2009 SOUTHEASTERN NATURALIST 8(1):157–166
Habitat Use by a Dense Population of Southern Fox Squirrels
James C. Lee1, David A. Osborn1,*, and Karl V. Miller1
Abstract - We determined seasonal macro- and microhabitat preferences of radiocollared
Sciurus niger niger (Southern Fox Squirrel) in a high-density population.
Fox squirrels preferred hardwood, live oak, and mixed hardwood-pine macrohabitats
to pine, early successional, and turf macrohabitats. During winter, early summer, and
late summer, they preferred mixed hardwood-pine, live oak, and hardwood microhabitats
to pine microhabitats. Fox squirrels preferred an open or moderate crown
spacing to a dense crown spacing during all seasons, and during the summer, they
preferred microhabitats with at least 1 cone-bearing pine tree. Preferred microhabitats
had a short-open or leaf-litter understory structure. Although the hardwood and
hardwood-pine habitats on our barrier island study site differed from typical pinedominated
southeastern fox squirrel habitat, our results demonstrating preference
for these types indicated that they are capable of supporting an abundant fox squirrel
population when managed by mowing, burning, and light timber harvesting.
Introduction
Sciurus niger niger L.(Southern Fox Squirrel) is 1 of 4 southeastern fox
squirrel subspecies that have declined in abundance and distribution during
recent years, primarily because of habitat modifications (Ha 1983, Loeb and
Lennartz 1989, Loeb and Moncrief 1993, Taylor 1973, Weigl et al. 1989).
In the southeastern US, fox squirrels prefer mature Pinus palustris Mill.
(Longleaf Pine), mixed Pinus spp.- Quercus spp. (pine-oak), bottomland
hardwood, and Carolina bay (small pine-hardwood wetlands) forests with
relatively open or herbaceous understories. However, these studies focused
on low-density (<38 fox squirrels/km2) populations (Edwards et al. 1989,
Ha 1983, Hilliard 1979, Kantola and Humphrey 1990, Perkins and Conner
2004, Perkins et al. 2008, Weigl et al. 1989).
On Spring Island, SC, a dense population (>75/km2) of Southern Fox Squirrels
has increased in size during the past 10 years concurrently with habitat
modifications associated with residential development (Lee et al. 2008).
Although short-term increases in squirrel numbers are common after years of
food abundance, Southern Fox Squirrel populations rarely are sustained at the
densities observed on Spring Island (Weigl et al. 1989). Because squirrel abundance
is usually regarded as an indicator of habitat quality, characterization of
the preferred habitats on Spring Island may alter wildlife management practices
throughout the Southeast. Subspecies of southeastern fox squirrels are
ecologically similar (Weigl et al. 1989), so these recommendations probably
apply to other southeastern fox squirrel subspecies. Our objective was to examine
seasonal macro- and microhabitat use by this unusually dense Southern Fox
Squirrel population and to characterize preferred habitats.
1Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia,
Athens, GA 30602. *Corresponding author - Osborn@warnell.uga.edu.
158 Southeastern Naturalist Vol. 8, No. 1
Study Area
Spring Island is a 1200-ha sea island located between Beaufort, SC and
Savannah, GA. About 1000 ha of the island are forested, and the remainder is
fallow fields, wildlife plantings, and a golf course. During the study, there were
about 100 residential, administrative, or recreational buildings on the island.
The topography of Spring Island is mostly level, and its soils are characterized
as fine sand or fine sandy loam (USDA 1980). Spring Island, which
formed as a dune ridge during the late Pleistocene Epoch, is separated from
the mainland and other sea islands by 200–500 m of salt marsh and tidal
rivers. The climate is subtropical, with mild winters and hot, humid summers.
Yearly rainfall averages about 125 cm, with most precipitation falling
between April and October (Kovacik and Winberry 1987).
Forests on Spring Island are a heterogeneous mixture of mixed hardwoods
and pines with numerous, small (<3 ha) stands of pine, Quercus virginiana
Mill. (Live Oak), and mixed hardwoods. Most overstory trees are >40 years
old. Pinus taeda L. (Loblolly Pine), Carya spp. (hickories), Sabal palmetto
Walter (Cabbage Palm), Q. haemispherica Michx. (Laurel Oak), Live Oak,
Liquidambar styracifl ua L. (Sweetgum), Q. falcata Michx. (Southern Red
Oak), Q. nigra L. (Water Oak), and Nyssa sylvatica Marsh. (Blackgum) are
common trees. Most stands lack mid-stories, but have brushy understories
with intermittent openings where they are burned, mowed, or shaded by the
canopy. Myrica cerifera L. (Wax Myrtle), oaks, Sweetgum, Sassafras albidum
Nutt. (Sassafras), Ilex vomitoria Aiton (Yaupon), Serenoa repens Bartram
(Saw Palmetto), and Smilax spp. (greenbriars) are common understory plants.
Methods
We trapped fox squirrels in wooden Mosby-style box traps (Day et al.
1980) baited with corn, pecans, or a combination of both during August
1998–October 1998, December 1998, February 1999–March 1999, and May
1999–June 1999. Trapping effort was evenly distributed throughout the
island.
Trapped squirrels were placed into a nylon mesh bag, where they were
aged and sexed (Dimmick and Pelton 1994), and weighed to the nearest
10.0 g with a 2.0-kg spring scale (Douglas Homs Corp., Belmont, CA).
Forty-seven squirrels, each weighing >900 g were immobilized with 3–5 ml
of methoxyfl urane (administered by inhalation) or with 20–30 mg ketamine
hydrochloride (administered by intramuscular injection) and fitted with a
radio-collar (Advanced Telemetry Systems, Isanti, MN or Telemetry Solutions,
Walnut Creek, CA). Collars weighed 23–27 g, had an expected battery
life of 2 years, an effective range of 0.5–2.0 km, and a mortality switch that
activated when the collar remained motionless for 8.0 hours. Number 1 or 3
monel fingerling tags (National Band and Tag Company, Newport, KY) were
attached to both ears of each radio-collared squirrel. After recovering from
the immobilant (1 hour for methoxyfl urane, 3 hours for ketamine hydrochloride),
the squirrels were released at their capture sites.
2009 J.C. Lee, D.A. Osborn, and K.V. Miller 159
We monitored the activities of 17–31 radio-collared squirrels during each
season. Each squirrel was located at least 30 times per season at random
times between 0.5 hours after sunrise and 0.5 hours before sunset. Seasons
were based on plant phenology and were defined as: fall = 1 October 1998 to
15 January 1999, winter = 16 January 1999 to 15 March 1999, spring = 16
March 1999 to 1 June 1999, early summer = June 1999 and July 1999, and
late summer = August 1999 and September 1999 (Weigl et al. 1989).
Locations of radio-collared squirrels were determined by using the homing
method (Mech 1983). A squirrel’s location was recorded with a global
positioning system (GPS) receiver (Geoexplorer II, Trimble, Sacramento,
CA). Later, the positions (≥25 per squirrel location) were differentially corrected
and averaged using the computer program PATHFINDER (Trimble,
Sacramento, CA).
Because species composition of a forest stand is not the only determinant
of fox squirrel habitat suitability, we examined additional aspects of habitat
use. We considered forest stands (a contiguous group of trees sufficiently
uniform in species composition, arrangement of age classes, and condition to
be a distinguishable unit; Smith 1962), fields, and the golf course to be macrohabitats,
whereas unique habitat features within 30 m (0.3 ha) of a squirrel’s
location were microhabitats. When a squirrel was located, macrohabitats classified as pine (>80% of overstory species composition was pine), hardwood
(>80% was hardwoods), live oak (>80% was live oak), mixed (<80% pine and
<80% hardwood), turf (golf course and shortgrass fields), and early successional
(fallow fields and wildlife plantings) were recorded. To compare the
use of macrohabitats relative to their availability on Spring Island, we used a
geographical information system (GIS) macrohabitat coverage based on aerial
photographs that were taken in 1994 (BDA Consulting, Orlando, FL). The
coverage was ground-truthed and updated in 1999. We imported the locations
of radio-collared squirrels into ARCVIEW (Environmental Systems Research
Institute, Redlands, CA) and overlaid them onto this coverage. Seasonal home
ranges (95% kernel; Worton 1989) were generated for each squirrel with the
Animal Movement extension to Arcview (Hooge and Eichenlaub 1997). We
intersected squirrel locations and home ranges to determine proportional use
of macrohabitats by fox squirrels during each season. Microhabitat variables
(Table 1) associated with squirrel locations also were recorded. To compare
the use of microhabitats relative to their availability on Spring Island, we measured
these variables within 100 randomly chosen 0.3-ha plots. The plots were
randomly generated with the Animal Movement extension to Arcview and we
subsequently navigated to each plot using a GPS receiver.
Compositional analysis (Aebischer et al. 1993) was used for all habitat
analyses. Multivariate analysis of variance with Wilk’s Lambda (multivariate
F approximation), constructed using randomization (Edgington 1980),
was used to detect deviations (P ≤ 0.05) from random habitat use. Macroand
microhabitat variables were ranked according to their use, and paired
t-tests were used to detect differences between habitat variables (MacComp
160 Southeastern Naturalist Vol. 8, No. 1
0.90; J. Carroll, Warnell School of Forestry and Natural Resources, University
of Georgia, Athens, GA, pers. comm.).
Macrohabitat analyses included 2 spatial scales: habitat proportions
within the home range versus habitat proportions within the study area,
and habitat proportions of individual radio-locations versus habitat proportions
within the home range. These scales are equivalent to second-order
and third-order selection processes, respectively (Johnson 1980). This
experimental design provides for the recognition of habitat types that are
important, but not often used.
Microhabitat variables available on the study area were compared to
individual squirrels’ radio-locations. We used sub-compositional analysis
(N. Aebischer, The Game Conservancy, Fordingbridge, Hampshire, UK,
pers. comm.) to determine crown-spacing class preferences within overstory
composition classes. For example, crown-spacing classes within the pine
overstory composition class were analyzed separately from crown-spacing
classes within the live oak overstory composition class because average tree
crown diameter varied greatly, especially between live oaks and pines.
Results
We captured 154 fox squirrels during August 1998–June 1999. Trapping
success ranged from 1 capture/160 trap days during August 1998–October
1998 to 1 capture/4 trap-days during February 1999–March 1999. Thirtynine
fox squirrels were located frequently enough (≥30 times) during at
least one season to include in the analyses, and 17–29 radio-collared squirrels
were used for analyses during each season. We recorded 3049 radiolocations
between October 1998 and September 1999.
Table 1. Variables used to characterize microhabitats (0.3-ha plots) on Spring Island, SC,
1998–1999.
Variable Description
Overstory composition Overstory species composition classified as hardwood (>80%
hardwood tree species), pine (>80% pine tree species), mixed
(<80% pine and <80% hardwood tree species), and live oak
(>80% live oaks).
Crown spacing Overstory crown spacing classified as open (tree crowns >3 m
apart), moderate (tree crowns <3 m apart but not overlapping)
and dense (tree crowns overlapping). Crown spacing classes
correlated to our perception of how easily a squirrel could
travel through the canopy (e.g., open was difficult or impossible
to travel through, moderate offered some difficulty but still allowed
travel, and dense offered unrestricted travel through the
canopy).
Understory structure Understory structure classified as short-open (ground cover <1 m
tall and <50% dense, grass, or bare ground), tall-open (ground
cover >1 m tall and <50% dense), short-dense (ground cover
<1 m tall >50% dense), tall-dense (ground cover >1 m tall and
>50% dense), and leaf litter.
Cone-bearing pine Presence or absence of a cone-bearing pine.
2009 J.C. Lee, D.A. Osborn, and K.V. Miller 161
Macrohabitat use was non-random during all seasons (Table 2). Mixed,
hardwood, and live oak macrohabitats were generally preferred over turf,
early successional, and pine. During early and late summer, turf ranked higher
than if it was selected randomly. Pine macrohabitats generally were avoided,
although loblolly pines were easily accessible to squirrels as components of
mixed stands or scattered through predominately hardwood stands. We did not
notice any strong seasonal differences in macrohabitat selection.
Microhabitat use, as measured by the overstory composition variable was
non-random during winter, early summer, and late summer (Table 3). Hardwood
and mixed microhabitats were preferred during winter and mixed and
live oak microhabitats were preferred during early and late summer. The pine
microhabitat was not preferred during any season. For hardwood, live oak,
and mixed microhabitats during all seasons, and pine microhabitats during
spring, open and moderate crown-spacing classes were preferred (P < 0.05)
to the dense crown-spacing class, but differences between open and moderate
crown-spacing classes were rarely significant (P > 0.05). Short-open
and leaf-litter understories were generally preferred to tall-open, tall-dense,
and short-dense understories, but they were rarely significantly different
from each other (Table 3). Microhabitats containing a cone-bearing pine
were either not preferred or avoided during fall, winter and spring. However,
they were preferred during early and late summer (P = 0.001).
The mean number of tree species in 100 random 0.3-ha sample plots was
4.34. Thirty-five percent of the sample plots had leaf-litter or short-open
understory classes, whereas the remaining plots’ understory structure classes
were tall-open, short-dense, or tall-dense. At least one cone-bearing pine was
present on 82% of the sample plots.
Discussion
The typically sparse populations of southeastern fox squirrels have been
associated with large, continuous, low-diversity forests of fire-maintained
Table 2. Seasonal preference rankings of macrohabitats used by fox squirrels on Spring Island,
SC, October 1998–September 1999.
Comparison Ranking1,2,3 P-value
Study area vs. home range
Fall HA > M > LOBC > T > ESC > PAB 0.05
Winter MA > HE > LOABCD > TC > ESD > PBE <0.01
Spring M > H > LOAB > T > ES > PAB <0.01
Early summer MA > H > TA > ESD > LOABCD > PB <0.01
Late summer MAE > LOABCD > TC > HE > PB > ESD <0.01
Home range vs. radio-locations4
Fall LOAB > HCD > PD > T > MAC > ESB 0.03
Winter LOA > M > HB > ESA > T > PB <0.01
Spring M > LOA > T > H > P > ESA <0.01
1> denotes preference.
2Macrohabitats with the same superscripted letter are significantly different (P < 0.05).
3H = hardwood, M = mixed, LO = live oak, T = turf, ES = early successional, P = pine.
4 Seasons without differences in preference (P > 0.05) are excluded from this table.
162 Southeastern Naturalist Vol. 8, No. 1
Longleaf Pine with a scattered hardwood component and a uniformly open or
herbaceous understory (Bangs 1899, Moore 1957, Perkins and Conner 2004,
Weigl et al. 1989). Because large-scale conversion of this forest type presumably
has led to the decline of fox squirrel distribution and abundance (Weigl et
al. 1989), many researchers have suggested that large tracts of fire-maintained
Longleaf Pine with a uniformly open understory is the optimal habitat for fox
squirrels. However, fox squirrels on Spring Island, and in other areas of the
Southeast (Edwards et al. 1989, Hilliard 1979, Kantola and Humphrey 1990),
appear to prefer areas with a higher diversity of tree species than primitive
Longleaf Pine forests contained. Furthermore, on Spring Island, the forest
understory is not uniformly open. The structure of habitat on Spring Island is
similar to that reported for populations of S. n. rufiventer Geoffrey St. Hilaire
(Midwestern Fox Squirrel) of similar densities in the northern and midwestern
United States (Allen 1942, Baumgartner 1943, Nixon and Hanson 1987).
The high-density population (75/km2) and smaller than normal home
ranges (mean annual areas of 3.4 ha for females and 9.6 ha for males) of fox
squirrels on Spring Island refl ect high habitat quality (Dasmann 1964, Lee
et al. 2008). Habitat characteristics on Spring Island are partially the result
of a history of mowing and burning. These activities maintained an open understory
to facilitate the management and hunting of Colinus virginianus L.
(Northern Bobwhite). Between the 1960s and 1990, annual burning was conducted
over most of the island. Fires caused many of the hardwood trees to
develop butt scars and then, cavities (Carey 1983), which may be important
as fox squirrel denning and litter-rearing sites (Weigl et al. 1989). Prescribed
fires caused some tree mortality that thinned the overstory and may have
contributed to the lack of a midstory over much of the island. Since 1990,
less burning was conducted, but mowing increased, which resulted in a mosaic
of understory structure classes. The fox squirrel population on Spring
Table 3. Seasonal preference rankings for overstory species composition (OSC) and understory
structure (US) microhabitat variables by fox squirrels on Spring Island, SC, October 1998–September
1999.
Microhabitat variable Season1 Ranking2,3,4 P-value
Overstory composition
Winter HA > MB > P > LOAB 0.05
Early summer MBC > LOACD > HAB > PD <0.01
Late summer MB > LOABC > HAB > PC <0.01
Understory structure
Fall SOAB > LL > SD > TDA >TOB <0.01
Winter LLABC > SODEF > TOCF > TDBE > SDAD <0.01
Spring LLABC > SODEF > SDAD > TOCF > TDBE <0.01
Early summer LLAB > SOCD > SDA > TOBD > TDC <0.01
Late summer SOE > LLAB > TOCDF > SDACD > TDBEF <0.01
1Seasons without differences in preference (P > 0.05) are excluded from this table.
2OSCs or USs with the same superscripted letter are significantly different (P < 0.05).
3H = hardwood, M = mixed, P = pine, LO = live oak, SO = short-open, LL = leaf litter, SD =
short-dense, TD = tall-dense, TO = tall-open.
4> denotes preference.
2009 J.C. Lee, D.A. Osborn, and K.V. Miller 163
Island has certainly not declined, and may have increased substantially since
then (Lee et al. 2008). Therefore, maintaining about 35% of the understory
in leaf-litter or short-open understory structure classes seems to be at least
partially responsible for the abundance of fox squirrels.
Ecotone areas are important to fox squirrels (Edwards et al. 1989, Kantola
and Humphrey 1990, Weigl et al. 1989). Because of the high degree of
interspersion on Spring Island, ecotones are nearly always ≤200 m apart.
Furthermore, macrohabitats tend to blend over large areas so that ecotones
are indistinct. The result of this interspersion is an environment in which fox
squirrels have an abundance of resources nearby during all seasons.
Certain habitat features such as wildlife plantings, cone-bearing pines,
and the golf course appeared seasonally important to fox squirrels (Lee et al.
2001). Many of the early successional fields on Spring Island were planted
in wheat, which was available as food to fox squirrels during May and June
1999. Although fox squirrels often were seen feeding in these wildlife plantings,
no radio-collared fox squirrels were observed to travel outside their
normal ranges to take advantage of these wheat plantings, and the early
successional macrohabitat was not preferred during any season. However,
wheat may be an important food source for fox squirrels during the spring
after a fall mast failure (Lee et al. 2001). Cone-bearing pines were an important
microhabitat feature during early and late summer, when pine seeds
were an important fox squirrel food source (Lee et al. 2001, Schultz 1997,
Weigl et al. 1989).
Because of the number of fox squirrel sightings, the golf course initially
appeared to be important to fox squirrels. Sciurus niger avicennia Howell
(Big Cypress Fox Squirrel) in Florida are more abundant near golf courses
than in natural habitats (Jodice and Humphrey 1992). However, the turf macrohabitat
ranked high only during early and late summer, when mushrooms
may have attracted fox squirrels. It is likely that our initial perception associated
with the golf course was related to the greater visibility of fox squirrels
there. Fox squirrels can be observed from afar while they are foraging on or
around the golf course and they probably habituate to humans (Jodice and
Humphrey 1992).
Loeb and Lennartz (1989) described habitats occupied by fox squirrels
as forests with large pines, sparse ground cover, and an association of
mature, mast-producing oaks. The oaks could occur as a midstory component
or as patches within pine stands. Because of the typically large home
ranges of southeastern fox squirrels (9–19 ha for females and 20–32 ha
for males; Edwards 1986, Hilliard 1979, Kantola and Humphrey 1990,
Weigl et al. 1989), researchers conclude that fox squirrels need large tracts
of land to satisfy their habitat needs. However, because fox squirrels on
Spring Island have much smaller home ranges than previously reported for
southeastern fox squirrels (Lee et al. 2008), we suspect that large homerange
sizes are not an inherent characteristic. Rather, they reflect a need by
fox squirrels in inadequate habitats to traverse a large area to satisfy their
164 Southeastern Naturalist Vol. 8, No. 1
resource requirements. Resource needs may be met in a smaller area if a
high interspersion of habitat types is present.
The most important tree species are mast-producing hardwoods, especially
oaks. A mixture of red oaks and white oaks, as on Spring Island, helps
prevent the loss of the entire mast crop if either group of species fails to produce
acorns. Because Spring Island fox squirrels were located within 30 m of
a cone-bearing pine more often than expected during early and late summer,
cone-bearing pines should be present at a minimum density of 1.0/0.3 ha.
In areas where hardwoods are a component of pine stands, they should be
dominant or co-dominant, but not part of the midstory. The canopies of the
trees should not overlap, although they need not be greater than 3 m apart. A
sparse understory is important, but it probably does not need to cover more
than 35% of the area. In the event of a fall mast failure, spring food sources
should be available (i.e., wildlife plantings, and trees such as Acer rubrum L.
[Red Maple], and Morus rubra L. [Red Mulberry]. These habitat conditions
have been encouraged on Spring Island through land management practices
such as mowing, burning, and light timber harvesting. In areas where the
conservation of Southern Fox Squirrels is a priority, quality habitat may be
created or maintained through these methods.
Acknowledgments
The Daniel B. Warnell School of Forestry and Natural Resources, the Turner
Foundation, Inc., The Spring Island Trust, and McIntire-Stennis Project Number
GEO-0093-MS provided funding for this study. John P. Carroll provided assistance
with statistical analyses. Helen J. H. Whiffen, Brian R. Chapman, and Robert J. Warren
provided helpful comments on this manuscript.
Literature Cited
Aebischer, N.J., P.A. Robertson, and R.E. Kenward. 1993. Compositional analysis of
habitat use from animal radio-tracking data. Ecology 74:1313–1325.
Allen, D.L. 1942. Populations and habits of the fox squirrel in Allegan County,
Michigan. American Midland Naturalist 27:338–379.
Bangs, O. 1899. The land mammals of peninsular Florida and the coast region of
Georgia. Proceedings of the Boston Society of Natural History 28:157–236.
Baumgartner, L.L. 1943. Fox squirrels in Ohio. Journal of Wildlife Management 7:
193–202.
Carey, A.B. 1983. Cavities in trees in hardwood forests. Pp. 167–184, In B. Melder
(Ed.). Proceedings of a Symposium on Snag Habitat Management. US Department
of Agriculture, General Technical Report SE-99. Fort Collins, CO.
Dasmann, R.F. 1964. Wildlife Biology. John Wiley and Sons, New York, NY. 231 pp.
Day, G.I., S.D. Schemnitz, and R.D. Taber. 1980. Capturing and marking wild
animals. Pp. 61–88, In S.D. Shemnitz (Ed.). Wildlife Management Techniques
Manual. Fourth Edition. The Wildlife Society, Washington, DC. 686 pp.
Dimmick, R.W., and Pelton, M.R. 1994. Criteria of Sex and Age. Pp. 169–214, In
T.A. Bookhout (Ed.). Research and Management Techniques for Wildlife and
Habitats. Fifth Edition. The Wildlife Society, Bethesda, MD. 740 pp.
Edgington, E.S. 1980. Randomization Tests. Marcell Dekker, New York, NY. 287 pp.
2009 J.C. Lee, D.A. Osborn, and K.V. Miller 165
Edwards, J.W. 1986. Habitat utilization by Southern Fox Squirrels in coastal South
Carolina. M.Sc. Thesis. Clemson University, Clemson, SC. 52 pp.
Edwards, J.W., D.C. Guynn, Jr., and M.R. Lennartz. 1989. Habitat use by Southern
Fox Squirrel in coastal South Carolina. Proceedings of the Annual Conference of
the Southeastern Association of Fish and Wildlife Agencies 43:337–345.
Ha, J.C. 1983. Food supply and home range in the Fox Squirrel (Sciurus niger). M.A.
Thesis. Wake Forest University, Winston-Salem, NC. 32 pp.
Hilliard, T.H. 1979. Radio-telemetry of fox squirrels in the Georgia Coastal Plain.
M.Sc. Thesis. University of Georgia, Athens, GA. 121 pp.
Hooge, P.N., and B. Eichenlaub. 1997. Animal movement extension to Arcview. version
1. Alaska Biological Science Center, US Geological Survey, Anchorage, AK.
Jodice, G.R., and S.R. Humphrey. 1992. Activity and diet of an urban population of
Big Cypress Fox Squirrels. Journal of Wildlife Management 56:685–692.
Johnson, D.H. 1980. The comparison of usage and availability measurements for
evaluating resource preference. Ecology 61:65–71.
Kantola, A.T., and S.R. Humphrey. 1990. Habitat use by Sherman’s Fox Squirrel
(Sciurus niger shermani) in Florida. Journal of Mammalogy 71:411–419.
Kovacik, C.F., and J.J. Winberry. 1987. South Carolina: A Geography. Westview,
Boulder, CO. 235 pp.
Lee, J.C., D.A. Osborn, and K.V. Miller. 2001. Foods eaten by a high-density population
of Southern Fox Squirrels. Florida Field Naturalist 29:29–31.
Lee, J.C., D.A. Osborn, and K.V. Miller. 2008. Characteristics of a high-density population
of Southern Fox Squirrels. American Midland Naturalist 159:385–393.
Loeb, S.C., and M.R. Lennartz. 1989. The fox squirrel (Sciurus niger) in southeastern
pine-hardwood forests. Pp. 142–147, In T.A. Waldrop (Ed.). Proceedings of
Pine-Hardwood Mixtures: A Symposium on Management and Ecology of the
Type. US Department of Agriculture, Asheville, NC. General Technical Report
SE-58.
Loeb, S.C., and N.D. Moncrief. 1993. The biology of fox squirrels (Sciurus niger)
in the Southeast: A review. Pp. 2–17, In N.D. Moncrief, J.W. Edwards, and
P.A. Tappe (Eds.). Proceedings of the Second Symposium on Southeastern Fox
Squirrels, Sciurus niger, Virginia Museum of Natural History, Martinsville, VA.
Special Publication Number 1.
Mech, L.D. 1983. Handbook of Animal Radio-Tracking. University of Minnesota,
Minneapolis, MN. 107 pp.
Moore, J.C. 1957. The natural history of the fox squirrel (Sciurus niger shermanni).
Bulletin of the American Museum of Natural History 113:7–71.
Nixon, H.R. and L.P. Hansen. 1987. Managing forests to maintain populations of
gray and fox squirrels. Illinois Department of Conservation, Springfield, IL.
Technical Bulletin 5. 35 pp.
Perkins, M.W., and L.M. Conner. 2004. Habitat use of fox squirrels in southwestern
Georgia. Journal of Wildlife Management 68:509–513.
Perkins, M.W., L.M. Conner, and M.B. Howze. 2008. the importance of hardwood
trees in the Longleaf Pine forest ecosystem for Sherman's Fox Squirrels. Forest
Ecology and Management 255:1618–1625.
Schultz, R.P. 1997. The ecology and culture of Loblolly Pine (Pinus taeda L.).
US Department of Agriculture, Agricultural Handbook 713. Washington, DC.
493 pp.
166 Southeastern Naturalist Vol. 8, No. 1
Smith, D.M. 1962. The Practice of Silviculture. 7th Edition. John Wiley and Sons,
New York, NY. 578 pp.
Taylor, G.J. 1973. Present status and habit survey of the Delmarva Fox Squirrel (S. n.
cinereus) with a discussion of reasons for its decline. Proceedings of the Annual
Conference of the Southeastern Association of Game and Fish Commissioners
27:278–287.
United States Department of Agriculture (USDA). 1980. Soil survey of Beaufort and
Jasper counties, South Carolina. Soil Conservation Service, Washington, DC.
179 pp.
Weigl, P.D., M.A. Steele, L.J. Sherman, J.C. Ha, and T.S. Sharpe. 1989. The ecology
of the Fox Squirrel (Sciurus niger) in North Carolina: Implications for survival in
the Southeast. Tall Timbers Research Station Bulletin Number 24:1–93.
Worton, B.J. 1989. Kernel methods for estimating the utilization distribution in home
range studies. Ecology 70:164–168.