• TABLE OF CONTENTS
HIDE
 Title Page
 Half Title
 Acknowledgement
 Table of Contents
 List of Tables
 List of Figures
 Abstract
 Introduction
 Study animal
 Study area
 Methods
 Results
 Discussion
 Literature cited
 Biographical sketch
 Certification signatures






Group Title: Florida Cooperative Fish and Wildlife Research Unit Research Work Order no. 9
Title: Fox squirrel home range and mast crops in Florida
CITATION PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00073783/00001
 Material Information
Title: Fox squirrel home range and mast crops in Florida
Physical Description: ix, 68 leaves : ill. ; 28 cm.
Language: English
Creator: Kantola, Angela Torres, 1961-
Publication Date: 1986
 Subjects
Subject: Fox squirrel   ( lcsh )
Squirrels -- Habitat -- Florida   ( lcsh )
Forest Resources and Conservation thesis M.S
Dissertations, Academic -- Forest Resources and Conservation -- UF
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Thesis: Thesis (M.S.)--University of Florida, 1986.
Bibliography: Bibliography: leaves 64-67.
Statement of Responsibility: by Angela Torres Kantola.
General Note: Typescript.
General Note: Vita.
Funding: This collection includes items related to Florida’s environments, ecosystems, and species. It includes the subcollections of Florida Cooperative Fish and Wildlife Research Unit project documents, the Sea Grant technical series, the Florida Geological Survey series, the Coastal Engineering Department series, the Howard T. Odum Center for Wetland technical reports, and other entities devoted to the study and preservation of Florida's natural resources.
 Record Information
Bibliographic ID: UF00073783
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 000877462
oclc - 14944615
notis - AEH5155

Table of Contents
    Title Page
        Title page
    Half Title
        i
    Acknowledgement
        ii
        iii
    Table of Contents
        iv
    List of Tables
        v
    List of Figures
        vi
        vii
    Abstract
        viii
        ix
    Introduction
        Page 1
        Page 2
        Page 3
    Study animal
        Page 4
        Page 5
    Study area
        Page 6
        Page 7
        Page 8
    Methods
        Page 9
        Mast monitoring
            Page 9
            Page 10
            Page 11
        Nest counts
            Page 12
        Capture and handling
            Page 13
            Page 14
        Telemetry and related equipment
            Page 15
            Page 16
        Statistical methods
            Page 17
            Page 18
    Results
        Page 19
        Mast production
            Page 19
            Page 20
            Page 21
            Page 22
            Page 23
            Page 24
            Page 25
            Page 26
            Page 27
            Page 28
            Page 29
            Page 30
            Page 31
        Home range
            Page 32
            Page 33
            Page 34
            Page 35
            Page 36
            Page 37
            Page 38
            Page 39
            Page 40
            Page 41
            Page 42
            Page 43
            Page 44
            Page 45
        Nests
            Page 46
            Page 47
            Page 48
            Page 49
            Page 50
            Page 51
            Page 52
            Page 53
            Page 54
            Page 55
    Discussion
        Page 56
        Page 57
        Page 58
        Home range
            Page 59
        Nests
            Page 60
            Page 61
            Page 62
            Page 63
    Literature cited
        Page 64
        Page 65
        Page 66
        Page 67
    Biographical sketch
        Page 68
    Certification signatures
        Page 69
        Page 70
Full Text











FOX SQUIRREL HOME RANGE AND MAST CROPS IN FLORIDA


by

Angela Torres Kantola

Florida Cooperative Fish and Wildlife Research Unit
117 Newins-Ziegler Hall
University of Florida
Gainesville FL 32611






Final Report

Research Work Order No. 9

July 1, 1986



Supported by:

U.S. Fish and Wildlife Service
Washington, D.C.


through the
Florida Cooperative Fish and Wildlife Research Unit
117 Newins-Ziegler Hall
University of Florida
Gainesville FL 32611















FOX SQUIRREL HOME RANGE AND MAST CROPS IN FLORIDA


By


ANGELA TORRES KANTOLA


















A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN
PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE DEGREE OF MASTER OF SCIENCE




UNIVERSITY OF FLORIDA


1986















ACKNOWLEDGMENTS


This study was funded by the Florida State Museum and the U. S.

Fish and Wildlife Service through the Florida Cooperative Fish and

Wildlife Research Unit, University of Florida.

The advice and guidance provided throughout the study by my

committee was most helpful. Many thanks go to my committee chairman and

principal advisor, Dr. Stephen R. Humphrey, Florida State Museum, for

his valuable support and direction. Committee members Drs. John F.

Eisenberg and Melvin E. Sunquist, Florida State Museum, Dr. Michael W.

Collopy, School of Forest Resources and Conservation and unofficial

committee member Dr. George W. Tanner, School of Forest Resources and

Conservation, gave additional helpful suggestions.

The administrative support of supervisors Drs. Thomas J. O'Shea and

Galen B. Rathbun, U. S. Fish and Wildlife Service, and unofficial

committee member Dr. H. Franklin Percival, Florida Cooperative Fish and

Wildlife Research Unit, was very beneficial and most appreciated.

This project would have been impossible without the efforts of

numerous volunteers. 0. Blodgett, R. Newberry, S. Brand, J. Duffey,

R. Pedlow, A. Venables, K. Whitlock, A. Williams, and others spent many

hours in the field, assisting with squirrel trapping and mast

monitoring.










I give special thanks to my husband, Ed for his constant support and

understanding, and to my parents, Dr. and Mrs. Buenaventura Torres, for

their encouragement throughout my academic career.






















TABLE OF CONTENTS

Page

ACKNOWLEDGEMENTS..... ............................. ... .............. i

LIST OF TABLES...................................................... v

LIST OF FIGURES....................................................vi

ABSTRACT ...........................................................vii

INTRODUCTION........................................................1

STUDY ANIMAL.........................................................4

STUDY AREA... .................................................... 6

METHODS..............................................................9
Mast Monitoring................. ........................9
Nest Counts......................................................12
Capture and Handling..........................................13
Telemetry and Related Equipment................................15
Statistical Methods............................................ 17

RESULTS... .........................................................19
Mast Production........... .......................................19
Home Range.............................. ..... ................... 32
Nests........................................ ..................46

DISCUSSION..........................................................56
Food Resources.................... ............................. 56
Home Range......................................................59
Nests............................................ .............60

LITERATURE CITED..................................................64

BIOGRAPHICAL SKETCH... .............................................68





















LIST OF TABLES

Table Page

1 Summary of analysis of variance on transformed counts of
turkey oaks acorns on the Citrus Tract 20

2 Turkey oak acorn production on the Ordway Slope 21

3 Turkey oak acorn production on six areas of the Ordway
Preserve 23

4 Summary of analysis of variance on transformed counts of
turkey oak acorns on six areas of the Ordway Preserve
and on two of those areas within the Squirrel Study Area
(1983) 24

5 Longleaf pine cone production on five areas of the
Ordway Preserve 26

6 Summary of analysis of variance on transformed counts of
longleaf pine cones on five areas of the Ordway Preserve
and on two of those areas within the Squirrel Study Area
(1983 and 1984) 27

7 April temperatures 1982-1985, Gainesville 29

8 Weights and body measurements of captured fox squirrels 30

9 Dates of radiotracking sessions and number of locations/
squirrel in each 33

10 95% and 65% harmonic mean (HM) home range sizes of
individual fox squirrels 34

11 Eveness of fox squirrel home range use as described by
ratios of 65% to 95% HM home range sizes 42

12 Summary of number of nests used by fox squirrels 47

13 Summary of percent of fox squirrel locations in a nest 50





















LIST OF FIGURES

Figure Page

1 Distribution of fox squirrels in the southeastern 2
United States

2 Location of the squirrel study area, Ordway Preserve, 8
Putnam County, FL

3 Location of the turkey oak study sites on the Citrus
Tract, Withlacoochee State Forest, Citrus Co., FL 10

4 1983 and 1984 longleaf pine cone and turkey oak acorn
production 25

5 Tracking session dates and seasonal events of
importance to fox squirrels 31

6 Harmonic mean home ranges: tracking session #1 35

7 Harmonic mean home ranges: tracking session #2 36

8 Harmonic mean home ranges: tracking session #3 37

9 Harmonic mean home ranges: tracking session #4 38

10 Harmonic mean home ranges: tracking session #5 39

11 Harmonic mean home ranges: tracking session #6 40

12 Harmonic mean home ranges: tracking sessions 4-6 43

13 Three-dimensional plot of all squirrels' use of the
study area 44

14 Three-dimensional plots of of squirrel home range use
in tracking sessions 4-6 45

15 Air temperature and percent of squirrel locations
in a nest by tracking session 51

vi










16 Mean percent of all squirrel locations in a nest by
tracking period and session 52

17 Frequency and diameter of turkey oaks containing nests
compared with randomly selected turkey oaks in ecotone
and upland 55

















Abstract of a Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science

FOX SQUIRREL HOME RANGE AND MAST CROPS IN FLORIDA

By

Angela Torres Kantola

August 1986

Chairman: Dr. Stephen R. Humphrey
Major Department: Forest Resources and Conservation

Home ranges, nest use, and primary food resources of Sherman's fox

squirrel (Sciurus niger shermani) were studied on the University of

Florida's Katharine Ordway Research Preserve in Putnam County, Florida.

Sherman's fox squirrel is a distinctive subpopulation with a small

geographic range which is declining in Florida due to habitat loss.

To understand production of its primary food resources, seed

production of longleaf pines (Pinus palustris) and turkey oaks (Quercus

laevis) was monitored for two years on contrasting sites of high

(ecotone) and low (upland) productivity. Mast production varied by

site, tree, year, and tree size. Production was higher in the ecotone,

significantly so in turkey oaks. In the second year, the turkey oak

acorn crop failed entirely.

Patchiness of these primary food resources likely explains the very

large home range size of this animal. Six fox squirrels were

radio-collared and tracked for varying lengths of time over a one-year

viii









period. Home range size was significantly greater in males than in

females. Home range size, position, and intensity of use were probably

affected not only by sex, but also by resource abundance, reproductive

season, and weather factors.

Squirrels used a calculated average of 30 nests/year, mostly

"leaf-nests" as opposed to tree cavities. More time was spent in the

nest during cold and very wet weather, indicating decreased activity

during these times.
2
Squirrel density was estimated to be roughly 12/km Nest counts

appeared to provide a reliable estimate of this density on the squirrel

study area and are recommended for testing in other areas of the

squirrels' range.

Habitat management is of primary importance to the survival of

Sherman's fox squirrel. Preservation and maintenance of natural, mature

longleaf pine forests is needed for successful management.





Chairman















INTRODUCTION


Sherman's fox squirrel, (Sciurus niger shermani) inhabits the

longleaf pine/turkey oak sandhills of the northern 2/3 of Florida's

peninsula and is one of three subspecies of fox squirrel in Florida

(Moore 1956; Fig. 1). The two others are S. n. niger, ranging from the

panhandle to southern Virginia (Hall 1981), and the endangered big

cypress fox squirrel, S. n. avicennia, isolated in southwestern Florida

(Williams and Humphrey 1979). S. n. shermani and S. n. niger are part

of a unique group of fox squirrels of the southeastern coastal plain

(Weigl et al., in press). The southeastern fox squirrels are the

largest and most variably colored tree squirrels in the western

hemisphere (Nowak and Paradiso 1983).

Southeastern fox squirrels have long been recognized as primarily

associated with mature, fire-maintained pine forests (Allen 1871,

Maynard 1872, Chapman 1894, Cory 1896). Now, however, large-scale

forest cutting, conversion to single-stand, short-rotation forestry, and

other land uses have caused a decline in the populations of these

squirrels. While habitat loss is the major reason for decline, Harper

(1927), Moore (1953 and 1954), and J. Reinman (pers. comm.) have

suggested that hunting also may be detrimental to local populations

under certain conditions.

Sherman's fox squirrel is currently under review by the U.S. Fish

and Wildlife Service for listing under the Endangered Species Act as

1





















































S. N. AVICENNIAi
-a -i


Distribution of fox squirrels in the southeastern
United States. Relic populations and midwestern
subspecies within the range of the map are not shown.


Figure 1.







3

threatened or endangered. It has been placed in Category Two: species

known to be subject to some threat of extinction but for which more data

are needed before a status designation can be made. Based on the trend

of habitat loss, the state of Florida has listed Sherman's fox squirrel

as threatened. However, hunting is still permitted in recognition that

the practice is traditional and not the primary cause of threat.

Wise management of this threatened squirrel requires a more

thorough understanding of the animal's habitat requirements. Toward

this end, the objectives of this study were to determine fox squirrel

home range size, habitat, and nest use, and to monitor mast production

of primary food resources on contrasting sites of high and low

productivity.















STUDY ANIMAL


The only technical literature on Sherman's fox squirrel is a

natural history study by Moore (1957). (More recent studies in North

Carolina (Weigl et al., in press) and Georgia (Hilliard 1979) have

addressed the ecology of S. n. niger.) Contrary to the predictions of

Bergmann's rule, Sherman's is the largest fox squirrel in North America.

Adults weigh just over 1 kg and average 650 mm in length. Pelage color

varies from all-black to all-tan color morphs; 1/16 are all black, 6/16

evenly divided between black over tan and tan over black, and 9/16 are

all tan.

Moore (1957) describes these squirrels as somewhat territorial

with a fairly large home range size. In 1946 he counted eight adult fox

squirrels on his 21-ha study area (described as optimum habitat).

However, he thought this density (38 squirrels/km2) was atypical, and

likely to be much lower in other, unprotected parts of northern Florida.

Investigators on the Katherine Ordway Research Preserve, Putnam Co., FL

have estimated current fox squirrel densities there to be only

8.4-15/km2 (Humphrey et al. 1985, M. Sunquist, pers. comm.).

Principal predators appear to be the bald eagle, red-tailed hawk,

and man (Moore 1957). However, Sherman's fox squirrel exhibits several

behaviors that may help it avoid predation. Individuals apparently

maintain a large number of nests which may provide protection from

predation. Moore (1957) reported several instances of pursued fox

4







5

squirrels taking refuge below ground in gopher tortoise (Gopherus

polphemus) burrows. They also will "hide" in the plume of needles on an

apical twig of a longleaf pine in such a way that the twig bends over

horizontally beneath them and conceals them from predators below. When

pursued, they may leap from tree to tree or jump to the ground from

heights up to 15 m, and escape on the ground where they have been timed

at speeds of 24 kph (Moore 1957).

Longleaf pine (Pinus palustris) seeds and turkey oak (Quercus

laevis) acorns are the squirrel's primary food resources. Fungi,

fruits, insects, and staminate cones may be eaten when pine cones and

acorns are unavailable. Two breeding seasons occur each year and

natality is relatively low (2.3 young per litter) compared to 2.5-3.2

for the much-studied midwestern fox squirrel, S. n. rufiventer. The

lower reproductive rates of S. n. shermani probably are related to the

nutrient-poor Florida sands, which provide less energy to consumers than

the richer soils of the midwest. Several authors have found squirrel

reproductive rates to vary with mast production (Chesemore 1975, Havera

and Nixon 1980, Weigl et al, in press).















STUDY AREA


The study was conducted on the University of Florida's Ordway

Preserve in Putnam County. Roughly 1/3 of this 37-km2 preserve is

longleaf pine/turkey oak sandhill, the typical habitat of Sherman's fox

squirrel. Historically, the longleaf pines of the area have been tapped

for turpentine, subjected to annual burning, and removed by logging.

This reduction in pine density has led to an increase in turkey oak

density. Current densities are reported at 59 pines and 175 oaks >3 cm

diameter-at-breast-height (dbh) per hectare (Humphrey et al. 1985).

The sandhill habitat grades from "upland" downslope into "ecotone".

Upland occurs on dry hilltops of low productivity. Here longleaf pines

and turkey oaks create a fairly open canopy over a moderate amount of

herbaceous vegetation dominated by pineland-threeawn (Aristida stricta).

Similar but denser and more varied vegetation occurs on the lower, more

productive slopes of ecotone, where the predominant longleaf pines and

turkey oaks are interspersed with sand post oak (Quercus stellata var.

margaretta), live oak (Q. virginiana), laurel oak (Q. laurifolia), and

bluejack oak (Q. incana).

The squirrel study area was a sandhill centered in the Ford and AQ

(Anderson Cue) Areas of the Ordway Preserve (Fig. 2). The central

upland graded into ecotone on much of the perimeter. Numbered grid

stakes were placed at 100-m intervals over a 91 ha to facilitate mapping

of animal locations.




































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METHODS


Mast Monitoring



Turkey Oaks

Three data sets on mast production by turkey oaks were analyzed.

First, to understand the spatial, temporal, and tree-to-tree variation

in acorn numbers, I analyzed data collected between 1962 and 1973 by

S. L. Beckwith and R. W. Umber on the "Citrus Tract" in the

Withlacoochee State Forest near Inverness, Florida (Fig. 3). In the

fall of each year they made a complete count of all turkey oak acorns on

the trees and on the ground below the canopy. Trees were sampled on two

260-ha blocks each containing three 8-ha replicates divided into 2-ha

quadrants. Each quadrant ideally contained four sample trees chosen by

the point-center quarter method. Due to low tree density and natural

mortality, not all quadrants contained four trees throughout the study

(Umber 1975). Acorn production was not monitored in 1971 or 1972 and

was only monitored on Block 2 in 1962. In 1963 Block 1 contained 38

sample trees and Block 2 contained 45. By 1973, 33 of the sample trees

remained in Block 1 and 41 remained in Block 2. The results of this

analysis were used to choose sampling procedures and test analytical

methods for the Ordway Preserve studies of turkey oaks.















METHODS


Mast Monitoring



Turkey Oaks

Three data sets on mast production by turkey oaks were analyzed.

First, to understand the spatial, temporal, and tree-to-tree variation

in acorn numbers, I analyzed data collected between 1962 and 1973 by

S. L. Beckwith and R. W. Umber on the "Citrus Tract" in the

Withlacoochee State Forest near Inverness, Florida (Fig. 3). In the

fall of each year they made a complete count of all turkey oak acorns on

the trees and on the ground below the canopy. Trees were sampled on two

260-ha blocks each containing three 8-ha replicates divided into 2-ha

quadrants. Each quadrant ideally contained four sample trees chosen by

the point-center quarter method. Due to low tree density and natural

mortality, not all quadrants contained four trees throughout the study

(Umber 1975). Acorn production was not monitored in 1971 or 1972 and

was only monitored on Block 2 in 1962. In 1963 Block 1 contained 38

sample trees and Block 2 contained 45. By 1973, 33 of the sample trees

remained in Block 1 and 41 remained in Block 2. The results of this

analysis were used to choose sampling procedures and test analytical

methods for the Ordway Preserve studies of turkey oaks.





































0 2 4
I II
KM


Figure 3.


INVERNESS
*


Location of turkey oak study sites on the Citrus Tract,
Withlacoochee State Forest, Citrus Co., FL.










To learn whether mast production varied with elevation on the

Ordway Preserve, in the fall of 1983 I counted acorns on 33 trees on a

gradient running from the western hilltop down to the margin of Anderson

Cue Lake. Eleven sets of three trees each were selected at 25-m

intervals and all acorns on these trees and on the ground below them

were counted.

Finally, to monitor mast production on and near the radiotracking

site through the study, I counted acorns in the fall of 1983 and 1984 on

six areas (three ecotone and three upland) within the Ordway Preserve.

Each area contained three, 10-tree replicates, for a total of 180 trees.

The upland areas were designated ECUE, having replicates in the AQ and

Fox Pond Areas, (refer to Fig. 2), WCUE in the AQ and Suggs Areas, and

STUDYU in the AQ Area. The ecotone areas were STUDYE in the Ford Area,

SWCOR in the Rowan Southside Area, and SMITH in the Smith Lake Area.

Acorns were counted in late October and early November of 1983

and 1984 after most had fallen from the tree. Where production was

judged to be moderate to heavy, an area estimated to contain one-quarter

of the groundfall was counted, multiplied by four, and added to any

acorns seen on the tree (using 7x binoculars) to arrive at the total

count. Since this method did not account for acorns removed by animals

or distinguish rotten (infested) or immature acorns, it was intended

only as an index of production over each area. Such an index cannot

accurately describe available energy in terms of total kg of acorns, but

it is adequate for comparison of production among areas.

Longleaf Pines

Longleaf pine cone production was monitored on five areas (two

ecotone and three upland). Pine cone production was twice as variable








12

as acorn production, so each area contained three, 20-tree replicates

for a total of 300 trees monitored. Replicates were in the same general

areas as those of turkey oaks, except in the SMITH area where no pines

were monitored. Pine cones were counted in the winters of 1983 and 1984

after most had fallen to the ground or been cut by squirrels leaving the

cores beneath the tree. Counts made using 7x binoculars in late summer

when most cones remained on the tree proved too inaccurate for use.

To obtain seed counts, pine cones were removed from selected trees

in each area using a tree pruner or a semi-automatic .22-caliber rifle

with telescopic sight. Hollow-point bullets were found to be more

effective in obtaining cones than other bullets. The number of rounds

required to remove each cone depended on position of the cone on the

tree, shooter accuracy, and shooter fatigue, but 8 rounds per cone was

typical.



Nest Counts



Squirrel nests were counted on ten 1-ha plots each in ecotone and

upland portions of the squirrel study area. Counts were made when nests

were most visible in December 1984 and January 1985, after most of the

leaves had fallen from the deciduous oaks. The length of each hectare

was walked in strips 10-20 m wide (depending on tree density) until the

entire area had been checked. At each nest, tree species, dbh, and nest

composition (twigs, leaves, and/or Spanish moss) were recorded. Tree

cavities also were noted but not used in analysis.










Capture and Handling



Southeastern fox squirrels are much more difficult to trap than

midwestern subspecies (Weigl et al., in press). Squirrels were captured

in No. 104 Tomahawk double-door cage live traps. Animals were

particularly difficult to trap when their food resources were abundant.

Trapping effort was nearly continual but most intense in seasons of low

food abundance.

Groups of 2-20 traps were placed throughout the study area at sites

where squirrels were seen repeatedly. Usually, traps were positioned

beneath trees that contained squirrel nests or appeared to be used by

squirrels for feeding or caching. During warm weather, traps were

covered with Spanish moss (Tillandsia usneoides) to provide shade for

trapped animals. Traps were normally set shortly after sunrise, checked

periodically throughout the day, and closed before dusk. Occasionally,

traps were left open overnight.

Traps were baited with pecans. Peanut butter was later added as a

base to make removal of the pecans difficult and successful trapping

more likely. Late in the study, instant-bonding glue was used for this

purpose, but its success could not be determined since food was abundant

at.this time and only one squirrel was caught. A liquid attractant,

"Squirrel Scent" (Buck Stop Lure Co., Stanton, Mich.), was placed on and

around traps in an effort to increase trapping success. Before trapping

began, traps were prebaited (baited and wired open) for several weeks to

habituate the squirrels to obtaining food from them. The prebaiting

effect was continued throughout the study by wiring open baited traps at

the end of each trapping session.







14

Usually a captured squirrel was transported to an enclosed room in

a nearby pole barn for radio-collaring. The animal was transferred from

the trap to a wooden drugging box and restricted to one end. Vapor from

several drops of Fluothane (Fort Dodge Laboratories Inc., Fort Dodge,

Iowa) on cotton was administered through the top of the box and the

animal was observed through a plexiglass panel. Within a few minutes,

the squirrel could safely be removed with gloved hands and administered

10-15 mg Ketaset (Veterinary Products, Bristol Laboratories, Syracuse,

N.Y.) to further anesthetize it. Booster doses of 5-10 mg Ketaset and

Fluothane vapor were administered as needed. Physical restraint also

was required since the anesthesia did not fully immobilize the animal.

Standard body measurements were made, as well as notes regarding

reproductive and physical condition, wounds, ectoparasites, and pelage

color. The animal was ear-tagged (#1, style 4-1005, National Band and

Tag Co., Newport, Ky.) and then fitted with either a radio or

identifying collar. Radio collars were closed with nuts and bolts

coated with locking compound. Solar radio collar closures were secured

with shrink tubing heated with a soldering iron held 1 cm from the

collar. Radio collars also were wrapped with colored vinyl tape to aid

in visual identification. Two squirrels not radio-collared were fitted

with number 13 ball-chain collars with identifying colored beads.

Finally, wounds (typically nose wounds from the animal "fighting"

the trap) were medicated, and the squirrel was weighed and returned to

the drugging box for holding. Recovery took 30-60 min, after which the

squirrel was transported back to the capture site and released. Animals

captured near dusk usually were held overnight and released the

following morning.







15

Methods of capture and handling were successfully tested on an *

animal living distant from the squirrel study area in March 1984.

Subsequently, five males from the squirrel study area were collared

between 28 March and 3 June 1984. Radio collars were placed on four of

these squirrels (M1-M4). The fifth received an identifying bead collar

but was never re-sighted. M1 and M2 were tracked throughout the study.

Ml's collar came off after 38 days and was replaced four days later.

Both Ml and M2 received solar radio collars on 2 December. M3 was

tracked through 27 October after which his second collar presumably

slipped off (the collar was found still functioning and fastened in a

loop). M3 was never positively identified again and efforts to re-trap

him were unsuccessful. M4 was tracked through 8 September and was found

badly decomposed with collar intact and radio functioning on 14

September. Two females (Fl and F2) were captured in November, after

extensive trapping efforts. Both were tracked through the end of the

study in May 1985. Only three other fox squirrels (all males) were

caught during the study. One apparently died from heat while in the

trap, and a second from unknown causes while under anesthesia. A third

squirrel (male) was caught during an attempt to re-trap Fl and F2 after

the completion of the study.



Telemetry and Related Equipment



Equipment

Two types of radio collars were used. The first was a 2-stage RF

whip antenna transmitter (Cedar Creek Bioelectronics, Bethel, Minn.)

weighing 36 g with a 2/3 A 3 volt lithium battery having an estimated







16

life of 6 months. Eight of these collars were deployed. Three remained

on the animal longer than 6 months and continued to transmit signals.

The second type of radio collar used was a SM-1 solar and nickel-cadmium

(NiCad) battery powered transmitter (AVM Instruments Co., Livermore,

Calif.) weighing 14 g and having an estimated working life of 5 years

with a 60 mA/h 1.2 volt NiCad battery and five 5-mm silicon solar cells.

Two of these collars were placed on animals in December 1984 and were

functioning well at the end of the formal study period in May 1985. The

animals were tracked occasionally until November 1985, after which they

could not be relocated.

The tracking system consisted of a 36-band AVM LA-12 receiver tuned

to 164 MHz, a hand-held RA-2AD yagi antenna (Telonics Inc., Mesa Ariz.)

and lightweight headphones. A vehicle-mounted RA-5A whip antenna also

was used.

Telemetry

The rolling topography of the study area and the need for precise

animal locations rendered triangulation inappropriate for determining

squirrel locations. Instead, a signal was followed until the squirrel

was located visually or precisely by signal strength and direction.

Exact location was recorded by measuring azimuth and estimating distance

of the animal from the nearest numbered grid stake. Locations were

later plotted to the nearest 25 m2 and assigned x and y coordinates.

Time, position (in a tree, nest, or on the ground), and any activity

also were recorded at each location. Nest trees used by each squirrel

were marked and numbered. Animals apparently observed the researcher

and altered their behavior before they could be seen, so behavioral

notes were rare.







17

Squirrels were monitored regularly from June 1984 through May 1985.

Radiotelemetry was divided into six tracking sessions each consisting of

four 2-day (usually consecutive) periods. The four periods in each

session usually were one week apart and spanned a total of 4-6 weeks.

Tracking sessions were separated by 4 weeks of no tracking. To ensure

independence of observations and allow the squirrels to resume normal

behavior after the researcher's intrusions, animals were located once

every 2-4 hours, depending on day length. For each day of tracking,

daylight was divided into three equal periods, and squirrels were

located once each period. To thoroughly sample the day and help

document nest use, squirrels were located early in each period the first

day of tracking and late in each period the second day.



Statistical Methods



Comparisons of mast production data between areas, replicates,

trees, tree size, and year were made using analysis of variance (PROC

GLM of the Statistical Analysis System, Ray 1982). Since many trees

produced no mast, data were transformed by adding one to the count and

computing the natural log.

Home range size was calculated using an IBM microcomputer and the

McPAAL program for the analysis of animal locations (Smithsonian

Institution). Three measures were calculated: 1) the minimum area

(Mohr 1947), also called the minimum convex polygon (MCP), 2) the 95%

probability ellipse (Jennrich and Turner 1969), and 3) the harmonic mean

(HM) (Dixon and Chapman 1980). The first two measures are presented to







18

make the results comparable with other studies. Discussion will focus

primarily on the HM.

Based upon the harmonic mean of an areal distribution, the HM plots

contours encompassing areas of equal activity, or frequency of

occurrence, of an animal within its home range. The HM provides insight

into the intensity of use of the home range, is not as sensitive to

sample size as the MCP, and (unlike the 95% probability ellipse) does

not assume a bivariate normal distribution of animal locations. The

contour encompassing 95% of an animal's locations (95% HM) is here

considered to exclude unusual movements and to represent whole home

range, while the 65% HM approximates a core area of use within the

range.

Another important aspect of home range is the intensity, or eveness

of use. Eveness can be represented by the ratio of the 65% HM to the

95% HM. As this ratio approaches one, the squirrel's eveness of home

range use increases. A three-dimensional representation of squirrel

home range use was produced using PROC G3D in SAS/GRAPH of the

Statistical Analysis System (SAS Institute 1981).

Home ranges were analyzed by both individual and combined

radiotracking sessions. Data from incomplete tracking sessions (Session

2 for M4 and Session 3 for M3 and Fl) were not used in calculating home

range size or eveness of use. T-tests (PROC TTEST of the Statistical

Analysis System, Ray 1982) were used to compare home range size and

eveness of use between the sexes as well as nest counts between ecotone

and upland. The coefficient of determination (Sokal and Rohlf 1981) was

used to measure the correlation between air temperature and percent of

locations squirrels were in a nest.















RESULTS


Mast Production



Turkey Oaks

On the Citrus Tract, the number of acorns produced per tree varied

greatly over both time and location. Umber (1975) reported a high of

49.1 mean acorns/tree in 1965 and a low of 1.0 in 1969. Block 2

consistently outproduced Block 1 with four years of good mast yields to

only one in Block 1, but no biological explanation was offered. The two

blocks were approximately 1.6 km apart, and although different burning

schedules may have been used, no record of burning was kept. Further

analysis by year revealed that acorn production varied between blocks in

all but 1966 and 1967, among replicates in 1963 and 1966, and by dbh

only in 1968. Also by year, no block x replicate or quadrant (nested in

block x replicate) effects were shown. Combined-year analysis (Table 1)

showed variation among years and also among quadrants (nested in block x

replicate). Because the quadrant effect was inconsistent among

replicates and blocks, these did not have significant effects when

quadrants were used as an error term. The effect of tree size (dbh) on

acorn production was insignificant.

On the Ordway Preserve slope (Table 2), turkey oak production

varied between treatments (top and slope) (P < 0.05) and by dbh

(P < 0.01). Turkey oaks on the hilltop produced a mean of 19.9 acorns,

19















RESULTS


Mast Production



Turkey Oaks

On the Citrus Tract, the number of acorns produced per tree varied

greatly over both time and location. Umber (1975) reported a high of

49.1 mean acorns/tree in 1965 and a low of 1.0 in 1969. Block 2

consistently outproduced Block 1 with four years of good mast yields to

only one in Block 1, but no biological explanation was offered. The two

blocks were approximately 1.6 km apart, and although different burning

schedules may have been used, no record of burning was kept. Further

analysis by year revealed that acorn production varied between blocks in

all but 1966 and 1967, among replicates in 1963 and 1966, and by dbh

only in 1968. Also by year, no block x replicate or quadrant (nested in

block x replicate) effects were shown. Combined-year analysis (Table 1)

showed variation among years and also among quadrants (nested in block x

replicate). Because the quadrant effect was inconsistent among

replicates and blocks, these did not have significant effects when

quadrants were used as an error term. The effect of tree size (dbh) on

acorn production was insignificant.

On the Ordway Preserve slope (Table 2), turkey oak production

varied between treatments (top and slope) (P < 0.05) and by dbh

(P < 0.01). Turkey oaks on the hilltop produced a mean of 19.9 acorns,

19



















Table 1. Summary of analysis of variance on transformed


counts of turkey oak
Citrus Co., FL.


acorns on the Citrus Tract,


Source Of SS F PR > F


Dbh
Block (B)
Replicate (R)
B xR
Quadrant (Q) [B x R]
Tree [B x R x Q]
Year (Y)
B xY
RxY
BxRxY
Q x Y [B x R]


Tests of hypotheses using Type
error term:


III MS for Q [B x R] as an


1.81
2.82


B xR


0.1949
0.0863


Tests of hypotheses using Type III MS for Q
an error term:


B x Y
BxY
RxY
B x Rx Y


x Y [B x R] as


47.19
19.85
1.51
1.40


0.0001
0.0001
0.0918
0.1476


0.20
9.88
30.69
3.77
98.10
322.52
332.12
124.15
21.32
17.54
118.08


0.25
12.11
18.82
2.31
6.68
6.59
45.26
19.03
1.45
1.34
0.96


0.6191
0.0005
0.0001
0.1000
0.0001
0.0001
0.0001
0.0001
0.1026
0.1654
0.6148






















Table 2. Turkey oak acorn production on the
Ordway slope.


x Acorns/Tree

46.00

31.00

6.00

14.33

2.33

39.67

66.67

16.00

22.33

19.67

19.33


Treatment

Top

Top

Top

Top

Top

Slope

Slope

Slope

Slope

Slope

Slope


Set

1

2

3

4

5

6

7

8

9

10

11







22

compared with 30.6 on the slope. This difference may be correlated with

a greater availability of soil nutrients and water at lower elevations,

but these factors were not measured.

The 180 turkey oaks of the six sampled areas on the Ordway Preserve

yielded a good crop in 1983 (i/tree = 58.5) but almost no acorns were

produced in 1984 (T = 0.18) (Tables 3 and 4, Fig. 4). In 1983

production varied by dbh, among areas, and replicates within area. A

contrast of upland versus ecotone confirmed a variation in production

between these habitat types.

A separate analysis of the two areas on the squirrel study area

showed that acorn production did not differ between areas when

replicates within area were used as an error term. Without the error

term, significant variation was shown. This difference occurs because

the replicates did not vary consistently between areas.

Longleaf Pines

Longleaf pine cone production also was higher in 1983 (x = 27.3)

than in 1984 (7 = 14.0) (Tables 5 and 6, Fig. 4). Analysis of

combined-year data revealed that cone production varied significantly

between years and by dbh. Nested and interaction effects differed for

replicates within areas, trees within areas x replicates, and replicates

x years within areas. Using replicates within areas as an error term,

variation in cone production did not differ among areas. Without the

error term an area effect was shown, so replicates did not vary

consistently among areas. Likewise, areas x year did not differ when

replicates x year within areas were used as an error term. Production

did vary among areas x year without this error term, so replicates did

not vary consistently among areas x year.

























Table 3. Turkey oak acorn production on six areas of the Ordway
Preserve.


1983
Acorns/Tree

12.57

7.93

67.47

29.32


120.87

104.90

37.03

87.60


1984
Acorns/Tree

0.25

-0-

-0-

0.08


-0-

0.70

0.67

0.26


Total
Acorns/Tree/Year

6.62

4.33

34.90

15.28


61.46

52.80

18.55

44.27


Treatment

Upland

Upland

Upland

7 Upland


Ecotone

Ecotone

Ecotone

T Ecotone


Area

ECUE

WCUE

STUDY


STUDY

SWCOR

SMITH


--




















Table 4. Summary of analysis of variance on transformed
counts of turkey oak acorns on six areas of the
Ordway Preserve and on two of those areas
within the squirrel study area (1983).



Source Of SS F PR > F


All Areas

Dbh
Area (A)
Replicate (R) [A]


41.02
146.10
55.66


33.18
23.64
3.75


0.0001
0.0001
0.0001


Tests of hypotheses using
error term:
A
Contrast:
Upland vs. ecotone 1


Type III MS for R [A] as an


60.83


6.30

13.11


0.0043

0.0035


Squirrel Study Site


14.63
4.63
28.61


R [A]


12.57
3.98
6.14


0.0008
0.0512
0.0004


Test of hypothesis using Type III MS for R [A] as an
error term:
A 0.65 0.4661


























140-

120-

100-

80-

60-

40-


20-4


83 84 83 84 83 84
SMITH SWCOR STUDY
-- ECOTONE


~d1


rJL


83 84 83 84 83 84
STUDY ECUE WCUE
UPLAND


REPLICATE PLOT WITHIN AREA BY YEAR


Figure 4.


1983 and 1984 longleaf pine cone and turkey oak acorn
production. In 1984, no acorns were found on the WCUE,
STUDYU, or STUDYE areas and less than one acorn/tree was
found on the ECUE, SWCOR, and SMITH areas. No samples
of longleaf cones were taken at SMITH.


OA


d


























Table 5. Longleaf pine cone production on five areas of the Ordway
Preserve.


1983
Cones/Tree

20.85

24.82

27.98

24.55


1984
Cones/Tree

14.37

13.73

13.93

14.01


Total
Cones/Tree/Year

17.61

19.28

21.02

19.30


Ecotone

Ecotone

7 Ecotone


Treatment

Upland

Upland

Upland

7 Upland


Area

ECUE

WCUE

STUDY


STUDY

SWCOR


44.65

17.98

31.32


17.17

11.03

14.10


31.03

14.51

22.77


---


--


--












Table 6. Summary of analysis of variance on transformed
counts of longleaf pine cones on five areas of
the Ordway Preserve and on two of those areas
within the squirrel study area (1983 and 1984).



Source Df SS F PR > F

All areas

Dbh 1 0.39 0.64 0.4249
Area (A) 4 7.64 3.09 0.0164
Replicate (R) [A] 10 45.76 7.40 0.0001
Tree [A x R] 286 614.58 3.48 0.0001
Year (Y) 1 41.93 67.84 0.0001
A x Y 4 9.09 3.68 0.0062
R x Y [A] 10 19.33 3.13 0.0008

Test of hypothesis using Type III MS for R [A] as an
error term:
A 0.42 0.7926

Tests of hypotheses using Type III MS for R x Y [A] as an
error term:
Y 21.69 0.0009
A x Y 1.18 0.3783

Squirrel Study Site

Dbh 1
A 1 0.04 0.07 0.7985
R [A] 4 24.03 10.38 0.0001
Tree [A x R] 113 297.55 4.55 0.0001
Y 1 33.52 57.94 0.0001
A x Y 1 1.57 2.71 0.1026
R x Y [A] 4 6.45 2.79 0.0298

Test of hypothesis using Type III MS for R [A] as an
error term:
A 0.01 0.9405

Tests of hypotheses using Type III MS for R x Y [A] as an
error term:
Y 20.78 0.0103
A x Y 0.97 0.3800







28

A separate analysis of the two sampling areas on the squirrel study

area showed no variation in cone production between areas, or areas x

year. Otherwise, variation within the squirrel study area reflected

that of all areas combined.

Due to difficulties experienced with storing and opening collected

pine cones, few data were collected from these. However, most of the

cones that were examined contained <50% viable seeds.

Seed Production and Temperature

Both longleaf pine and turkey oak seeds require two growing seasons

to mature. Seed production in pines may be adversely affected by

unusually low temperatures or drought during flower development and

immediately prior to pollination (in early spring) (Schopmeyer 1974,

Olson and Boyce 1971). Table 7 summarizes April temperatures for the

area from 1982-1985. Overall, temperatures were lower in April 1983

than any of the other years, and may have contributed significantly to

the turkey oak acorn failure and lower pine cone production in 1984.

Relationship of Squirrels to Food Resources

The capture dates, weights, and body measurements listed in Table 8

provide insight to the squirrels' relationships with their primary food

resources. Of squirrels caught more than once, Ml was at his lowest

weight in early June, at the end of both the summer breeding season

(during which he was sexually mature and active) and the late

spring/early summer period of low food abundance (Fig. 5). M3 was at

his greatest weight in early October, towards the end of the pine

cone-cutting season, but prior to the turkey oak acorn season, which

failed in 1984. Both M1 and M2 had enlarged testes and were seen in

mating chases during the 1984 summer breeding season. However,




























Table 7. April temperatures ( C), 1982-1985, Gainesville.


x Monthly Departure
Temp. From Normal

21 -0.1

18.1 -2.79

19.8 -1.08

20.8 -0.09


7 Min.
Temp.

14.5

10.4

12.4

13.6


Monthly Low # of Days With
and Date Min. Temp <7 C

6.1 12 2

4.4 17 11

5.6 6 4

2.8 3 5


Year

1982

1983

1984

1985




























t In CL C I o I C
-4 -1 -4 C) --4 -4


I C\J Y)
-4 -4


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E




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c,
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S
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LO O C) rm O O 101 O Cj
C\1 m I Io l o u ) r" i O TO C) -4
LO 10) (.0 1.0 t.0 (D0 '.0 t0 Lo0 LO 10 p











































BREEDING
SEASONS


YOUNG
IN NEST


LONGLEAF PINE
CONES AVAILABLE


TURKEY OAK
ACORNS AVAILABLE


1984-a8
TRACKING SESSIONS


2 3
...... ,........


JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY


Tracking-session dates and seasonal events of
importance to Sherman's fox squirrel.


4
...""""".


5 6
*..... .......


Figure 5.


1
"""o""







32

following the turkey oak mast failure in that fall, neither had enlarged

testes when captured in December nor were they observed in mating chases

during what should have been the winter breeding season. In fact, none

of the highly visible mating chases were seen by this investigator or

others questioned during this season in 1984. Following an apparently

good turkey oak acorn crop in 1985, however, M2 and five other squirrels

were observed in a mating chase on 24 November (S. Brand pers. comm.).

These data suggest that the squirrels may respond to mast failures by

not breeding, thereby conserving energy.





Home Range



Tracking-session dates and number of locations/squirrel in each

session are listed in Table 9. Figure 5 shows the tracking-session

dates in relation to important seasonal events and is a useful reference

when comparing home range and nest use between sessions.

The 95% and 65% HM contours for each squirrel in each radiotracking

session are shown in Table 10 and Figures 6-11. A paired-difference

t-test showed that mean squirrel home range size for individual tracking

sessions was significantly larger as measured by the 95% HM than as

measured by the MCP (P < 0.01). Additionally, the 95% HM measured a

greater percentage of cumulative home range size per tracking session

(X = 63.17%) than did the MCP (x = 47.58%).

Mean cumulative home range size (95% HM) was 42.8 ha for males and

16.70 ha for females. These measures include all squirrels, so the

number of locations/squirrel and sessions tracked are not constant. Two

























Table 9. Dates of radiotracking sessions and number
of locations/squirrel in each session.


Dates

17Jun84-22Ju184

24Aug84-15Sep84

190ct84-17Nov84

14Dec84-19Jan85

22Feb85-16Mar85

19Apr85-12May85


No.
M1

21

24

24

23

24

24

140


locations/squirrel
M3 M4 Fl F2

22 21 0 0

24 18* 0 0

12* 0 12* 0

0 0 23 23

0 0 24 24

0 0 24 24

58 39 83 71


*Squirrel not tracked through entire session.


Tracking

1

2

3

4

5

6

Total


---


---



















LIt
Ii-


C.)


O

tO



CO


CM -d- 0 0




I 1 2 1 .










C C\JY )
-4O -4

N N d


I 1 1 1 1 1 2 2 2 I 2 2 I 2 2





2 1 1 1 1 1 2 2 2 I I 2 2 2 2


Ct)


*-*



n
hO



* .
0"'- i


C4t

0)



to


ro


ko









0n.



t0O







LO












LOT
Vi






















20)













S- 1

0)
0. '







2: .


tL CM CO





0m -4





-o 00 -0


2- q -2 rI




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T-11 1 1 1 1 *
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-4 C l-4 .-4 .-4 r -4 r .-4 -4 r-4 -4 r.-4- .-I1 -_




.-4 (X oXi 00 i LOO .0 M N -4 00 r to C:) td m-





UNNOMOO 000~~0000000
0a) r M) -4 0Co r) o .-4 1r-4 -zM- o ct) 0.) to to -- tO 1- .4- N- cm
C C C m 0) CD 1-4 Ct) co to to t M to CD to M tO



C(i rN tO to O to to .-4 tO (Y) q- r-4 to tO -1 '-A C -4 .-4 CD .)





Co to m mOLs-IC.-) m m .: t LO-C MMO' L-ir-d to O to r-I (n









s t I Ct) C** n to CY) :d- t o-t o td-O to LO No- o
,-I Ir-4 -4 i-f C 2 C2 M O m e L















































(17 JUN-22JUL)


Figure 6.


Harmonic mean home ranges:
tracking session #1. Dashed
lines connect outlying
portions of the home range.















































(24 AUG-15 SEP)


Figure 7.


Harmonic mean home ranges:
tracking session #2.














































(19 OCT-17 NOV)


Figure 8. Harmonic mean home ranges:
tracking session #3.














































(14 DEC-19 JAN)


Figure 9.


Harmonic mean home ranges:
tracking session #4.














































(22 FEB-16 MAR)


Figure 10.


Harmonic mean home ranges:
tracking session #5














































(19 APR-12 MAY)


Figure 11.


Harmonic mean home ranges:
tracking session #6.









males (Ml and M2) and two females (F1 and F2) were tracked through

Sessions 4-6. For this period, the males had a significantly larger

mean home range (95% HM x = 31.91 ha, P < 0.01) and core area (65% HM

x = 8.45 ha, P < 0.05) per tracking session than the females (95% HM

x = 10.99 ha and 65% HM 7 = 2.95 ha). Mean cumulative home range and

core area for sessions 4-6 also were larger (P < 0.01) for the males

(95% HM 7 = 64.97 ha and 65% HM 7 = 12.79 ha) than for the females

(95% HM x = 16.7 ha and 65% HM = 5.68 ha).

The 65% to 95% eveness ratios are listed in Table 11 and can be

seen diagrammatically in the plots of the 95% and 65% HM contours in

Figures 6-11. Considering the great difference between male and female

home-range sizes, one might expect eveness of home-range use to be

greater in females than in males. While mean male (.30) and female

(.28) eveness ratios for tracking sessions 4,5,and 6 were not

significantly different (P > 0.10), cumulative (sessions 4-6) home-range

eveness (sessions 4 through 6) was greater (P = 0.0519) in females

(3 = .34) than in males (T = .20) (Fig. 12).

Three-dimensional diagrams of animal locations also can be used to

depict intensity of home range use. Cumulative use of the study area by

all of the tracked squirrels is shown three-dimensionally in Figure 13.

The X and Y axes represent the x,y grid coordinates and the Z axis

represents number of locations/25-ha grid cell. Squirrels' repeated use

of certain nests results in points very high on the Z axis. Location of

such nests is even more obvious in Figure 14 which shows the home range

use of Ml, M2, Fl, and F2 in sessions 4-6.

The effect of season on home-range size and eveness is difficult to

assess because only two squirrels were tracked for the entire study







42












Table 11. Eveness of fox squirrel home range use as described by ratios
of 65% HM to 95% HM home range size.



Tracking
Session(s) M1 M2 M3 M4 Fl F2 M F All

1 .14 .26 .44 .17 .25 -
2 .20 .19 .19 .19
3 .24 .37 .31 -
4 .13 .41 .19 .05 .27 .12 .19
5 .13 .35 .23 .47 .24 .35 .30
6 .31 .46 .36 .37 .38 .37 .38
1-2 .14 .28 .26 .23 -
1-3 .31 .35 .33 -
1-4 .42 .40 .41 -
1-5 .32 .40 .36 -
1-6 .26 .34 .30 -
2-3 .37 .36 .37 -
2-4 .41 .43 .42 -
2-5 .30 .31 .30 -
2-6 .38 .30 .34 -
3-4 .26 .44 .35 -
3-5 .17 .25 .21 -
3-6 .21 .25 .23 -
4-5 .18 .15 .21 .22 .17 .21 .19
4-6 .15 .25 .35 .33 .20 .34 .27
5-6 .25 .34 .42 .43 .29 .43 .36












































(14 DEC-12 MAY)


Figure 12.


Harmonic mean home ranges:
tracking sessions #4-6.











44




















i,

au



34-







-0
-II



-) O





OE
S-r-
0r- "

U) C
*- 0
r- I-
r- -0





0
o-

0


- 0
oE












I S- II
O
s- o


I- r-
rS- )
03







0- .
EI*
I II
1 4a>









r--


-C
01-


















TRACKING SESSION #4





















TRACKING SESSION #5













TRACKING SESSION *a


X (METERS)


Figure 14.


Three-dimensional plots of squirrel home range use in
tracking sessions 4-6. (Square=M1, balloon=M2, club=F1,
and cross=F2.)


Z *


Y (METERS)







46

period. Data in Table 7 indicate a pattern of increased home-range size

in sessions 2 and 3 from session 1. This may have been a response to

the peak of the pine cone-cutting season in session 2 and searches for

acorn-producing oaks in session 3. Individual differences rather than

general trends were prevalent in sessions 4, 5, and 6 for both males and

females. Eveness ratios in Table 9 provide little additional insight

into seasonal changes. The very low eveness ratio for M1 in session 4

does indicate that only a small part of this surprisingly large home

range was used frequently.



Nests



Each squirrel used several nests. Most were leaf nests, formed of

twigs, leaves, Spanish moss, and/or pine needles. Very few were cavity

nests in decaying turkey oaks. Nests were used by individual squirrels

an average of 2.65 times each. Most nests (49% of total) were used by a

squirrel only once. 17.3% nests were used twice, 12.5% were used three

times, 15.4% were used 4-7 times, and 5.8% were used 8-11 times.

Nest Numbers

Numbers of nests used are summarized in Table 12. Total number of

nests used by each squirrel varied from 9-28. Total number of nests

used by a squirrel in any one tracking session varied from 3-10

(x=5.76). With the exception of M4, the number of nests used by each

squirrel was relatively constant, as is shown by the mean number of

nests/tracking session and the ratio of total number of nests to number

of locations in Table 10. An average expected number of nests used by a

squirrel over a one-year period may be extrapolated from the latter


























Table 12. Summary of number of nests used by fox squirrels.


Individual

# Locations

# Complete
Tracking Session

Total # Nests Used

x Nests/Tracking
Session

# Nests: #Locations


Ml M2

140 138


6

21


4.67

.150


6

28


6.00

.203


M3

58


2

9


4.50

.138


M4

39


1

16


10.00

.410


Fl

83


3

19


6.67

.229


F2 x

71 88.17


3

11


6.00

.155


3.5

17.33


5.76

.214


---







48

figure in the following manner: since squirrels were tracked following

a schedule that would yield a maximum of 144 locations/squirrel/year,

the mean ratio of number of nests to number of locations (.214) is

multiplied by 144, resulting in an expected average of 30 nests/squirrel

over one year. This estimate may be too high if human disturbance by

radiotracking caused the animals to seek refuge in nests they would not

have ordinarily used. On the other hand, it is also possible that

squirrels use more nests than are estimated by a sample of 144

locations/year.

Nest Use Overlap

Some overlap did occur in the nests used. Nine nests (9.5% of all

nests) were used by two of the tracked squirrels. The first user died

before the second animal was located in two of these nests, and the

first animal had not been located in three of the nests in over 4 months

when the second animal was located in them. M2 and M4 more closely

overlapped in their use of two of the nests. M2 was located in the

first of these on 1 May 1984 and again on 21 June. M4 was found in this

same nest on 29 June. M2 was located in the second nest on 6 April

1984, 1 May, 29 June and 22 February 1985. M4 was found in this nest on

5 June 1984 and again on 1 September. A nest "shared" by M1 and Fl was

used by Ml on 15 April 1984 and again on 15 March 1985, then by F1 on 19

April 1985. Because this nest was in an area outside of Ml's primary

area of use in April 1985, he may have been beginning to seeking females

on the area at that time.

A close overlap in nest use occurred on 14 and 15 December 1984

between F1 and F2. At 0920 both were in nests about 100 m apart.

During the afternoon Fl was over 300 m ENE of her first location and F2







49

was near the edge of Lake Rowan, over 300 m SSW of her morning location.

At 1632 F2 was located very near her afternoon location, but Fl was

found in the nest F2 had occupied that morning. In the first two

tracking periods of the next day, Fl was still in the "shared" nest and

F2 was over 300 m away in a nest not far from her two previous

locations. Following this, neither squirrel was relocated in the

"shared" nest.

Percent of Locations in a Nest

The percent of total locations in which squirrels were in a nest

varied considerably. As seen in Table 13, 50.7% of all squirrel

locations were in a nest, but means varied from 32.8-65.1% for

individual squirrels and from 34.4-69.7% for individual tracking

sessions. Figure 15 shows individual and mean percent of locations in a

nest by tracking session as well as mean temperature of tracking days in

each session. A strong negative correlation between temperature and

percent locations is evident. The r2 (coefficient of determination)

value for this relationship is 0.84. Only between sessions 1 and 2 did

temperature and percent locations in a nest vary positively. This may

be explained by heavy rainfall (6.8 cm) on tracking days in session 1

compared with session 2 (0.18 cm), squirrels were usually located in a

nest during heavy rains. Increased pine cone-cutting in session 2 also

may have contributed to decreased nest use.

The negative relationship between temperature and nest use is

further demonstrated by the fact that only during the two "coldest"

tracking sessions (4 and 5) was the percent of locations in a nest

higher during the middle than the last tracking period of the day

(Fig. 16). During these two sessions, peak temperatures were not





















Table 13. Summary of percent of fox squirrel locations in a nest.



Individual M1 M2 M3 M4 Fl F2 ALL M F

% of all
Locations
in a Nest 45.0 49.3 32.8 53.8 65.1 60.1 50.7

% of Tracking Session (T. S.)
Locations in a Nest

T. S. #1 42.9 40.9 36.4 66.7 46.5

T. S. #2 37.5 33.3 29.2 38.9 34.4

T. S. #3 41.7 50.0 33.3 75.0 48.6

T. S. #4 56.5 75.0 73.9 73.9 69.7 65.1 73.9

T. S. #5 54.2 54.2 58.3 58.3 56.3 54.2 58.3

T. S. #6 37.5 45.8 58.3 50.0 47.9 41.7 54.2

T. S. #4-6 49.3 57.4 63.4 60.6 57.7 53.2 62.0


































S
S.
* .
* S
S
* S
S
S

S
S
S
S
S
S

0
S
S
S


*
*
*
*
*


S
S
* S
S S
5 5
5 0
S
0
S
S
S S
5
S
S
S
S
S
5
0
5
S.
55
S


I I I I I
1 2 3 4 5

JUL SEP NOV JAN



TRACKING SESSION


Figure 15.


Air temperature and percent of squirrel locations

in nests by tracking session. Solid line connects

mean tracking-day temperatures, dotted line, mean

percent of all squirrel locations in a nest.


-26










-24














m
>








m
-22. 7










C










-18











-16


3. a


I
6

MAY


MAR


'"


--


v











































1 2 3 4 5


SEP


NOV


JAN


MAR


TRACKING PERIOD AND SESSION


Mean percent of all
tracking period and
B = middle 1/3, and


squirrel
session.
C = last


locations in nests by
A = first 1/3,
1/3 of daylight period.


JUL


ABC
6
MAY


Figure 16.







53

reached until later in the day, and squirrels often stayed in the nest

through period B and became active in period C. During warmer periods,

overall percent of locations in the nest dropped and were at their

lowest during the warm, middle period of the day.

Females had a higher percent of locations in a nest than males in

Sessions 4-6. Most of the difference occurred in period B, when 58.3%

of female locations were in a nest compared to 34.8% of male locations.

Percent of locations in Periods A and C were only slightly higher

(<2.0%) for females than for males.

Nest Location and Composition

Squirrel nests were found in six tree species: turkey oak (68.6%),

longleaf pine (17.7%), live oak (4.9%), post oak (3.9%), laurel oak

(3.9%), and slash pine (Pinus elliottii) (1.0%). Percent of nest uses

was somewhat disproportionate to percent of total nests in turkey oaks

(59%), live oaks (9.3%), and post oaks (8.6%). This resulted from a few

heavily used nests in trees of the latter two species.

As previously mentioned, tree cavities were seldom used by the

tracked squirrels. Only seven cavities were used (7.4% of all nests) a

total of nine times (3.4% of all nests uses). Six of the nine cavity

uses occurred during adverse weather conditions of either cold (5.5 C)

or rain. During this study, squirrels were never observed using "stump

dens" or seeking refuge in gopher tortoise burrows, as reported by Moore

(1957).

Forty-seven nests were counted on 10 ha in ecotone and 27 on 10 ha

in upland, resulting in means of 4.7 and 2.7 nests/hectare for the two

areas, respectively. A T-test revealed this difference to be

significant at P < 0.05. Mean dbh of random and turkey oaks containing







54

nests were significantly different in both ecotone and upland

(P < 0.01), suggesting that squirrels select the larger trees (Fig. 17).

Nest composition (twigs, leaves, Spanish moss and/or longleaf pine

needles) was similar in both habitats for all materials except Spanish

moss, found in 87% of ecotone nests and only 59% of upland nests.

Presumably this difference is due to greater availability of Spanish

moss in the ecotone.










ECOTONE
NEST






.11 1


12 18
UPLAND
NEST


24 30 36 42 48


(1L


12 16 20 24 28 32


I


ECOTONE
RANDOM






II


12 18 24 30 36 42 48
UPLAND
RANDOM




j_.L


12 16 20 24 28 32


DBH (CM)


Figure 17. Frequency and distribution of turkey oaks
containing nests compared with randomly
selected turkey oaks in ecotone and upland.


A


--


Y


_


n-


-~ -


-,I
A


m















DISCUSSION


Food Resources



As shown by this and other studies (Harlow and Eikum 1963, Nixon

et al. 1980, and Christisen and Kearby 1984), mast production is highly

variable. The implication of mast patchiness for consumers is a need

for large areas encompassing diverse species of mast-producing trees.

When one crop fails (such as the turkey oak), others (e.g. live and post

oak) may be available. During the 1984 turkey oak acorn failure, Ml's

eastward home-range shift brought him into the live oak fringe around

Barco Lake. M2's home range included the fringe of Anderson Cue. All

of the tracked squirrels used a variety of habitats.

Numerous factors cause variation in mast production. They may

include climate, tree size, inherent genetic potential, site elevation,

and soil characteristics, previous production, crown size, insects, and

disease. Understanding the effects of these factors can help explain

variability as well as aid in prediction of mast production.

Seed production may be enhanced at lower elevations by greater moisture

and soil nutrient availability. At the Ordway Preserve, this effect was

more evident in turkey oaks than in longleaf pines (which have very deep

taproots). Usually, increased tree size also is associated with higher

mast production. Both tree size and elevation

56







57

affected seed production in the longleaf pines and turkey oaks on the

Ordway Preserve.

Seed production on the Ordway Preserve also was affected by insect

infestation. Larval stages of various insects were found in both pine

cones and acorns. Ebel (1963) found species of the cone moth

(Dioryctria sp.) (commonly called "coneworms") to be the most injurious

insects attacking longleaf pine seeds. No larvae of these species were

identified during this study, but several cones showed typical signs of

having been infested by them. Small orange larvae of the cone midge

(Itonididae) were found in longleaf pine cones. Occurrence of this

insect was reported by Ebel (1963) to be most often associated with

coneworm infestation. Larvae of the cone moth Laspeyresia sp. also were

found in pine cones on the Ordway Preserve. Although not identified at

the time, the larvae found in most of the turkey oak acorns on the

ground on the Ordway Preserve were likely cucurlionid weevils. In a

study in Marion County, Florida, Harlow and Eikum (1963) found

cucurlionid infestation rates of 36.9-81.2% in turkey oak acorns.

Longleaf pines are thought to produce exceptionally heavy seed

crops every 5-7 years (Schopmeyer 1974). The periodicity of turkey oak

acorn crops has not been widely studied, but if like other oaks of the

subgenus Erythrobalanus (red oaks), very heavy or very poor crops rarely

occur consecutively. Seed-bearing is accompanied by a depletion of

stored nutrients and loss of foliage, thus the seed crop of one year

affects that of the next (Matthews 1963). Turkey oaks might be expected

to yield heavy crops as often as every 4 years. Barrett (1931), Gysel

(1956), and Beck and Olson (1968) have reported complementary

seed-bearing years between the red and white oak groups. This has







58

obvious advantages for mast consumers where species of both groups are

found together. At the Ordway Preserve, white oaks (e.g. live and

laurel oaks) are found primarily in lower areas near water. Although

live oak acorn production was not measured directly, many acorns were

observed both on the ground and in the trees within the ranges of Ml and

M4.

The longleaf pine community is dependent on fire for persistence.

The original longleaf pine forests may have burned an average of every

3-5 years (Means and Grow 1985). Suppression of fire, too-frequent

fires (annual), logging, and tapping for turpentine have reduced pine

and increased oak densities over much of the fox squirrel's range.

Properly managed, controlled burning can reverse this trend. After

dropping in October-November, longleaf pine seeds require bare mineral

soil without shade for germination. Once germinated,

(November-December), the seedlings must be protected from fire for one

year (Wakely 1947). Periodic summer burns are recommended to prepare

the seedbed for longleaf pines and help to control turkey oaks.

Due to the extreme variability of seed production, mixed stands of

mast-producing trees are recommended for wildlife (Christisen 1955,

Collins 1961, Goodrum et al. 1971, Christisen and Kearby 1984). The

results of our studies on the primary foods of Sherman's fox squirrel

clearly indicate their need for heterogenous habitat. Longleaf pines

are most important, but mast-producing oaks of both the red and white

oak groups also are necessary. Access to other mast-producing trees

such as hickory also is desirable. (Discarded shells of hickory nuts

were observed several times where fox squirrels were known to have fed).

Lower slopes in ecotonal habitat and the live oak fringes of sandhill







59

lakes are very important due to their higher mast yields and species

diversity.



Home Range



The patchy distribution of the primary food resources of

southeastern fox squirrels may well explain why their home ranges are

larger than predicted on the basis of body size and diet (Weigl et al.

in press). In areas of more uniform resource distribution, western fox

squirrel home ranges average from 0.8-7.0 ha (MCP) (Baumgartner 1943,

Bernard 1972, Adams 1973, Havera and Nixon 1978). In contrast, mean

southeastern fox squirrel ranges average from 19.5-30.3 ha (MCP) in

Georgia (Hilliard 1979), North Carolina (Weigl et al. in press), and

Florida (this study).

In this study, tracking spanned an average of 7 months, and

squirrels were located on average 88 times over 48 tracking days. The

resulting MCP home ranges were 40.0 ha for males and 20.6 ha for

females. Hilliard (1979) tracked S. n. niger in Georgia an average of

1.4 months and located individuals on average 203 times over a period of

32 tracking days. Mean MCP home ranges were 26.4 ha for males and

13.0 ha for females. In North Carolina, Weigl et al. (in press) tracked

S. n. niger over an average of 2 months, locating each individual 78

times. Mean MCP range was 22.8 ha for males and 16.2 ha for females.

The different tracking schedules make it difficult to conclude that

S. n. shermani has a larger home range than S. n. niger, but this may

well be true since S. n. shermani is the largest of the southeastern fox

squirrels (Williams 1977).







60

Home range is clearly larger in males than in females, frequently

2-3 times larger in Florida. Short-term intensity of home-range use may

be similar between the two sexes, but cumulative home range use is more

even in females than in males. Female fox squirrels tend to be more

sedentary (Nixon et al. 1980), while males generally make more

long-distance forays, cover larger areas, and may have greater home

range overlap.

Although usually solitary, the squirrels were not strictly

territorial. Animals overlapped in both home range and nest use. No

evidence of home range defense was observed in these squirrels. With

their smaller home ranges, females might be more likely than males to

defend a core area, particularly when rearing a litter.

Home-range size and use may vary with seasonal food abundance,

reproductive activity, and climate. Home ranges may shift during

shortages of a particular food resource (e.g., Ml). Increased

long-distance forays are characteristic of males before and during the

breeding season. Extremes of temperature and precipitation may cause

decreased activity, thus decreasing home-range size. During this study,

a combination of these and other variables typically acted on squirrel

behavior and home range size, making their effects difficult to

separate.



Nests



Nest use provided additional insight into the ecology of Sherman's

fox squirrel. Percent of time spent in the nest increased both as

temperature decreased and during periods of heavy rain. Only during the









two "coldest" tracking sessions was percent of locations in a nest

higher during the second than the third period of the day, suggesting

that squirrels became active later in the day when temperatures were

warmer. Weigl et al. (in press) also reported later onset of activity

during winter months. Female squirrels spent more time in the nest than

males, providing further evidence of the sedentary tendencies of female

fox squirrels.

Most nests were leaf nests rather than cavities (dens). While

important in colder climates, apparently dens are not required for

survival in Florida. Hilliard (1979) reported similar results but

thought that dens were essential for litter survival and that den trees

limited fox squirrel populations. D. David (pers. comm.) installed

squirrel nest boxes in suitable habitat but reported Sherman's fox

squirrels used them very little. While juveniles may indeed be at some

greater risk of predation without them, this study provides no evidence

that lack of den trees limits squirrel populations in mild southern

climates. Much more evidence exists to indicate that food resources are

the primary limiting factor of southeastern fox squirrel populations.

Turkey oaks containing squirrel nests were larger than randomly

sampled turkey oaks. Allen (1952) and Hilliard (1979) also observed

that fox squirrels appear to select larger trees. Larger trees have

obvious advantages for nest stability and potential size. Large,

well-insulated nests provide the best protection from the elements and

were often used by squirrels during inclement weather.

More nests were found in ecotone than in upland, indicating higher

squirrel densities in ecotone. Advantages of ecotonal habitat are

several: 1) turkey oak acorn production is higher, 2) other important







62

mast producers such as live, laurel, and sand post oaks occur, 3) food

resources in general are more diverse, 4) Spanish moss, important for

winter nest insulation, is more abundant, and 5) the increased ground

and canopy cover can provide squirrels better protection from raptor

predation. Clearly, the ecotonal lower slopes of the sandhill are a

vital part of the fox squirrel's habitat.

The mean number of nests in ecotone and upland combined was

3.7/hectare. If squirrels use 30 nests/year as calculated (although

some overlap in nest use occurs, its effect may be cancelled by the
2
persistence of unused nests), 12.3 squirrels would be expected per km2

Although this number is higher than the 8.4/km2 predicted by Humphrey et

al. (1985), it is consistent both with the number of squirrels observed

by myself on the squirrel study area and with the predictions of other

investigators at the Ordway Preserve (M. Sunquist, pers. comm.).

Fewer squirrels would be expected to occur in less favorable habitat.

Nest counts appeared to provide a reliable estimate of squirrel density

on the study area and should now be tested as an index of squirrel

abundance in other parts of the animal's range. If squirrel

distribution and abundance can be determined from nest counts, informed

management of squirrel populations will be made possible.

How these densities compare to those of other subspecies is

difficult to conclude. In a study of S. n. niger in North Carolina,
2
Weigl et al. (in press) reported a mean density of 5 squirrels/km but

their work was conducted on a greater diversity of sites and may have

better represented average site quality. For S. n. niger in Georgia,

Hilliard (1979) reported a density of 26 squirrels/km2 over the short

duration of his study. High densities during Weigl's study were 28, 22,







63

and 19/km2, which are comparable to that reported by Hilliard. For

S. n. shermani in Florida, Moore (1957) calculated 38 squirrels/km2

based on two years of study near Welaka, Putnam Co., FL, an area

approximately 60 km southeast of the Ordway Preserve.

Only 10-20% of the original longleaf pine sandhill habitat remains

in Florida. Populations of Sherman's fox squirrel have declined as a

result of this habitat loss. Further habitat destruction will surely

result in continued decline, and perhaps even extiction of Sherman's fox

squirrel unless substantial refuges are established. Due to this

squirrel's large home range size and patchy food resource distribution,

refuges on the order of several square miles, not just small parcels,

will be required to sustain viable squirrel populations. Given that

typical squirrel habitat occurs on approximately 1/3 (12km2) of the

37km2 Ordway Preserve, and that squirrels may also use additional, less

favorable habitat, I estimate the population of fox squirrels on the

Ordway Preserve to be about 200 animals. The Ordway Preserve, then, is

a good example of a minimum refuge (>10mi ) necessary to sustain viable

fox squirrel populations. Preservation and maintenance of large areas

of heterogenous, natural sandhill habitat such as the Ordway Preserve

are key to the survival of Sherman's fox squirrel and perhaps numerous

other species of the sandhills as well.




















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-------- 1980. Winter feeding of fox and gray
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-------- 1954. Fox squirrel receptionists. Everglades Nat. Hist.
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------- 1956. Variation in the fox squirrel in Florida.
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BIOGRAPHICAL SKETCH


Angela Torres Kantola was born in Jones, Oklahoma, in 1961. She

graduated from Mason High School, Tulsa, in 1979, and from Oklahoma

State University, Stillwater, in 1983 with a B. S. in wildlife ecology.

She was married to Edward C. Kantola in July, 1983.

During her graduate education at the University of Florida, Angela

was employed as a biologist (wildlife) with the U. S. Fish and Wildlife

Service Sirenia Project through the Service's Cooperative Education

Program. Angela received the M. S. in forest resources and conservation

with a concentration in wildlife ecology in August 1986.










I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a thesis for the degree of Master of
Science.



Stephen R. Hump rey,/Chairman
Associate Professor, Forest
Resources and Conservation


I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a thesis for the degree of Master of
Science.



icha W. Collopy -
Associate Professor, Forest
Resources and Conservation


I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a thesis for the degree of Master of
Science.




freesor, Forest R sources
and Conservation


I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a thesis for the degree of Master of
Science.



/em n E. Sunqrifst
Associate Professor, Forest
Resources and Conservation









This thesis was submitted to the Graduate Faculty of the School of
Forest Resources and Conservation in the College of Agriculture and to
the Graduate School and was accepted as partial fulfillment of the
requirements for the degree of Master of Science.


Director, Forest Resource and
Conservation
C-.


Dean, Graduate School


August 1986




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