrel lies almost entirely in the eastern
portion of the state. It was known to occur in 72 counties in 1959. Hays
County appears to be the western frontier of the southern part of its range
and Fannin County is its western limit in the northern part of the state.
Formerly, it occurred farther west, particularly in the northern portion of
its range.
Vernon Bailey, in 1906, found the squirrel as far west as Jack County.
A more intensive use of the land has caused a shrinkage of the range,
resulting in a loss of good gray squirrel habitat and in fewer squirrels.
Today, the range is about three-fourths as large as it used to be.
Scattered and sparse populations are the rule in the western part of
the present range with the larger remaining concentrations found along
the lower reaches of the rivers in eastern Texas, and the hardwood forests
in the extreme southeastern section of its range.
FIG. 1. Southern Gray Squirrel Distribution in Texas
The gray squirrel is not uniformly distributed but confined to rivers and
large creek bottoms. The populations are sparse
and widely scattered in the
western part of the range. It is more abundant in the lower reachesthe
of
rivers in the southeastern part of Texas.
HABITAT
In Texas, the gray squirrel makes its home in the big hardwood
timber in the bottomlands of the rivers, large creeks, and flat lands
centering around Brazoria and Matagorda Counties. The mixed hardwood pine areas of the Big Thicket are also preferred habitats. It is
seldom found in the pine woods and upland forest. However, on occasion
it may forage a short distance into the uplands from the bottomlands.
In the northern states, the cat squirrel occurs in the uplands as well as
the bottomlands. In the early years of Texas settlement, it probably
occurred along the bottomlands of the smaller creeks, but these areas
have been logged so heavily the habitat is no longer suitable.
Optimum habitat for this squirrel is a large forested area of mature
hardwood trees with an understory of smaller trees and shrubs. Tree
stands must be dense enough to permit the squirrel to travel from tree
to tree, through the crowns, without descending to the ground. A
mixture of several species of oak,
sweetgum, blackgum, elm, red mulberry, magnolia, holly, ironwood
or hornbeam, yaupon, beech, huckleberry, pecan, hickory and some
pine provides an idea habitat. This
type of habitat is called hammock.
The presence of Spanish moss
and vines like grape, muscadine,
and rattan provide excellent escape
cover. The greater the variety of
trees, shrubs, and vines present the
better the habitat. Environments of this nature carry more squirrels than
any other type. Today it is difficult to find an ideal gray squirrel habitat
because of the poor land utilization practices applied by man.
LIFE OF THE GRAY SQUIRREL
BREEDING SEASON
Farmers and ranchmen raising livestock usually understand the breeding habits of their animals. They know what to expect in the way of a
calf or pig crop; they know when the young will be born and the influence of feeding on the yet-to-be-born. The greater the farmer’s knowledge of these matters, the better chance he has of realizing a good income
through the production of a good crop of healthy animals.
This is no less true of the gray squirrel, it being an important recreational resource and in some areas economically important. To properly
manage these animals we must first understand their needs. Breeding
habits of domestic animals are easily learned because daily observations
are made in the necessary steps of their care and feeding. Because the
wild squirrel is shy and retiring in the presence of man, a knowledge
of its breeding habits presents a more difficult problem. The animals must
be captured alive, or killed, for examination to determine when they
breed, when the young will be born and many other questions relating
to the production, growth, and welfare of the young. This job requires
specially trained personnel.
Thirty years ago little was known about the breeding habits of the cat
squirrel but in recent years much has been learned.
Although young gray squirrels may be found at any time during the
year, there are two main breeding periods-winter and summer. The
breeding season begins with the rut or mating. In winter the rut begins
about mid-December and extends into January. The peak of pregnancy
is reached in early January and the young are born in February and early
March. The summer mating period begins in late May and extends into
June. The young are born in August and September (Fig. 2). Gestation
period in the gray squirrel is 42 to 44 days, causing the peak of births to
occur about six weeks after the mating peak. Litter size varies from one to
four, averaging about 2.7 per litter. The start and intensity of the mating
period is influenced by the supply of food and the weather. Likewise, the
supply of quality food such as acorns and nuts has an important influence
on the number of young produced. A good acorn and nut crop in the fall
is usually followed by a good crop of young squirrels the next spring.
Gray squirrels prefer tree cavities for rearing their young, but in
areas where there are no hollow trees, the young may be born in specially
[10]
constructed leaf nests. Areas containing an insufficient number of den
sites produce fewer squirrels than those with dens.
More young squirrels are born during the winter breeding period
than the summer season. During the summer breeding period more
squirrels will bring forth young in leaf nests than during the winter season. Gray squirrels are very active during the rut, running after each
other through the tree tops as well as on the ground. These chases are
called the “mating chase.” Gray squirrels are polygamous; that is, each
squirrel may have more than one mate. When a female is “in season,”
several male squirrels may chase her. I have seen as many as 34 males
chasing one female. These chases are often mistaken for a migration.
During the chase there is much commotion, the males fighting each other
and all the while making a variety of noises, the most common being a
“chucking” sound.
The fact that there are two main breeding periods each year does not
mean that all female squirrels of breeding age produce two litters. It
was found in West Virginia that about one-fourth of the adult female
squirrels bear two litters a year and this same phenomenon probably
occurs in Texas.
AAY JUNE JULY AUG SEPT.
NOV.
FEB.
FIG. 2. Breeding Peaks of 235 Female Gray Squirrels in Eastern Texas
[`11]
DESCRIPTION OF YOUNG
At birth gray squirrels are helpless, having no hair or teeth, and their
eyes and ears are closed. They weigh about one-half ounce each. In
five and one-half weeks after birth the first cheek teeth appear and there
is fur on the underside of the tail. At about 14 weeks of age the young
squirrel has a full set of teeth. By this time they are independent of the
mother.
Weaning is gradual, beginning when the young squirrel is about seven
weeks old, and completed when it is about 12 weeks old. Before that time,
however, some young squirrels may leave the nest and run around in the
branches of the tree or spend brief periods on the ground. At the time of
weaning, the young squirrel weighs about seven ounces, a little less than
one-half the weight of the average adult.
Young squirrels are easy to hunt and kill, and if shot soon after weaning, one-half or more of the bag may consist of squirrels not more than
15 to 17 weeks of age. At this age they are also more vulnerable to
predators, so it is good management for the hunter to take them instead.
When a good crop of young is produced, the entire population, including
young and old, may contain 65 per cent or more young squirrels.
HOW TO TELL THE AGE OF A GRAY SQUIRREL
Tenderness of the meat and toughness of the skin are two factors most
hunters use in judging the age of a squirrel. Although these are good
indicators, there are more accurate methods for judging age. In a fully
adult male squirrel the testes are large and the scrotum is almost bare of
hair. If females show signs of having borne young, they have reached
maturity. This is determined by the presence or lack of hair around the
teats.
In skinning a squirrel, if the leg bones are tender and the joint breaks
easily, indications are that the animal is young. Measuring the weight of
a squirrel is another good way to estimate age. At 12 weeks of age it will
weigh seven or eight ounces; at 14 weeks, 11 to 11.5 ounces; at 16 weeks,
13 ounces; at 18 weeks, 14 ounces. Young animals over 16 weeks of age
often weigh more than some adults.
The best method of determining age is by the appearance of the hair
on the underside of the tail. In the juvenile or young squirrel, there is
a scarcity of hair along the fleshy part of the tail, causing it to be partially
exposed. In addition there will be two or three dark colored lateral lines
in the bushy hair along each side of the tail bone. In the adult the tail
bone is well covered with hair and there are no dark lines except on the
outer edges of the tail hair (Fig. 3).
Frequently a combination of methods will be needed to separate the
juveniles from the adults as shown in the following summary:
[12]
HOW TO AGE A SQUIRREL
Female
Adult
Juvenile
Teats easy to see-not hidden by hair.
Obviously suckling young or recently
weaned.
Teats not conspicuous-hidden by hair.
Male
Testes small. Back end of scrotum
brown, nearly free of hair. In younger
specimens it may appear that they
have no testes, but in these cases,
they have not yet descended into the
scrotum.
Back end of the scrotum is dark colored and free of hair.
Female and Male
Weight 14 ounces or less if healthy.
Hair sparse along lower fleshy part of
tail, exposing it. Two or three dark
lines on underside of tail paralleling
tail bone; tail more or less pointed.
Weight over 14 ounces. Skin tough
and thick. Joints tough, tail fully
haired and more or less rectangularshaped. No dark lines along tail, except on outside edges.
Photo by Ward Sharp, Pennsylvania Cooperative Wildlife R e s e a r c h U n i t .
FIG. 3. Gray Squirrel Tails Showing Underside
Tails 1 and 2 are from adult squirrels. Note the dark lines are obscure and
the lower part of the tail bone is covered with hair. Tail 3 is from a summer
juvenile. Note the presence of three dark lines in 3. Tail 4 is from a spring
subadult. Note the presence of two distinct dark bars. It can be seen that
the lower tail bone is exposed in 3 and 4. They are young squirrels.
[13]
NEST CONSTRUCTION AND USE
The cat squirrel has a propensity for constructing nests of leaves and
twigs. This activity begins in late spring and continues into the fall season, reaching its peak in late June and early July. Adult as well as young
squirrels take part in nest building, with each individual working on its
own nest.
The nests are used primarily as resting places and for refuge in times
of danger. In areas where tree cavities are scarce some of the nests will
be “redecorated” in late fall for winter use. These nests are strongly built
to withstand rain and wind.
The presence of many leaf nests in the fall indicates a good crop of
squirrels. Experience has shown that there will be about as many squirrels
as there are nests prior to the hunting season. In areas where hunting
pressure is heavy there will be fewer squirrels than nests as the hunting
season progresses. In late spring female squirrels often move their suckling
brood from tree dens to leaf nests, carrying the young by the nape of the
neck in the manner of a house cat. This is done to take advantage of the
cooler quarters provided by the nests.
TEMPERAMENT AND LANGUAGE OF THE GRAY SQUIRREL
Cat squirrels are notably gregarious, being found in considerable numbers in favored localities. Perhaps this habit is useful in defending its
home against the bigger and more pugnacious fox squirrel. I once witnessed a fight between one fox squirrel and three grays. The attack by
the three grays put their opponent to flight. In a “man-to-man” fight the
fox squirrel would have won the battle.
The gray squirrel is nervous and easily frightened. When disturbed,
it will move readily from its hiding place. Hunters have learned to take
advantage of this trait by shaking vines and bushes to make the “bushy
tail” show himself. Once routed from its hiding place, it will run with
great speed through the tree branches or jump directly to the ground in
its effort to escape. The hair on the tail will stand on end once it has been
frightened, giving it a bushy appearance.
This flaring of the tail has a useful purpose in that it acts as a sort
of rudder, helping the squirrel to keep its balance in its race through the
tree tops. A squirrel with little hair on its tail will often fall from a tree
when it tries to run.
The cat squirrel is normally a noisy animal. When the woods are quiet
and undisturbed they are continually barking. Apparently this is reassuring to all animals in hearing distance of each other and signals that all
is well. When one is disturbed it emits a warning “bark,” a signal for the
others to remain quiet. If further disturbed they immediately seek a
hiding place. Most of the barking takes place while the animal is in the
tree, little being done while on the ground.
The most common voice is a c-h-u-c-k c-h-u-c-k c-h-u-c-k repeated
rapidly and followed by a heavy buzz, and often interpolated with a grunt.
It is a kind of muffled bark, and is commonly referred to as “barking.”
During the mating season squirrels are particularly noisy. At this time,
part of the barking assumes more of a musical quality, being higher
pitched. It is a sort of song, with a loud quack-quack-quack-quaaaaaaa,
quack-quack-quack quaaaaaaa. The latter part of the series is a highpitched whine.
MOVEMENT
AND
MIGRATION
Although cat squirrels are rather mobile during spring and fall, particularly in the fall, they do not roam far from their headquarters or
home tree in late summer or winter. It has been noted that greater movement or travel takes place following the two main breeding seasons, spring
and fall. A great deal can be learned about the movement of squirrels by
trapping them alive and marking them. In this way it has been learned
that squirrels usually live out their lives in a comparatively small area,
the center of which is the “home tree” or headquarters. The individual
squirrel’s home territory is about two acres, although at times it may
venture as far as 200 yards from the home tree.
[15]
The abundance and availability of food are the most important factors
influencing the movement of squirrels. During a period of food scarcity,
especially when the squirrel population is high, they might move four or
five miles in search of food. This phenomenon has led many persons to
believe that the gray squirrel is migratory. Migration implies that an
animal spends part of a year in one place and another part in another
place. A one-way trip cannot be regarded as a migration. From written
records it appears that mass movements of the gray squirrel were formerly
more common than they are at present.
A mass movement of the eastern gray squirrel was witnessed in Connecticut and New York in 1933. This mass movement, according to
George C. Goodwin’s writing in Nature Magazine, covered the entire
state of Connecticut. The squirrels moved from Connecticut toward and
into the state of New York, crossing several major streams en route. Upon
reaching New Jersey many of them disappeared. Numerous dead squirrels
were seen along the travel route and it seems likely that most of them died
before reaching New York.
D. L. Allen, in his book, Michigan Fox Squirrel Management, describes a mass movement or “migration” that took place following a fantastic overpopulation in Michigan. Allen, quoting Norman A. Wood, said,
“ ‘J. Austin Scott witnessed a migration in the fall of 1840, when hundreds
of gray and black squirrels (some gray squirrels are black in Michigan)
crossed the Raisin River near Adrain. They came from the south and
were so exhausted from swimming across the river that the boys killed
many with clubs. He counted 30 in one small tree near the water’s edge’.”
I have never witnessed nor heard of such a movement in Texas. However, such mass movements
may have taken place in past years, but none
have been recorded. Mass movement of squirrels usually follows an abnormal increase in number, a drastic shortage of food or both. The present
population decline, coupled with habitat destruction and deterioration,
indicates that mass movements in the immediate future are unlikely.
PREDATORS AND COMPETITORS
The casual observer of cat squirrels in the wild gets the impression that
the “bushy tails” lead a carefree existence, except when hunted by man.
This is far from the truth. Even when not hunted, the squirrel is threatened
from all sides. The threat is primarily a two-sided one-from predators
as well as competitors. Squirrels, however, are no different from other
wild animals in this regard. In the wild, all animals must fight to survive.
Squirrels are preyed upon by a number of animals such- as bobcats,
red shouldered hawks, minks, raccoons, domestic cats, Cooper’s hawks,
gray foxes, owls (especially barred and great horned owls), and snakes.
The rattlesnake and chicken snake are known to catch and devour squirrels.
[16]
Predation is seldom witnessed. However, I once saw a red shouldered
hawk catch a gray squirrel. Also, on one occasion I came upon a five-foot
canebrake rattler that had an adult squirrel half swallowed.
A given habitat is limited in the number of squirrels it will support, and
the number taken by predators is greatly influenced by the abundance of
g o o d food and cover.
The cat squirrel has many competitors for food and shelter. Den sites
in the woods are always in great demand. Not only are they used by
squirrels but often by a number of other animals such as woodpeckers,
honey bees, flickers, wood ducks, flying squirrels and other hole nesting
animals.
They must share their food supply with other animals and there is
seldom enough to go around. This is especially true of acorns and nuts.
Deer, turkey, woodpeckers, flickers, crows, bluejays, flying squirrels, fox
squirrels, domestic livestock and many others compete for the food supply.
When there is an abundance of food they all are well fed, but when nuts
and acorns are scarce it is the squirrels that suffer most because they rely
on them nearly all year.
DISEASE AND PARASITES
Like most wild animals, cat squirrels are subject to disease. In my
opinion, those in Texas are largely free of disease, but on rare occasions
disease may seriously reduce them in number. Squirrels have been found
dead in the woods, but seldom has the killing agent been identified.
E. C. Bertram reported finding 13 dead squirrels in the woods in
Kentucky and determined that they died of coccidiosis coupled with
malnutrition.
A parasite commonly found in the squirrel is mange. It is associated
with the scabies mite which burrows into the skin and causes the hair
to fall out. A scab then forms. This affliction appears to occur where there
is an overpopulation of squirrels and a scarcity of food.
The chigger or redbug is one of the most serious external parasites
of the squirrel in Texas. Fully 75 per cent of all squirrels killed during
the summer are infested with them. I have seen them so heavily infested
that the animals were in an emaciated condition. Squirrels so infested
just prior to the breeding season are in no condition to produce young.
The flea is another common pest of squirrels. Few fleas are found on
squirrels in summer, but in winter they are quite numerous, especially
on nursing females.
Another parasite of the gray squirrel is the larvae of the botfly, often
called “warbles” by the hunter. The larvae are embedded in the skin.
We have no evidence that they cause death of the host.
ACTIVITY AND SOME FACTORS THAT INFLUENCE IT
The cat squirrel is an early riser. At the break of day, and frequently
earlier, he has emerged from his night quarters and is busy searching for
food. However, if the temperature is low-that is, about freezing, --he will
remain in bed until things warm up a bit. Likewise, if there is a stiff
wind, his activity is reduced to a minimum, for there is nothing he dislikes more. Warm gentle breezes do not deter him. Only if the wind is
strong enough to move small branches is it a signal for him to seek shelter.
During high wind it is more difficult to detect danger and to jump from
branch to branch.
Although the gray squirrel has keen ears and eyes, these senses do not
function well during windy weather. Prolonged cold, accompained by
wind, nearly stops squirrel activity. If the weather is especially bad he
will remain under cover all day, and if it continues cold, windy and wet
for several days the squirrels may go into a state of lethargy and remain
inside until the bad weather abates.
Gray squirrels are comparatively inactive through the middle of the
day, preferring the early morning and late afternoon hours for feeding.
Some activity, though on a reduced scale, may occur throughout the day
during the rutting period.
The abundance of food has great influence on squirrel activity. If food
is abundant it does not take long for them to satisfy their appetites and
retire to their resting places. On the contrary, if food is scarce they are
abroad for longer periods.
The texture and condition of the soil has much to do with local abundance and activity. Squirrels spend more time on the ground than is commonly supposed. They prefer to search for food in soft soils, and when
the heavier soils are dry they will shun them until rain comes to soften
the ground. Contrary to popular belief, gray squirrels do not cache or
store food in the holes of trees for future use, but they spend much time
burying it in the ground.
The cat squirrel’s habitat is usually well watered, but during droughts
water may be an important factor influencing its activity. During normal
times, they will be evenly distributed over the habitat, but during the
d ry periods they will be found concentrated around streams, ponds, and
lakes. Environmental conditions around bodies of water favor the production of tender buds on which the squirrels feed.
EMASCULATION
OF
YOUNG
It is a widespread belief that old male cat squirrels and fox squirrels
castrate or emasculate young male gray squirrels. I have examined hundreds of young male squirrels and have seen no evidence to support this.
This misconception stems from the fact that the testicles of squirrels do
not descend into the scrotum until the animals are sexually mature. The
undeveloped scrotum of the young squirrel has a sparsity of hair making it
[19]
appear as a scar resulting from castration. Occasionally an adult gray male
squirrel may appear to be without testicles. This is due to the fact that
males often retract the testicles into the body cavity after the breeding
season.
It is possible for the botfly larvae or “grubs” to destroy the testes of a
squirrel, but this rarely occurs. This misconception is not confined to
Texas. In the middle west, the red squirrel is accused of castrating the
young cat squirrel.
THE CAT SQUIRREL MENU
WHAT HE EATS
The primary aim in life of the cat squirrel is to get plenty to eat. In
this regard he is no different from other animals, wild or domestic. A good
portion of his active hours, which may be before or after daylight, is
spent in this most important endeavor. In the view of importance of food
in the life and welfare of the gray squirrel it behooves us to learn all we
can about his food habits.
The gray squirrel eats a great variety of wild foods but he has a special
liking for acorns and nuts.
It is, therefore, not surprising to find the cat squirrel largely confined
to our hardwood forests. Much has been learned about the feeding habits
of the gray squirrel through observation under natural conditions. However, to get a better understanding of their feeding habits, it is necessary
to study the contents of the stomachs. Even by using both methods to
determine the menu we would fall short of the learning of everything
that was eaten. Too, certain foods may be available during one season
or one year, and not available at a different time.
The analyses of 125 stomachs covering each month of the year for a
two-year period and weekly observations throughout the year have given
us good information on what foods are eaten. Stomach analyses alone
showed that acorns accounted for 59 per cent of the diet. Furthermore,
acorns were eaten during every month of the year with the greatest amount
being consumed in the fall and early winter (Table 1).
During this period the squirrels also bury acorns and nuts. During a
normal year, acorns and nuts are scarce on the surface of the ground by
the end of January. After that time, squirrels dig up the acorns previously
buried or covered by leaves. They do not get them all. Many are left in
the ground to sprout and produce seedlings which may eventually grow
into trees.
Pecans are preferred to acorns, but acorns are usually more plentiful.
The most important mast-bearing trees in the habitat of the cat squirrel
are the willow oak, water oak, overcup oak, white oak, cow oak, blackgum, sweetgum, tupelo gum, shagbark hickory, pecan, beech, magnolia,
hornbeam, pine, and swamp red oak.
During early spring the cat squirrel supplements the mast diet with
buds, tender stems, and flowers of a variety of trees and shrubs, including the oaks, hawthorn, hornbeam, elm and hackberry. Animal matter
in the form of larvae of many insects is also taken. Mushrooms are relished
and they are fed upon avidly during periods of wet weather when they
sprout from the damp soil and rotten logs. Red mulberry and maple seeds
are choice foods in the spring. As many as a dozen squirrels have been
seen in a single mulberry tree feeding on its fruit.
During most of the summer, oak mast continues to be the main item
in the diet, but other foods are taken in substantial amounts. Grapes,
berries of rattan, wild plum, blackberries, blackhaw, grass seed, and insect
larvae are eaten. In late summer squirrels begin to eat acorns, pine seed,
hickory, pecan and sweetgum while still green or in the dough stage.
Squirrels supplement their diet with different kinds of bone, including
the antlers of deer. The latter seem to be preferred. Antlers do not last
long after they have fallen from the buck deer in the early spring. Not
only do the squirrels feed upon them, but so do other rodents. Bones and
antlers apparently supply the squirrels with needed calcium.
Although acorns and nuts comprise the majority of items on the menu
in fall and early winter, squirrels consume small quantities of a great
variety of other mast foods such as seeds of the palmetto, weeds, hawthorn,
turkey berry, yaupon, dogwood, blackhaw, maple, rattan, and hop-hornbeam. Squirrels also eat frogs and lizards.
Experience with caged squirrels indicates a need for animal food.
Squirrels that receive no animal food usually do not bear young. The per
cent animal matter in the diet of wild squirrels is only about 4 per cent,
mostly insects.
[21]
From the great variety of food taken by the gray squirrel, we may
conclude that an ideal habitat would contain numerous plant species,
from the bigger trees to the smallest herbs. The borders of bottomland
forests are richer in plant species than the unbroken forests and we frequently find squirrels concentrated there.
AMOUNT OF FOOD NEEDED
A squirrel should have food each of the 365 days of the year, but he
seldom gets enough of it every day. He can skip a meal or two without
much harm provided he is in good shape beforehand. For example, during periods of inclement weather he may elect to miss a few meals if he
is well fed, but if in poor condition he may be forced to go abroad in
search of food. The usual bountiful supply of mast in the fall and early
winter enables the squirrel to put on a thick layer of fat. His hair is
sleek when his stomach is full. In the search for buried acorns and nuts
the squirrel hops over the ground sniffing and when he begins to dig he
nearly always finds what he is looking for.
To fare well, an adult gray squirrel must have about two-tenths of one
pound of food per day on a fresh weight basis. Furthermore, this food
must be nutritious. Acorns and nuts are high in carbohydrates and fats.
Pecans, hickory nuts, and walnuts are particularly high in fat content.
So are the acorns of certain oak trees. In considering the food need of
squirrels it is helpful if we understand the productive capacity of the mast
bearing trees, particularly the oaks since they provide the mainstay food.
We have learned through research that the bulk of acorns are produced
by the bigger trees. Most bottomland oaks do not produce seed until they
reach 10 inches in diameter at breast height. In some situations even
trees of this size do not produce. Trees that are too crowded are forced
into this category. The reason for this is that such trees do not develop
good crowns and a tree without a good crown produces little mast. The
bigger the tree the more mast it will produce, but there are exceptions.
Many of the bigger trees are in a state of decadence and, therefore, unable to produce many seed. However, a hollow trunk does not necessarily
affect its fruiting ability. Thrifty trees normally bear a good crop of mast
every third year. The reasons for this are not clearly understood. We do
know that late frosts kill the flowers, thus preventing seed formation. In
an average year we can expect only about 13 pounds of fresh acorns from
an 18-inch tree.
Now let us see how many 18-inch oaks it will take on each acre
to feed one squirrel for ten months or 300 days. Let us be conservative and assume that the daily take of food consists of only three-fourths
acorns. Since it requires two-tenths of one pound to feed one squirrel
and we assume that 75 per cent of this is acorns, then the amount of
fresh acorns needed will be 0.15 pounds daily, and 45 pounds for 300 days.
[22]
Let us further assume that we have had an excellent crop of squirrels
and the population density is about two to the acre. Then, 90 pounds of
acorns would be required to feed two squirrels for 300 days. We know
about what to expect in acorn yields from the average productive year
for several kinds of oaks (Table 2). We know that we rarely have a
good crop of acorns on all species of oaks present in a habitat. So let us
assume again that we have four kinds of oak in our habitat, but only
two of these, water oak and red oak, had a normal or average crop of
acorns. The others failed completely. By using Table 2 we find that each
18-inch water and red oak will produce 13.31 and 6.15 pounds of acorns
respectively. Since we must have about 90 pounds of acorns we can see
that we shall need about 7 water oaks and 15 red oaks of this size on
each acre. In most habitats we have several oak species of various sizes,
SO the number of producing trees needed will vary, depending on the size
and kinds of oaks present.
The problem does not end here if we expect to arrive at how many
trees are needed to produce the required pounds of acorns. Squirrels
are not the only animals that consume acorns. Throughout the United
States 185 kinds of wildlife are known to eat acorns. In East Texas, deer,
wild turkey, fox squirrel, bobwhite quail, raccoon, opossum, woodpeckers,
flickers, bluejays, flying squirrels, crows, rats, and mice also compete
with the gray squirrel for acorns. Frequently, woods-roaming hogs take
heavy toll of the mast. In addition, about one-fourth of all acorns produced
will be ruined by the acorn weevil.
Therefore, we must produce about 112.5 pounds of acorns to get 90
pounds of sound nuts to feed two squirrels for 300 days. This will require about 8 water oaks and 18 red oaks on each acre. In view of all
the things that affect the amount of acorns available, we may reason that
squirrels seldom have enough to keep them in good condition at all times.
When we consider all of the adverse factors working against the gray
squirrel we can readily see that the forest must be kept in top condition
to favor mast production, for the secret of more squirrels is more mast
food.
MANAGEMENT
HOW MANY SQUIRRELS
How many squirrels? This is an all-consuming question to wildlife
managers charged with the responsibility of recommending open hunting
seasons and bag limits. Furthermore, the number of squirrels present
indicates the condition of the habitat and this in turn may suggest a
need for habitat improvement. A “lot” of squirrels may mean one thing
to one hunter and quite another thing to some other hunter. The first,
for example, may think that one squirrel to the acre is “scarce” while
the second may visualize that as “plentiful.” We can see, therefore, that
[23]
there is no standard of abundance among the rank and file of squirrel
hunters. It is an axiom among wildlife managers that some standard of
squirrel abundance be accepted by all. It is common practice among them
to express abundance in terms of animals per acre or acres per animal.
The amount of land that a squirrel uses depends upon the land location
and its quality. “Quality” may be described as the amount of good food
available, presence of den trees, escape cover in the form of tree hollows,
vine tangles, and tree stand density. But the problem does not end here.
Some wild animals can be crowded into a given area more than others
and get along all right. This phenomenon may be called “tolerance.” Anyway, wildlife managers have come to judge carrying capacity by the
number of wild animals found on a given unit of land under different
conditions. The range in the number of animals per acre may be high
or may be low, depending upon the suitability of the habitat, other factors
being equal. Wildlife managers now have a good idea of what is meant
by high populations and low populations amongst most game animals.
Studies in several places in the United States have established the fact
that optimum habitat can carry, on the average, about two gray squirrels
per acre. This population density may be considered “plentiful,” while
one squirrel to six acres may be considered “scarce.” One cat squirrel per
acre may be considered “a lot.” Certainly this density would provide
good hunting, which means that a hunter would have a comparatively
easy time getting his limit of squirrels. There may be times when a
large number of squirrels may congregate in a restricted area because of
a temporary abundance of choice food. Under these conditions we may
find as many as 10 squirrels per acre for a limited scope of woods over
a short period. But when the food plays out the squirrels disperse to their
usual niche in the forest.
There are several methods that have been used by game managers
to determine the density of squirrels. None of them are exact, but some
are reliable in estimating the population. The job of finding out how
many squirrels there are in the woods is called a census. The most accurate
method is the “trap census.” The animals are trapped alive, marked, and
then retrapped. In this way, the squirrels are counted on a given acreage
of land. But the practicing wildlife manager does not have sufficient time
to devote to trapping and tagging, so there are other methods that suit
him better. Furthermore, the manager is more interested in whether he
has more or fewer squirrels on a given area. The wildlife research worker
tries to get an exact count of the number of squirrels and thus establish
the carrying capacity of various habitats. What the managers want to
know are the “indicators” of increase or decrease, or the trend in the
number of squirrels. A method widely used, developed by the author, and
used by game managers and researchers, is the “time-area” count. The
observer seats himself in the woods and remains quiet for a given period
of time, at least 25 minutes, to give all the squirrels time to “loosen up”
or show themselves. All squirrels seen are counted and the area of
[24]
visibility measured. Several counts are made in the area to be censused.
This method is also time consuming. For the wildlife manager a practical
way of determining trends is to use a combination of methods. First, make
a “time-area” census, and second, count all the leaf nests on a given acreage and then establish a ratio of the number of squirrels to the number
of nests. Each year thereafter only the nests need be counted. This will
give trends in the population. Before the hunting season begins there
normally is one nest to one cat squirrel, but this varies according to the
type of habitat and the number of suitable den trees available. “Timearea” censuses may be made at any time of year, but if the leaf nest
method is to be used in conjunction with it, it must be made in the fall
as close to the opening of the hunting season as possible to give more
time for the leaves to fall from the trees so that the nests may be easier
to locate.
A typical leaf nest constructed by the gray squirrel. Nests of this nature are
the type the wildlife managers count while conducting the gray squirrel
population census.
Many factors influence the abundance of gray squirrels. Food is the
most important. When food is plentiful during the fall preceding the winter
breeding season, a good crop is usually produced, resulting in a high population. However, this does not always occur. If the population is extremely
low before the onset of the breeding season, there will not be a high population. It sometimes happens that a “crowded” population may be present
just before the breeding season. Under this condition the animals are
subject to disease and greater predation, even though there appeared to be
enough food and cover.
When squirrel numbers greatly exceed the carrying capacity of an area,
they may move out, searching for food. When this happens they are
especially vulnerable to predation because squirrels on the move are not
familiar with the escape cover, and thus lose their lives. This is nature’s
way of bringing things into balance.
[25]
SEX, AGE, AND THE CROP
A population of gray squirrels at birth is comprised equally of females
and males, but it may not remain this way. In West Virginia, it was found
that adult females outnumbered the adult males. Many counties in Texas
have an open season on squirrels during the brooding period. At this time
the females with young in the nest are seclusive while the males remain
active. This may result in a greater mortality of males, thus leaving more
females in the woods than males.
Game managers are constantly trying to determine the size of a
young crop of game animals of whatever kind, including squirrels. This
information is of vital importance, for if this data is in hand he can recommend proper open hunting seasons and bag limits. Bag limits can be
increased when there is a big crop of young and reduced when few are
produced.
We know that when a population contains a high percentage of young,
squirrels will be more plentiful and the population is on the upswing. The
per cent of juveniles in a spring population varies from 50 to 75. If numbers are on the upswing, the population usually is composed of 60 per cent
or more of juveniles. If the population is decreasing it usually contains less
than 55 per cent juveniles.
This information can be collected before the opening of the hunting season by live trapping and tagging. It also may be obtained by killing some
of the animals for study before the season opens.
Squirrels in the wild are subject to high mortality. Nature intended for
it to be this way. Since young squirrels make up about 60 per cent of a
given yearly population, it follows that a great many of them lose their
lives by the time they reach their first birthday, because young squirrels
have not yet learned how to protect themselves.
[26]
FOREST HABITAT MANAGEMENT FOR SQUIRRELS
The manner in which a forest is managed has a dynamic effect upon
the gray squirrel. Haphazard methods of harvesting hardwood timber
have never been favorable to squirrels, for the best trees are usually cut,
leaving the culls and a poorer home for them. Most of our bottomland
forests have been cut over several times and after each cutting it was
made less favorable to the squirrels than before. This deterioration of
the habitat not only has seriously reduced the supply of food but has
destroyed too many den trees.
Slashing of the forests has left many tree stands so thin that they no
longer meet the requirements of the gray squirrel. An open type forest
is more suitable to fox squirrel and they have invaded the altered bottomland woods. We have always had a few fox squirrels in the bottomland
forests, but in the virgin forests the gray squirrel usually predominated.
More and more fox squirrels are found in the thinned woods. If the woods
are to be kept suitable for the gray, they must be managed properly. This
means that a good stand of big trees must be maintained, including an
adequate number of den trees. Sweet gum and bald cypress have more
holes in the trunk and limbs than most kinds of trees and large specimens
of these should be favored.
The middle-aged trees are the most valuable for squirrels because they
furnish the most food and good brood rearing sites, as well as opportunities
for play and exercise. These trees are at the height of their seed production and, therefore, are important from the standpoint of forest maintenance.
Left: Typical den site once inhabited by family of gray squirrels. Due to
haphazard methods in harvesting hardwoods, this forest has become so thin
it is no longer suitable for the gray squirrel. Typical area in which fox
squirrels become resident. Right: Typical den site now inhabited by family
of gray squirrels. Note vines and heavy cover.
[27]
To further favor squirrels in timber management work, care should
be taken to leave an adequate number of the so-called “weed” species, such
as hornbeam, elm, postoak, magnolia, grape, rattan, hop-hornbeam, pecan,
and other species usually considered a drug on the commercial market, but
valuable to squirrels.
The clearing of bottomlands for crops and pastures has resulted in a
great loss of squirrel habitat. Recently, more bottomland forests have been
cleared for pastures than for crop land. For a period of 40 years there has
been a gradual and steady increase in the use of bottomlands for livestock
range. Inevitably overstocking has brought on overgrazing with an attendant deterioration of the squirrel’s home as well as the forest. It prevents
the growth of seedling forest trees, shrubs, and vines.
Most bottomland hardwood trees, shrubs, and vines are relished by livestock. As a consequence, we do not have enough young trees to replace
those harvested. The vines, especially grape and rattan, we see in the woods
today are usually old specimens. There is little reproduction to take their
place. Red mulberry and ash have been practically banished from many
bottomlands by grazing livestock.
In some areas hogs in the woods are serious competitors for the mast
supply. These animals have no place in a well managed habitat.
Since water areas are necessary ingredients of an ideal gray squirrel
habitat, drainage would naturally lead to a reduction in the number
of squirrels. Squirrel populations have been studied on areas before and
after drainage. A marked reduction in number of animals occurred after
drainage. Drainage reduces not only the water supply but food as well.
Important acorn and nut producing trees are dependent upon wet areas.
The present demand for large lakes or impoundments will eventually remove more gray squirrel habitat from the range.
When an adequate number of den
trees are lacking, artificial den boxes
may be installed in the larger trees, 20
to 30 feet up from the ground. They
should be 10 to 12 inches wide and 14
to 16 inches long. Rot-resistant lumber,
like cypress, should be used. Make the
entrance hole 2 to 3 inches in diameter
and near the top of the box. Erect the
box so the hole will be next to the limb
or trunk. Nail kegs may be used instead
of boxes.
Artificial boxes, like natural tree
holes, are often used by other animals,
especially flying squirrels and woodpeckers. Frequently they will be taken
over by bees and wasps. This means
that more boxes than actually needed
[28]
Artificial den box made from hollow log. This type den box should be used
when possible because of the natural appearance.
must be erected. To facilitate cleaning every two or three years, the boxes
may have a hinged bottom. Flying squirrels have a habit of filling a cavity
with nut and acorn shells and other debris. The cat squirrel, on the other
hand, is a clean housekeeper. Nothing will be found in their dens except
leaves and finely shredded material as a lining for the nest.
Some of our squirrel woods today contain excessively dense stands of
young oaks, sweetgum and other species of trees. In these dense stands
the trees grow slowly and develop poor crowns. It is good forest management to thin these stands so that better quality timber may be produced.
Too, a tree with more growing room will make a better mast producer.
In former years our hardwood forest contained an adequate number
of vines, but overgrazing by livestock has prevented the growth of young
vines to replace the older ones that have died. Exclusion of livestock for
two years and light to moderate grazing thereafter would encourage vine
growth and thus provide a source of food and cover. Where vines are
lacking they should be planted. Grape and rattan, both of which occur
naturally in the gray squirrel range, are the best to plant.
Hogs and livestock have also prevented the growth of oak and other
nut tree seedlings.
[29]
WATER
SUPPLY
Gray squirrels can go long periods without drinking water, but when
it is available they use it. In Texas, this squirrel is found only in well
watered areas. A well watered area is favorable to the growth of vegetation
preferred by the squirrels. In such areas they get all the water they need
from the vegetable foods eaten. Periodically all of eastern Texas is subjected to droughts. During these dry periods the squirrels suffer.
To overcome this shortage of water during droughts, ponds may be
created by throwing up narrow earthen dikes along the sloughs, creeks
and flats. Water can often be held in the flats by throwing up a dike with
an ordinary turning plow.
Drainage projects should be undertaken only after careful study has
shown that squirrels will not be adversely affected.
RESTOCKING
It is popular to think of game management in terms of restocking. Yet
very little lasting benefit comes from this activity. As far as the cat squirrel
is concerned I do not know of any wild area that has been restocked.
However, gray squirrels have been successfully stocked in several city
parks in Texas.
These successful plantings suggest that the cat squirrel could be successfully stocked in a suitable area under wild conditions. However, if
only a few animals remain in an area, the release of additional squirrels
probably would not result in more squirrels. The fact that an area has
only a few squirrels indicates that the habitat is not suitable and that to
have more squirrels it would be necessary to correct the deficiency in the
environment.
GRAY SQUIRREL HUNTING
Within its range in Texas, the cat squirrel is the most important game
animal, with the possible exception of the fox squirrel, from the standpoint of the number of persons hunting it. We do not have exact figures
on the number of hunting license holders that hunt squirrels in Texas, but
in the adjoining state of Louisiana more than 62 per cent of the license
holders hunt squirrels. These hunters went out after squirrels an average
of seven times each during the open season and the average number of
squirrels killed was two each. From these figures it was estimated that
1,901,294 squirrels were killed during the hunting season.
In the state of Mississippi, about 80 per cent of all license holders hunt
squirrels. On the basis of these data I believe that we may safely estimate
that from 60 to 75 per cent of the hunting license holders within the cat
squirrel country in Texas hunt squirrels.
[30]
A person squirrel hunting will take any kind of squirrel, but a survey
of hunters in East Texas indicated a majority preferred the cat squirrel
over the fox squirrel. There is no doubt that the flesh of the cat squirrel
is more palatable than the fox squirrel. Furthermore, the sporting qualities
of the gray are superior to the fox. When the gray is routed from his
hiding place he will run through the tree tops, forcing the hunter to make
a running shot or lose his chance at getting the squirrel.
The fox squirrel, on the other hand, is loathe to run but will skillfully
hide himself in the tree. He does his best to keep a limb between himself
and the hunter by turning on the limb as the hunter moves around looking
for him.
A sporting shot for any hunter. It would take a sharp, quick trigger finger
to bag this bushy tail. Given a couple more seconds, he will be in the protec.
tion of heavy cover and will be difficult to locate
The method of hunting and attitude of the hunter determine the value
of the quarry. There are many different ways to kill a squirrel and some
of them play an important part in the management and welfare of gray
squirrels. Some hunters are after meat and some hunt for recreation. I
have records to show that in the year 1924, a party of four hunters killed
more than 100 cat squirrels in the Big Thicket area of Texas in less than
one day. This could hardly be called sport hunting. Perhaps the participants
got some pleasure from the shooting, but certainly it was not an exhibition
of sportsmanship as we know it today.
I know squirrel hunters who get as much or more pleasure from killing
only two or three squirrels. Although they do not often express it, such
hunters are greatly exhilarated and refreshed by just being out in the
woods and matching wits with the squirrels. The sight of a spider spinning
[31]
his web in the early morning or a deer stealing by is all a part of the
show and takes one’s mind off the worries of office or home.
“Still hunting” is perhaps the most common way of hunting squirrels.
The word “still” suggests the manner in which this type of hunting is
done. One cannot find many squirrels by blundering through the woods.
Squirrels are acutely sensitive to sound and a man walking briskly through
the forest has little chance of seeing them. “Still hunting” assumes two
forms-sitting still or walking slowly and quietly.
The most productive form of still hunting is to find a likely spot for
squirrels as indicated by “cuttings” of nuts and twigs or by the number
of leaf nests present. After locating the squirrel “sign” one must remain
perfectly quiet for at least 20 minutes or longer. It is best not to shoot the
first squirrel that shows himself, for to do so would cause others nearby to
remain hidden. On the other hand if the first squirrel is permitted to move
around unmolested it will encourage others to move about.
Unlike the fox squirrel, the gray squirrel is often found in groups---so
where you find one, others are likely to be nearby.
The cat squirrel is frequently hunted with dogs. A good dog must he
experienced in the ways of the cat squirrel. This squirrel frequently does
not remain in the tree in which he first took refuge. It may run through
the branches of several trees before deciding to hide. A good dog is one
that has learned to observe the squirrel running through the tree tops until
it stops. Once hidden it will remain so until the hunter appears. If it has
a good hiding place it may be difficult to locate, especially if the hunter
is alone.
There is a definite advantage for two persons to be together on a hunt.
One hunter can move to the opposite side of a tree to “turn” the squirrel
while the other remains quiet. To make a squirrel move to the other side
of a limb it is often necessary to shake a bush or vine. Vine shaking often
puts the squirrel to flight, making it necessary to shoot the animal on the
run-a sporting way to hunt.
When two or three persons are hunting together, they may go through
the woods pulling vines to move the game from its hiding place. This type
of hunting does not require sitting still, but moving from one vine-covered
tree to another. This kind of hunting is dependent upon a plentiful supply
of vines.
HUNTING REGULATIONS
Hunting regulations in 1959 in the 72 counties in which cat squirrels
occur were far from uniform and most county laws permitted hunting
during parts of the breeding seasons (Fig. 4).
In 1959 there were 13 different laws that governed hunting seasons
and 7 that restricted the bag limit. Six counties had no closed season
while 40 more came under the provisions of the general squirrel law
permitting hunting for six months, May, June and July and October,
November, and December.
[32]
Fourteen counties had no restriction on the bag. Ten other counties
had special laws limiting the daily, weekly and possession limits. State
laws, designed to limit the number of squirrels killed, vary greatly. The
general state law permits a bag of 10 daily with a possession limit of 20
and most of our counties come under this provision. Four counties now
permit a daily bag of five squirrels, whereas 20 years ago only one county
limited the daily bag to five. Surveys in other states, where the cat squirrel
is more abundant than in Texas, have shown that hunters seldom achieve
a bag of five squirrels in a day’s hunt. In Louisiana, one of our nearest
neighbors, 5,868 hunters showed an average kill of 1.9 squirrels per hunter
per day. In West Virginia only about 7 per cent of 20,271 hunters got
the daily bag limit of four squirrels. This multiplicity of laws suggests a
need for revision to obtain more uniform regulations.
Although habitat destruction and deterioration are the major causes of
the declining cat squirrel population, overhunting has been harmful in
many localities. As of 1959, three Texas counties-Jasper, Newton, and
Tyler-had laws that permitted hunting only when breeding activity was
at its lowest ebb. Some cat squirrels may be born during any month of
the year, but the lowest points of breeding activity come during the periods
of May 15 to June 15 and October 15 to December 10 each year. Squirrel
populations might increase if hunting were permitted only during these
periods. Of course, there are other factors to be considered in setting
hunting seasons other than the breeding periods. In a few localities,
especially in the southwestern portions of the range, gray squirrels may
damage pecan or grain crops, requiring special regulations in these places
to reduce damage. But in most of the gray squirrel range there is little
crop damage from these animals. Recent land use practices involving
changes from crops to livestock range and forests have greatly lessened
the possibility of crop losses from squirrel depredations. However, hunting
to reduce crop damage is only a temporary measure. Damage may be
avoided in pecan orchards by placing tin or aluminum shields around the
trees.
BIBLIOGRAPHY
Allen, John M. 1952. Gray and fox squirrel management in Indiana.
Indiana Department of Conservation, Indianapolis, Indiana.
Allen, Durward L. 1943, Michigan fox squirrel management. Michigan
Department of Conservation, Lansing, Michigan.
Coulter, Malcolm W. and Clarence E. Faulkner. 1959. Small mammals
of Maine. Bulletin 475, Maine Extension Service, Orono, Maine.
Goodrum, Phil D. 1940. A population study of the gray squirrel in eastern
Texas. Texas Agricultural Experiment Station, College Station, Texas.
Goodrum, Phil D. 1959. Acorns in the diet of wildlife. Proceedings, Southeastern Association Game and Fish Commissioner.
Hankla, Donald. 1956. The gray squirrel. Wildlife in North Carolina.
North Carolina Wildlife Resources Commission, Raleigh, North Carolina.
Kidd, J. B. 1955. Squirrel research. Louisiana Conservationist, November
1955. Louisiana Wildlife and Fisheries Commission, New Orleans, La.
Sharp, Ward W. 1958. Ageing gray squirrels by the use of tail-pelage
characteristics. Journal of Wildlife Management, Vol. 22, No. 1.
Seton, E. T. 1929. Lives of game animals. 4 (Part I) : 9-58. Doubleday,
Doran & Co.
Texas Game, Fish and Oyster Commission. 1945. Principal game birds
and mammals of Texas. Texas Game and Fish Commission, Austin,
Texas.
Uhlig, Hans G. 1956. The gray squirrel in West Virginia. The Conservation Commission of West ‘Virginia, Charleston, West Virginia.
[35]
TABLE 1
FOOD EATEN EACH MONTH BY GRAY SQUIRRELS
IN EASTERN TEXAS
Month
Number
Stomachs
Analyzed
January
7
February
7
March
7
April
7
May
9
June
8
July
8
August
7
September
11
October
40
November
7
December
7
TOTAL
Name
Mast of pecan, oak, yaupon, blackgum, hickory, hawthorn, blackhaw ; elm buds; moth or
butterfly larvae.
Oak mast and flowers; hawthorn buds; mast of
pecan, hickory, yaupon, hornbeam buds; mushroom ; elm seed and buds ; moth or butterfly
larvae; nematodes; fungi.
Oak mast and flowers; wood fragments; moth
or butterfly larvae; acorn weevil; grass seed;
elm and hornbeam seed ; maple buds and fruit.
Oak, pecan, maple, and hickory mast; ants;
sedge seeds and roots; beech buds.
Mast of oak, hickory, blackberry, may haw,
mulberry; fungi; wood fragments; 3 species
of ants; moth or butterfly larvae and pupa; 2
species beetles; mushrooms, sedge and salvia
seed.
Mast of oak, mulberry, hop-hornbeam, ash,
blackberry; fungi; wood fragments; moth or
butterfly pupa and larvae; wasp larvae; beetle;
flesh fly.
Mast of wild plum, oak, pecan, grape; leaf
fragments;wood fragments; moth or butterfly
larvae; flies; 3 species ants.
Mast of oak, pecan, dogwood, grape; ants;
frog; unidentified weed seeds; moth or butterfly.
Mast of grape, blackhaw, pecan, oak, magnolia, elm; plantain seed; oak buds; elm buds;
moth or butterfly eggs ; miscellaneous insect
larvae.
Mast of oak, pecan, yaupon, grape, pine,
beech, walnut, palmetto, sweetgum, fungi,
buds of elm and willow; turkeyberry fruit;
buttercup ; grass; plantain; moth or butterfly
larvae; woods grass seed; beetle larvae ; oak
buds.
Mast of oak, pecan, sweetgum, palmetto, hackberry, grape; greenbrier seeds; termites; insect
larvae; mushrooms.
Mast of oak, pecan, hackberry, palmetto;
fungi ; mushroom ; moth or butterfly pupa,
miscellaneous insect larvae; unidentified roots
and tubers.
125
[36]
TABLE 2
EXPECTED YIELD OF FRESH ACORNS IN POUNDS
BY 2-INCH-DIAMETER CLASSES PER TREE
Diameter
Inches
4
6
8
10
12
14
16
18
20
22
24
26
Postoak White Oak BlackjackSandjack So. Red Oak Water Oak
Pounds
.18
.97
1.75
2.54
3.33
4.11
4.90
5.68
6.44
7.21
Pounds
.36
2.44
4.51
6.59
8.66
10.78
12.86
14.98
17.05
18.99
Pounds
.56
2.32
4.10
5.90
7.68
9.48
10.81
13.08
14.80
Pounds
1.65
2.49
3.92
5.33
Pounds
.46
.99
1.98
3.57
6.15
10.06
15.55
22.96
30.24
Pounds
.66
3.14
5.70
8.19
10.83
13.31
15.95
18.58
21.22
The pose of this squirrel eating his favorite food, a pecan, is a common
sight in the woods when that type food is most abundant.
Pecan
This fruit is one of the “ice cream” items in the squirrel’s diet. It is exceptionally high in fat content. Squirrels fortunate enough to have plenty of
pecans on their fall menu become sleek and fat for the winter to come.
Bitterpecan
This pecan is one of the natives found in East Texas closely related to the
larger domesticated pecan shown above. With regard to the health of a
squirrel, this fruit also ranks high on the preference list.
[38]
Willow Oak Acorns
As the oaks provide the mainstay food item of the squirrel, this fruit is also
an important food item on the menu. Not only are these acorns more numer.
ous than pecans of various species, they are also nutritious
Water Oak Acorns
The commercial minimum a c o r n - b earing age for the trees bearing this
fruit is 25 years and maximum is 175 years. A pound of these acorns will
average 400 in number. Trees attain a height of 80 feet. Three hybrids of
this oak occur in Texas.
[39]
Blackgum
Fruit bitter. Name derived from dark color of bark. Foliage browsed by
plyblack bear and white-tailed deer. Wood used in production of veneer,
wood, boxes, pulp, crossties. Grows to 100-foot height.
Sweetgum
Twenty-five species of birds are known to feed on this fruit. Tree produces
good seed crop every 3 years, light years between. An important timber
tree and the source of styrax, a medicinal balsamic resin, Witchhazel
Family. Used in Mexico and Europe for treating diarrhea and dysentery.
[40]
Typical Mast Producing Trees
These oak trees provide the mainstay food item for the squirrels. The oaks
rank among the world’s most noble and valuable trees. More than 300
species have been described in the literature. The mainstay food item of
the squirrels is produced by this family of trees.
Artificial Den Box
This den box was made from an ammunition case. Where ammunition boxes
of this type can be obtained in great numbers, gratifying results can be
obtained by the proper placement in woods where den trees are scarce.
This box was poorly placed in the tree, the entrance being difficult to
approach by the sauirrel.
[41]
SCIENTIFIC NAMES OF PLANTS AND ANIMALS
USED IN THIS BOOKLET
Plants :
Pecan (Carya texana)
Oak (Quercus spp.)
Yaupon (Ilex vomitoria)
Blackgum (Nyssa sylvatica)
Hickory (Carya spp.)
Hawthorn (Crataegus spp.)
Blackhaw (Viburnum rufidulum)
Elm (Ulmus spp.)
Hornbeam (Carpinus caroliniana)
Fungi (Myxomycetes)
Mushroom (Eubasidiomycetes)
Grass (Gramineae)
Maple (Acer spp.)
Sedge (Cyperus spp.)
Beech (Fagus grandifolia)
Blackberry (Rubus spp.)
May haw (Crataegus opaca)
Mulberry (Morus rubra)
Salvia (Salvia sp.)
Hop-hornbeam (Ostrya virginiana)
Ash (Fraxinus spp.)
Wild Plum (Prunus umbellata)
Grape (Vitis spp.)
Dogwood (Cornus florida)
Pine (Pinus spp.)
Walnut (Juglans nigra)
Palmetto (Sabal spp.)
Sweetgum (Liquidambar styraciflua)
Willow (Salix spp.)
Turkeyberry (Mitchella repens)
Buttercup (Ranunculus sp.)
Plaintain (Plantago sp.)
Woods grass (Uniola spp.)
Magnolia (Magnolia grandiflora)
Hackberry (Celtis spp.)
Greenbrier (Smilax spp.)
Holly (Ilex opaca)
Rattan (Berchemia scandens)
Muscadine (Vitis rotundifoliu)
Postoak (Quercus stellata)
Cypress (Taxodium distichum)
Huckleberry (Vaccinium virgutum)
Willow oak (Quercus phellos)
Overcup oak (Quercus lyrata)
Bitterpecan (Caryu texana)
Water oak (Quercus nigra)
White oak (Quercus alba)
Cow oak (Quercas prinus)
[42]
Tupelo gum (Nyssa aquatica)
Shagbark hickory (Carya ovata)
(Q uercus falcata var. pagodaefolia (Ell.) Ashe)
Moths and
(Order, Lepidoptera)
Nematode (Nematoda)
Weevil (Order, Coleoptera)
Ants (Family, Formicidae
Beetles (Order, Coleoptera)
Wasp (Family, Vespidae)
Botfly (Family, Sarcophagidae)
Frog (Amphibia)
Fox squirrel (Sciurus niger ludovicianus)
Eastern gray squirrel (Sciurus carolinensis)
Red squirrel (Sciurus hudsonicus)
Gray fox (Urocyon cinereoargenteus)
Bobcat (Lynx rufus texensis)
Mink (Mustela vison mink)
Raccoon (Procyon lotor lotor)
Red-shouldered hawk (Buteo lineatus)
Cooper’s hawk (Accipiter cooperii)
Great-horned owl (Bubo virginianus)
Barred owl (Strix varia)
Canebrake rattlesnake (Crotalus
horridus atricaudatus)
Chicken snake (Elaphe obsoleta)
Woodpeckers (Picidae)
Flicker (Colaptes auratus)
Wood duck (Aix sponsa)
Flying squirrel (Glaucomys
volans)
White-tailed deer (Odocoileus virginianus)
Wild turkey (Meleagris gallopavo)
Crow (Corvus brachyrhynchos)
Blue jay (Cyanocitta cristata)
Bobwhite quail (Colinus virginianus)
O’possum (Didelphis marsupialis)
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