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UNIVERSITY OF KANSAS PUBLICATIONS
MUSEUM OF NATURAL HISTORY

Vol. 10, No. 7, pp. 553-572, 4 pls., 3 figs.
May 4, 1959




Home Range and Movements
of the Eastern Cottontail in Kansas

By

DONALD W. JANES

UNIVERSITY OF KANSAS
Lawrence
1959



UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

Editors: E. Raymond Hall, Chairman, Henry S. Fitch,
Robert W. Wilson

Volume 10, No. 7, pp. 553-572, 4 pls., 3 figs.
Published May 4, 1959

UNIVERSITY OF KANSAS
Lawrence, Kansas

PRINTED IN
THE STATE PRINTING PLANT
TOPEKA, KANSAS
1959




Home Range and Movements
of the Eastern Cottontail in Kansas

By

DONALD W. JANES


INTRODUCTION

A knowledge of the home range and movements of the cottontail
(_Sylvilagus floridanus_) is one of the most important prerequisites
for estimating effectively its numbers and managing its populations. By
comparing results obtained from different methods, previously used, for
determining the size of the home range I have attempted to develop a
more valid procedure.

The study here reported upon was made on the University of Kansas
Natural History Reservation (Sec. 4, T. 12S, R. 20E), the
northeasternmost section of Douglas County, Kansas, approximately 6-1/2
miles north-northeast of the University campus at Lawrence. The
590-acre reservation, situated in the ecotone between the eastern
deciduous forests and the prairie of the Great Plains near the north
edge of the Kansas River Valley, has been protected as a "natural area"
since 1948 (Fitch, 1952). It consists of tree-covered slopes, and flat
grass-covered hilltops and valleys. Two limestone outcrops follow the
contours about five and 20 feet below the tops of the hills.

The 90-acre study area consists of a valley bordered on the north by a
wooded slope and on the southeast by another wooded slope adjacent to a
narrow hilltop, east of which is another wooded slope. The area is thus
an alternating series of three wooded slopes and two grass-covered,
relatively level areas.

The wooded slopes rise from the valley for about 125 feet at a grade of
approximately 16 per cent. There is a sharp increase in grade to 36 per
cent 100 feet below the top of the hills. A natural terrace 50 feet to
100 feet wide parallels the hilltop at the base of the 36 per cent
incline.

The vegetation of the northwest-facing wooded slopes has been described
by Packard (1956). It consists of American elm (_Ulmus americana_),
shagbark hickory (_Carya ovata_), chestnut oak (_Quercus
muehlenbergii_), black oak (_Quercus velutina_), and black walnut
(_Juglans nigra_), in that order of dominance. Honey locust (_Gleditsia
triacanthos_) and hackberry (_Celtis occidentalis_) are also present.
Shrubs and herbs of the lower story include greenbriar (_Smilax
hispida_), wild grape (_Vitis vulpina_), Virginia creeper
(_Parthenocissus quinquefolia_), coralberry (_Symphoricarpos
orbiculatus_), gooseberry (_Ribes missouriense_), bluegrass (_Poa
pratensis_), sedges (_Carex_ sp.), poison ivy (_Rhus radicans_), and
white snakeroot (_Eupatorium rugosum_).

The flat hilltops are covered by a mixture of grasses and forbs but are
dominated by awnless brome (_Bromus inermis_). Foxtail (_Setaria
glauca_), false redtop (_Triodia flava_), and panic grass (_Panicum
clandestinum_) also occur commonly. Awnless brome is dominant in the
valley (Pl. 46, fig. 1; Pl 47, fig. 2) except in the eastern end where
bluegrass is dominant (Pl. 45).

Near the tops and bottoms of the slopes barbed wire fences separate the
woodlands from the grasslands, which were grazed until 1948. The
borderline between woods and grasslands is well defined but woody
plants are rapidly encroaching into the grasslands. Young Osage orange
(_Maclura pomifera_), American elm, and hackberry are common trees
encroaching on the grasslands. The edge vegetation between woods and
fields (Pls. 45 and 47) includes smooth sumac (_Rhus glabra_),
coralberry and wild plum (_Prunus americana_). The lowland edges are
characterized by blackberry (_Rubus argutus_), greenbriar and
elderberry (_Sambucus canadensis_). Plates 45, 46 and 47 all show local
habitat in situations where traps were actually operated. Fitch
(1952:8-22), Leonard and Goble (1952:1015-1026) and Martin
(1956:366-372) have described parts of the Reservation that include the
study area.

I am grateful to Professor Henry S. Fitch for guiding my work, to
Professor Rollin H. Baker for suggestions and encouragement in the
early part of the study, to Mr. Robert L. Packard for certain trapping
records that supplemented my own, and to Professor E. Raymond Hall for
valuable suggestions. Norma L. Janes, my wife, typed the manuscript.
Photographs were taken by me. The State Biological Survey of Kansas
provided funds, equipment, and transportation.


METHODS AND TECHNIQUES

Schwartz (1941), Dalke and Sime (1938), Dalke (1937 and 1942),
Hendrickson (1936), and Allen (1939) estimated the home range of the
cottontail by drawing, on a map, straight lines that connected all
marginal points of capture in live-traps. The resulting home ranges
were polygonal figures. Haugen (1942) altered this method by drawing
lines that connected points midway between the actual points of capture
and the next outermost traps in the grid. Fitch (1947) used a method
for enclosing all points of capture in a circle or ellipse that
represented the home range boundaries and expressed home range as the
diameter of these figures. Another method, which has been used to
determine the home range of birds, is to map the movements of an
individual as it is observed. Stebler (1939) suggested the use of
tracking records to determine home range. Connell (1954) expressed home
range of cottontails as the average distance traveled from a computed
center of activity. The method was originally proposed by Hayne (1949).

The methods used by other investigators to calculate the home range of
the cottontail have yielded estimates varying from 0.1 acre to 100
acres. Such wide variations in the estimated size of home range may
result from the use of different methods and from insufficient data.
The data obtained from live-trapping are not fully adequate because
traps cannot sample, in time and space, the entire home range of an
individual. Also, "trap habit" or "trap shyness" may distort the
apparent shape of the home range. In order to compare these methods I
have calculated home range from my data by each of five different
methods. The results are shown in Table 1.

No two methods yielded exactly the same results. To utilize all
available data for each individual, I recorded on a map the locations
of capture in live-traps, nests and forms, locations where the animal
was observed in the field and the routes that it took between them. At
the end of the study a line was drawn on the map to enclose the areas
where the cottontail was known to have been.

Live-traps were operated intermittently at 130 stations between
December 8, 1954, and February 10, 1956. Sixteen cottontails were
marked in the same area by Robert L. Packard in 1954. Data from 7850
trap nights were used in this study. The traps were set at fifty-foot
intervals and the pattern approximated that of a grid in habitat
favorable for cottontails such as at edges of woodland. In wooded areas
traps were placed at fifty-foot intervals parallel to the edges. Traps
were not set on areas of poor habitat where neither cottontails nor
their sign were observed.

The traps were operated eight to twelve days and closed for two to five
days intermittently throughout the trapping period except in the months
of April to August, 1955, when trapping was unsuccessful because the
cottontails then were not attracted by bait.

Two kinds of traps were used in my study: those made by the National
Live Trap Company and those described by Fitch (1950). Both types
performed well and were serviceable under ordinary field conditions.
Experiments were made periodically throughout the trapping period to
determine which bait was most attractive to cottontails and least
attractive to birds, rodents, skunks, raccoons, and opossums. All of
these animals hindered operations by stealing bait and springing traps.
Corn, scratch-feed, carrots, parsnips, tomatoes, lettuce, apple,
cabbage, raisins, sorghum, sugar candy, and onions were used as bait.
Corn and scratch-feed attracted cottontails best in all seasons. Corn
was superior to scratch-feed, which was quickly stolen by small birds
and rodents. Eighty-nine cottontails (40 females, 49 males) were
captured in the course of the study.

Cottontails were marked individually at the time of first capture. When
necessary, the markings were renewed at later captures; in all such
instances the same color codes and numbers were retained for each.
Markings were of four types: numbered ear tags, colored ear ribbons,
colored tail fur, and colored feet. It was intended to make each
individual cottontail recognizable in a trap or in the field.
Occasionally when a predator had killed and eaten a cottontail the tail
and feet remained and, when dyed, they provided important clues to the
identity of the individual. However, the color of the feet is not
ordinarily discernible in the field while the rabbit is alive.

Monel metal ear tags (size No. 4, National Band and Tag Co.) were
punched through the lateral or posterior fold of the ear close to its
base (Pl. 48), one in each ear as insurance against possible losses.
However, only three tags were pulled out of the ears and lost in the
course of this study. In no instance was identity of an individual
cottontail lost. The tags caused no damage to the ears over a period of
21 months.

Trailing in snow is an effective method of studying the daily
activities. The record preserved by the tracks becomes somewhat
confused after the snow has lain on the ground for more than one night,
and after the third night it is impossible to read the surface of the
snow. The first day of thaw usually ends tracking because the
investigator loses the trail when it crosses a patch of bare ground.
The use of a dye on the feet of the individual to be trailed eliminates
much of the difficulty of determining which tracks are to be followed.
One or more feet can be dyed when the investigator handles the animal
in releasing it from the trap. The trail of dyed footprints is
distinguishable from all other rabbit tracks in the area. Even when
only patches of snow remain, the animal can be followed by checking the
edges of the snow for the emerging footprints of the marked rabbit. The
same dye is used to color the tails. The color persists in the
footprints for about three hours, over a distance of 600 to 800 yards.
The animal leaves only a small spot in each footprint, but when it
pauses, the mark is large. Red dye makes the most conspicuous mark in
the snow.

Thirty-one rabbits were trailed 68 times with one to six records for
different individuals. Almost two-thirds of the trailing records
pertain to males, which were caught more easily than females while snow
was on the ground.

The trail, for both sexes, in those individuals released and followed
immediately was longer than in individuals released and allowed to move
away before they were followed. The area ranged over by a trailed
individual was not significantly greater in either case. The area
ranged over was greater by day than by night. Individuals continued to
move while being followed in the day, but stopped to forage and look
about at night.

Records were obtained by identifying cottontails that I flushed from
forms as I walked through the study area, sometimes using a
noise-making device or dragging a rope. Regular search was made along
the hilltop rock outcrops, under which hiding cottontails could be
identified with the aid of a flashlight. Forms in brush piles, and
thickets were visited and the inhabitants identified. Other persons,
working on the study area, supplied some of the records of cottontails
that were seen alive or found dead. Also through binoculars or a
telescope I watched movements of undisturbed individuals. Twenty-three
individuals were identified 59 times. Nine females were seen 28 times
and 14 males were seen 31 times. Sixty-five other individuals were
seen, but could not be identified in the field.


MOTIVATION AND EXTENT OF MOVEMENTS

The home range is an area in which an animal carries on its normal
activities of eating, resting, mating, caring for young, and escaping
from predators. The cottontail establishes a definite home range and
may live its entire life within this area, which permits familiarity
with food sources, hiding places, and escape routes.

The cottontail usually establishes its home range in the area where it
was born, being semi-gregarious and tolerant of crowding. Eight
cottontails that were captured and marked as young remained in the area
of original capture after becoming adults. Two of them lived 17 months
in the same area, two lived 14 months, two lived 13 months, one lived
12 months and one lived eight months. No young were observed to have
moved to another home range after they matured, although some may have
moved off the study area and thereby escaped observation.

Young become independent and are seen foraging and moving about by the
time they weigh 200 to 300 grams, at an age of four to six weeks. They
associate with other young of the same litter and neighboring litters,
and frequently frolic together. When two to three months old and
weighing 400 to 700 grams they begin to live a more solitary life and
usually rest alone in forms. Fourteen young between one and six weeks
of age never were recorded to have moved more than 150 feet.

The population reaches its peak in August or September; home ranges
varying in size from one-half acre (in young ranging in size from 150
grams to 800 grams) to 12 acres, in adults, are superimposed upon each
other. In a woodland area of approximately 21 acres 33 cottontails were
living together in September, 1955.

As the growing season ends and winter approaches, the amount of food
available to the cottontail decreases and the cover becomes sparser
(Pls. 45 and 46); predators, disease, and weather take their toll of
the young. The survivors must move farther to find adequate food and
cover. The home range of the cottontail in the first winter is
overlapped by the home ranges of the other members of the same litter,
and members of other litters, as the home range is enlarged to
approximately its full size. By April the population reached its annual
low point; nine of the original 33 cottontails were known to have
survived on the 21-acre area of northwest-facing wooded slope south of
the pond.

Foremost among the needs of the cottontail are food and cover. Daily
movements motivated by these needs are the most frequent and most
extensive that it makes. Movements such as are associated with courting
and mating, escaping severe weather, escaping from predators, and
caring for young are seasonal or irregular in occurrence.

Because the abundant vegetation of summer provides adequate food and
cover, movements made while foraging and seeking concealment are less
extensive than those made in winter when leafy vegetation is absent and
food is scarce. The average length of trails of foraging cottontails
was 175 feet per day in summer (11 individuals observed without
disturbance) and 325 feet per day in winter (22 individuals trailed or
observed without disturbance).

In the spring and summer cottontails forage mostly near woodland edges
for grass and herbs, and usually wander no more than 40 feet into the
grasslands from the protection of woodland edges and thickets. In
autumn and winter cottontails forage in woods and along woodland edges
for bark of trees and shrubs and for fallen fruits of trees. Ninety-two
per cent of all fecal pellets found in grassland were within 40 feet of
cover suitable for cottontails.

Movements made by the cottontail while foraging appear aimless; typical
behavior consists of progression with a hesitant gait of two or three
hops, a stop to eat, another series of hops and another stop.
Footprints made by this movement are about 12 inches apart. With
occasional spurts of hopping the individual moves perhaps ten to twelve
feet where it stops and begins to eat again. The area in which the
individual forages is usually elongated with its long axis parallel to
the edge except in areas of uniform habitat (such as large patches of
coralberry) where the area covered tends to be more nearly circular.
Cottontails observed foraging were estimated to utilize 10 to 20 per
cent of the home range area in one evening. Paths or runways are not
ordinarily utilized by foraging cottontails.

In seeking protection from predators or from the weather, cottontails
move farther in winter than in summer. The average length of trails of
cottontails flushed by me in the study area was 80 feet in summer and
210 feet in winter.

When cottontails were released from live-traps they ran an average of
30 feet before stopping to look about. Cottontails always ran toward
the densest cover within 50 feet of the point of release. Ten per cent
of the cottontails released from live-traps did not stop running until
out of sight (always more than 30 feet).

Movements made by cottontails escaping from predators differ from
movements made while foraging. The gait is a full run, often eight to
ten feet between footprints in snow; the trail is either straight or
slightly zig-zag. If possible, the individual will take refuge in a
hiding place such as a rock outcrop, brush pile, or thicket. Eight
cottontails emerged from such hiding places an average of 22 minutes
after the disturbance ceased.

If unable to find a hiding place a pursued cottontail will run 600 to
1200 feet while circling and returning to the area from which it ran.
If not closely pursued, it will usually (in 68 per cent of the
instances) not enter hiding places, but continue to run ahead of the
pursuer. Of 70 released from live-traps and followed, 23 sought refuge
in hiding places. The others ran slowly (4 to 7 feet between footprints
in the snow) with frequent pauses to look and listen; they usually
succeeded in keeping out of my sight. Twelve times the trails of
cottontails followed in this manner passed near a form, or other
resting place; always the cottontails had paused at the resting place,
and twice the individual went into the resting place and ran out again
when I approached. Resulting trails were almost circular, covering most
(70-90 per cent) of the home range; sometimes three or four complete
circuits were made. The trails made when I pursued cottontails ranged
in length from 800 to 3,000 feet. A trail recorded for an individual on
one night was almost identical with another trail for the same
individual recorded another night. The cottontail is not easily driven
out of its home range. Paths or runways are used by cottontails
escaping from predators in dense vegetation along fence lines, in
thickets, or brush piles, or in snow that is eight or more inches deep.

Most of the year cottontails rest in forms of grass or brush near
woodland edges but in extremely cold or hot weather they seek the
greater protection of the woods. Movements are limited to the woodlands
in severe weather, especially when deep snow makes travel difficult.

Hilltop rock outcrops on the area provide excellent protection for the
cottontail especially from low temperatures and freezing rain or
blowing snow. Eighty per cent of the cottontails resting under the rock
outcrops were found in severe winter weather. Fifteen per cent were
found in severe summer weather, and five per cent were found at times
when the weather was not severe. Undercut creek banks and exposed tree
root-systems in eroded gullies were favorite hiding places. Brush that
had accumulated in the ravines and stream beds also was used for cover
by the cottontail.

In heavy rain a cottontail may move along, neither hopping nor running,
with its body close to the ground, head low, ears laid back. Losing its
customary alertness it may pass a person without seeing him. At times,
I have been able to approach almost close enough to seize one of the
miserable creatures. In deep snow cottontails may progress with long
bounds carrying them high enough vertically, to clear the surrounding
snow.

Courting activities were seen only in evening. Four male cottontails
and three females were observed to move an estimated 1200 feet in an
evening (1-1/4 hours) while chasing each other around in an area of
less than an acre. It is presumed that this activity was in addition to
normal movements made while foraging.

Seven females known to be pregnant or lactating were not observed to
move more than 100 feet away from their centers of activity. Their
nests were never found. At the same time the males were moving over
much larger areas.

The cottontail is most active in the evening or early morning. Of those
for which time of capture in live-traps was known 70 per cent were
captured in the evening between dusk and 11:00 P.M., 10 per cent were
captured between 11:00 P.M. and dawn, and 20 per cent were captured
after dawn. Nocturnal rodents and carnivores often stole bait in the
night; the percentage of capture of cottontails after dawn might have
been larger had bait remained in all the traps.

Except for those flushed, cottontails were seldom seen by day. In walks
through the study area approximately three times as many cottontails
were flushed at night as in the daytime. On cloudy days cottontails
were active longer than on bright days. On dark nights more cottontails
were captured in live-traps between 11:00 P.M. and dawn than on bright
moonlight nights.

Cottontails were more active (as determined by trap success and
frequency of observation) at temperatures between 0° F. and 33° F. than
at temperatures between 33° F. and 55° F. Activity of the cottontail
increased as the temperature of the air decreased. Activity increased
in proportion to the percentage of ground covered by snow. Activity of
the cottontail decreased as precipitation increased; there was less
activity in rain than in snow and less activity in wet snow than in dry
snow. Activity did not vary significantly with depth of snow until snow
was more than 8 inches deep, when activity decreased abruptly.

The average of the longest distance traveled between captures for
cottontails whose entire home ranges were thought to have been sampled
was 900 feet for males and 684 feet for females. The average of the
maximum distance across the home range for cottontails whose home range
had been thoroughly sampled was 1019 feet for males, and 936 feet for
females.

The home range is used by the cottontail in different ways, depending
on the needs of the individual and the condition of the habitat. In
uniform habitat the home range is roughly circular and is used most
near its center and least toward its periphery. The entire home range
is traversed every four or five days. The center of the home range has
been called the "center of activity" (Connell, 1954).

In habitat of alternating woodland and grassland, such as that on the
University of Kansas Natural History Reservation, two centers of
activity often developed in the home range of a cottontail, at opposite
edges of a tract of woodland. The individual concentrated its movements
near one center for three to five days then moved to the other center.
Pursuit by a predator, random movement, or other cause may be
responsible for shift from one edge to another.

PLATE 45

[Illustration: FIG. 1. "House Field" viewed from the northeast corner,
looking southwest, March 3, 1956, showing the condition of vegetation
in winter. Traps were operated on a 50-foot grid throughout this area.]

[Illustration: FIG. 2. Same area as above, on July 10, 1956, showing
the condition of vegetation in summer.]

PLATE 46

[Illustration: FIG. 1. View southeast from the north edge of "Picnic
Field" showing condition of the vegetation on December 3, 1954. Trap
lines were placed along woodland edge from which this picture was
taken, along road where vehicle is parked, along creek beyond road,
along edge of field beyond creek, and along edge of woods in
background.]

[Illustration: FIG. 2. Summer aspect of the vegetation, on July 14,
1955; same view as shown in Fig. 1.]

PLATE 47

[Illustration: FIG. 1. Condition of vegetation along woodland border
northeast of Reservation headquarters on December 3, 1954. Camera was
facing southwest. Traps were operated along this edge and in woods to
right and in background.]

[Illustration: FIG. 2. Condition of vegetation at edge of "House Field"
on July 14, 1955. Scale is shown by 4-1/2 foot tripod. Brome grass was
approximately two feet high. Traps were operated in a grid in this
area.]

PLATE 48

[Illustration: FIG. 1. Cottontail in bag with ear protruding, ready for
marking with nylon ribbon and metal ear-tag shown in upper right hand
corner. × 1/4.]

[Illustration: FIG. 2. Cottontail bearing ear-tags and ribbon. × 1/4.]

When moving undisturbed through the woods cottontails usually do not
pause to forage or associate with other cottontails, but keep to a
straight route except in severe weather, when, as noted above, they
find resting places in the woods. Ninety-two per cent of the
cottontails captured in live-traps were captured within 100 feet of a
woodland edge; six per cent were captured in the woods, more than 100
feet from an edge, and two per cent were captured in grassland more
than 100 feet from the edge. In winter, when the air temperature was
less than 20° F., 22 per cent of the cottontails were captured
in the woods more than 100 feet from the edge.

The maximum distance between two centers of activity of an individual
was 700 feet, average 550 feet. If two centers of activity were
maintained, the cottontail usually traversed the entire home range
every seven to 11 days.

In no case was a cottontail known to have lived in two woodland edges
which were separated by open grassland. Cottontails usually did not
move more than 75 feet from suitable cover. In winter when herbaceous
vegetation was dormant cottontails did not cross open fields.

Forms in grass clumps were the usual resting place for cottontails, but
others in brush piles, rock outcrops, and tree stumps were also used.
On the average a cottontail maintained 3.5 forms. If disturbed
repeatedly at a form, a cottontail would permanently desert it. On
seven occasions a cottontail used a form that had been used by another
within 24 hours. Three cottontails used the same shelter under a rock
ledge in five days; one was under the ledge on December 17, 1955, and
another was there on December 18. The first was there again on December
20 and a third was there on December 21. The original cottontail had
returned by January 2, 1956. There may be 20 to 30 resting places used
by cottontails within a single home range area since five to seven
cottontails may live there as co-occupants at one time. Two
cottontails, both males, lived together in a _Smilax_ thicket for three
weeks, resting within 15 inches of each other. Occasionally a female
was present in the same thicket, and rested about three feet from the
males.

A male trapped on land adjoining the Reservation and confined overnight
at the Reservation headquarters escaped the next day and was seen 32
days later, 1800 feet from the point of escape, back in the area where
it was originally captured.

A female confined for observation, escaped and ran in the direction
opposite from her home. Subsequently she was seen on four different
occasions, over a period of one month, in her original home range,
1,100 feet from the point where she escaped. Both these animals which
made homing movements had been removed in cloth bags from their homes.

Another cottontail removed from its home range and taken to the
laboratory building to be marked, escaped and ran to a nearby wooded
hillside without pursuit where it could be observed because of snow on
the ground and lack of leaves on the trees. The animal ran and hopped
about over a one-half acre area. Its movements seemed to be unoriented
and it frequently stopped and stood on its hind legs in order to look
about. After 10 minutes of this behavior, a red-tailed hawk (_Buteo
jamaicensis_) screamed as it flew overhead. The cottontail, stimulated
by seeing and/or hearing the hawk, ran faster, moving in circles until
it disappeared from view five minutes later. When last observed the
cottontail was 1,700 feet from its home range and was headed in the
opposite direction. It had passed several potential shelters but had
not attempted to use them, presumably because it was not familiar with
the area. Although for several months afterward traps were operated in
the cottontail's home range area and in the area where it escaped, the
animal was never recaptured.


SIZE AND SHAPE OF HOME RANGE

Of the 89 cottontails observed in the study, 35 were captured in
live-traps only once and were never seen in the field or trailed. The
remaining 54 served for calculation of home range by one or more
methods. The minimum, maximum and average home ranges for these 54
individuals were calculated by each of five methods. All individuals
for which any area was recorded were included in the average.
Incomplete home ranges lower the averages. According to the most
reliable method (Composite Method) 30 male cottontails had home ranges
of between 0.46 acre and 12.19 acres and 24 female cottontails had home
ranges of between 0.46 acre and 12.62 acres. The average for males was
5.05 acres and the average for females was 4.81 acres. The average for
all 54 cottontails was 4.86 acres.

Because of irregularities in live-trapping and field observation some
cottontails were more intensively studied than were others; one
cottontail was followed one time only, while another was trapped 26
times, followed three times, and seen in the field six times. It was
necessary to determine which cottontails had been studied sufficiently
to determine the approximate extent of their home ranges.

[Illustration: FIG. 1. Correlation between average size of home range
and number of "peripheral points" (marginal records, which form angles
when the range is outlined). On the average, a sufficient number of
records to yield approximately nine peripheral points must be obtained
before the full extent of the home range is revealed.]

The average area, in acres, of home range was plotted, on a graph,
against the number of peripheral points (Figure 1). When a home range
had nine or more peripheral points, on an average, the size of home
range did not increase significantly with additional captures,
observations in the field, or records of trails. Home ranges with less
than nine peripheral points were likely to be increased in size with
each new observation. A similar situation has been shown by previous
authors who have plotted the size of home range against number of
captures in live-traps, where only live-trapping was used to gather
data. Therefore, in my study, home ranges with nine or more peripheral
points were considered to be adequately studied.

Data for eighteen cottontails that had been studied sufficiently to
determine the full extent of their home ranges were used to calculate
minimum, maximum, and average home range by each of five methods (Table
1). The methods used by Schwartz (1941), Dalke and Sime (1938) and
Allen (1939) yielded results which were lower than any others,
presumably because only live-trap data were used and because straight
lines were used to connect traps in which cottontails were captured.
The "composite method" was considered the most reliable because it
utilized all data gathered for each individual and because with this
method the home range boundaries were drawn to enclose all areas in
which the cottontail lived and excluded all areas in which the
cottontail was not known to have been. The method used by Fitch (1949)
agreed most closely with the "composite method" and suggests to me that
the home range of animals can be estimated with reasonable accuracy by
this method when field observation or trailing are not feasible. The
composite method is superior to others for studying the home range and
movements of cottontails.

Of the individuals whose entire home ranges had been thoroughly
studied, nine males had home ranges of between 4.72 acres and 12.19
acres with an average of 8.92 acres; nine females had home ranges of
between 2.42 acres and 12.62 acres with an average of 7.76 acres. The
average size of home range for both sexes was 8.34 acres (Table 1).

TABLE 1.--HOME RANGES, IN ACRES, OF 18 COTTONTAILS ON THE
RESERVATION IN 1956, COMPUTED BY FIVE DIFFERENT METHODS.

=======================================================================
                      |     | Number of  | Average | Maximum | Minimum
        Method        | Sex | individuals|  area   |  area   |  area
----------------------+-----+------------+---------+---------+---------
Allen (1939),         | (M) |      9     |   2.00  |   6.78  |   .30
Dalke and Sime (1938) | (F) |      9     |   2.54  |   7.20  |   .35
and Schwartz (1941)   | all |     18     |   2.27  |   7.20  |   .30
                      +-----+------------+---------+---------+---------
                      | (M) |      9     |   4.01  |  12.89  |  1.05
Fitch (1947)          | (F) |      9     |   5.68  |  11.50  |  1.84
                      | all |     18     |   4.85  |  12.89  |  1.05
                      +-----+------------+---------+---------+---------
                      | (M) |      9     |   7.20  |   --    |   --
Fitch (1949)          | (F) |      9     |   9.00  |   --    |   --
                      | all |     18     |   8.40  |   --    |   --
                      +-----+------------+---------+---------+---------
Tracking and          | (M) |      9     |   8.74  |  11.15  |  3.54
field observations    | (F) |      9     |   8.62  |  12.18  |  5.51
                      | all |     18     |   8.69  |  12.18  |  3.54
                      +-----+------------+---------+---------+---------
Tracking and field    | (M) |      9     |   8.92  |  12.19  |  4.72
observations plus     | (F) |      9     |   7.76  |  12.62  |  2.42
live-trapping         | all |     18     |   8.34  |  12.62  |  2.42
----------------------+-----+------------+---------+---------+---------

[Illustration: FIG. 2. Maps showing home ranges of cottontails in
relation to woodland and open fields on the study area. One inch equals
approximately 470 feet. Each home range is shown slightly rounded from
the polygonal figures obtained by connecting actual points where the
animal was recorded. _Upper Left._ An area of 4.6 acres occupied by a
cottontail in winter, increased to 6.5 acres in summer by the animal
crossing a narrow grassland strip to another woodland edge. _Lower
Left._ Showing increasing size of home range of a female cottontail; in
July, 1954 (at age of three weeks), she had a range of .25 acre;
September, 1954, 1.5 acres; December, 1954, 8 acres; and December,
1955, 11 acres. _Right Half._ Two home ranges of a cottontail which
moved from its original area to occupy a new one 410 feet farther north
across a field in September and October, 1955.]

Cottontails range over a larger area in summer than they do in winter
because suitable cover and food is more abundant in summer. One
cottontail (Figure 2, upper left) lived in a woodland home range of 4.6
acres in the winter but increased the range to 6.5 acres in summer by
crossing the narrow overgrown end of a field to another woodland area.
Another cottontail (Figure 3, top part) lived in a woodland home range
of 7.9 acres in winter but in summer increased the home range to 9.5
acres by including also a part of an adjacent field. Other cottontails
increased their home ranges in summer by five to 15 per cent.

On the average, male cottontails had a larger (by 13 per cent) home
range than females probably because of the increased activity of males
in the breeding season and the decreased activity of females when
pregnant and caring for young. Nevertheless, some of the largest home
ranges measured were those of females.

[Illustration: FIG 3. Diagrams showing home ranges of cottontails in
relation to woodland and open fields on the study area. One inch equals
approximately 545 feet. Each home range is shown slightly rounded from
the polygonal figures obtained by connecting actual points where the
animal was recorded. _Upper._ Winter range of 7.9 acres (solid line)
increased to 9.5 acres in summer by area in dashed line. _Lower._
Overlapping home ranges of four of the many cottontails living on the
study area. Each of the four cottontails occupied approximately the
same home range throughout the year.]

The size of the home range in immature cottontails varies between 0.1
acre and 4.0 acres, depending on the age and size of the individual.
Fourteen young cottontails between three and six weeks of age did not
leave areas of approximately one acre in each instance. Nine
cottontails between six weeks and 18 weeks of age lived in areas of
about two acres. By the time cottontails are four to five months old
they inhabit a home range of four to eight acres.

One cottontail (Figure 2, lower left) born in July, 1954, was estimated
to have wandered over approximately 0.25 acre at an age of three weeks.
In September this cottontail occupied a home range of one and one-half
acres. By December it was five months old and occupied an area of about
eight acres. In the next year it enlarged its home range to 11.5 acres.

The cottontail usually settles down in one area and stays there until
it dies. Changes from one home range to another are unusual, but minor
shifts, in response to changes in vegetation and weather, are common.
In one exceptional instance (Figure 2, right) a male cottontail,
occupying a home range of 11.2 acres in a woodland, suddenly shifted to
a new area that barely overlapped its former home range at one edge.
Two months after the change was first noticed the cottontail was living
in a new home range of 6.6 acres 300 feet from its original home range.
In changing from one home range to the other the cottontail traveled
along a dry stream bed and was captured there three times.

Maps of the home ranges of four of those 18 cottontails for which
sufficient data were collected to determine the size of home range are
shown in the lower part of Figure 3.


SUMMARY AND CONCLUSIONS

The home range and movements of the cottontail were studied on a
90-acre area of the University of Kansas Natural History Reservation
from February, 1954, to March, 1956. Eighty-nine cottontails were
identified in the field 59 times, trailed 70 times and captured in
live-traps 326 times in 7,850 trap nights. Home range of the cottontail
was calculated by five methods, using the same set of data, and the
results were compared. A composite method was used, which permitted the
use of more data than any other one method.

The maintenance of a home range is of survival value to the cottontail.
Knowledge of the home range is of value to man when control or
propagation of cottontail populations is desired. Cottontails establish
a home range where they are born and enlarge it to nearly full size the
first winter. Home ranges of cottontails are overlapped by those of
others regardless of sex or age. No territory is maintained.

The cottontail makes movements to forage, to seek cover from predators
and the weather, to reproduce, build nests, care for young, keep pace
with changes in vegetation through the year, and escape unusually
severe climatic conditions. Movements may be caused by desire for
acquaintance with surroundings and other animals, escape from
undesirable surroundings or animals, or merely release of nervous
energy.

When foraging, cottontails moved 175 to 325 feet per day, mostly near
woodland edges, and used from 10 to 20 per cent of the home range. When
escaping from predators cottontails moved 30 to 1200 feet and used 5 to
70 per cent of their home ranges, depending on the type of pursuit.
Some cottontails that were followed, ran in almost circular courses for
as far as 3000 feet and covered as much as 90 per cent of their home
ranges. Paths or runways were not used except in deep snow or very
dense vegetation. Movements were limited by deep snow. When
temperatures were unfavorably high or low, cottontails sought cover
deep in the woods or under rock outcrops, and in dry stream beds. In
moderate weather resting places in grass forms, brush piles and
thickets were used.

Both males and females moved farther in the breeding season than in the
rest of the year, but females that were caring for young in summer and
late spring moved shorter distances than they did when not so engaged
in autumn and winter.

Cottontails were most active at dawn and especially, dusk, and were
more active on dark nights than on moonlight nights. Cottontails were
most active when the air temperature was between 0° F. and 33° F. and
when rain was not falling. Activity increased as the percentage of
ground covered by snow increased and as the abundance of food
decreased. Activity did not vary with physiological condition except
that as body weight decreased activity increased--probably because of
lack of food.

The home range is used most intensively near centers of activity that
are near woodland edges or in other areas of good cover. Cottontails
often ranged through the woods and along edges but did not cross open
areas more than 75 feet wide. Cottontails use their home range most
intensively in winter when they are forced to move long distances in
poor cover, searching for food. More than one cottontail may use sites
of good cover at the same time and two or three used the same resting
place at different times.

Two instances of homing were observed; cottontails moved 1,100 and
1,800 feet to return to their home ranges, but one cottontail that
escaped 1700 feet from home failed to return.

The average home range of 18 cottontails for whom adequate data were
gathered was 8.34 acres. The home ranges of males averaged 1.16 acre
larger than those of females. In summer, cottontails increased their
home ranges 5 to 15 per cent by taking advantage of cover provided by
the more abundant vegetation. Cottontails three weeks to five months of
age lived in home ranges of between 0.1 and 4.0 acres and enlarged
their home ranges almost to their ultimate full size in the first
winter.


LITERATURE CITED

ALLEN, D. L.

    1939. Michigan cottontails in winter. Jour. Wildl. Mgt.,
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CONNELL, J. H.

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DALKE, P. D.

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DALKE, P. D., and SIME, P. R.

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FITCH, H. S.

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HALL, E. R.

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HAUGEN, A. O.

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HAYNE, D. W.

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HENDRICKSON, G. O.

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JANES, D. W.

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LEONARD, A. B., and GOBLE, C. R.

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MARTIN, E. P.

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PACKARD, R. L.

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SALMAN, D. H.

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SCHWARTZ, C. W.

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STEBLER, A. M.

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