2011 SOUTHEASTERN NATURALIST 10(3):509–514
Artificial Nest Cavities Designed for Use by
Small Mammals
Lara L. Catall1, Darcie L. Odom1, Jacqueline T. Bangma1, Terry L. Barrett1,
and Gary W. Barrett1,*
Abstract - Forty artificial nest cavities, composed of 7.6-cm plastic tubing (20 PVC white
and 20 ABS black), were established in a riparian hardwood forest habitat located in the
Georgia Piedmont. Nest cavities situated on wooden L-shaped platforms were secured on
Quercus nigra (Water Oak) and Q. alba (White Oak) tree trunks 1.5 m from the ground.
Peromyscus leucopus (White-footed Mouse) and Ochrotomys nuttalli (Golden Mouse)
used these artificial nest cavities during autumn, winter, and spring. White-footed Mice
(36 M, 38 F, 7 J) used the black tubes to a significantly greater extent than the white tubes
(12 M, 10 F, 0 J) (χ2 = 33.8, df = 1, P ≤ 0.01). In contrast, Golden Mice inhabited the black
tubes (3 M, 5 F, 6 J) to the same extent as the white tubes (6 M, 7 F, 0 J) (χ2 = 0.04, df =
1, P > 0.25). Black tube cavities were warmer (2.5 ºC) than white tubes during the winter
breeding season, which may partially explain why White-footed Mice, a less social species
than Golden Mice, used these artificial nests to a greater extent during winter.
Introduction
Avian species are attracted to and protected by property owners who provide
resources, such as nest boxes, feeders, and water baths, for conservation and
recreational purposes. Small mammals, perhaps inhabiting these same forests
or managed habitats, are seldom identified or appreciated, perhaps because of
factors such as their nocturnal behavior (Wolff and Hurlbutt 1982), or limited
food sources (Scarlett 2004) and nest cavities (Wolf and Batzli 2002) provided
by property owners. Occupied artificial nest cavities located in proximity to the
property owner likely would encourage familiarity with the ecological value attributed
to these small-mammal species. Therefore, our purpose was to design an
artificial nest cavity appealing to small mammals that could be located within a
managed domain.
Nest cavities provide sites for reproduction, protection from predators, and a
cache site for food (Goundie and Vessey 1986, Rose and Walke 1988). As a possible
limiting factor, nest-cavity availability may influence small-mammal population
abundance within a forest ecosystem (Brady et al. 2000, Goundie and Vessey 1986,
Vessey 1987). Luring small mammals with resources necessary for survival, such
as food and shelter, is an appropriate strategy to attract and study small-mammal
species (Rodas et al. 2009). The Ochrotomys nuttalli Harlan (Golden Mouse) and
Peromyscus leucopus Rafinesque (White-footed Mouse) compete for resources,
such as nest cavities, in a three-dimensional forest habitat space that likely impacts
population dynamics (Christopher and Barrett 2006).
1 Eugene P. Odum School of Ecology, University of Georgia, 140 East Green Street, Athens,
GA 30602. *Corresponding author - gbarrett@uga.edu.
510 Southeastern Naturalist Vol. 10, No. 3
Many studies have focused on the use of nest boxes to record and observe
mammalian behavior (Brady et al. 2000, Edwards and Guynn 1995, Wolff and
Durr 1986). Mammals have been reported to use nest boxes more frequently than
natural cavities (McComb and Noble 1981) during winter months (Nicholson
1941). Because small mammals often reside in nest boxes for long periods of
time, the nest box could provide an effective implement for investigating smallmammal
behavior and abundance (Lewellen and Vessey 1999).
In our study, artificial tube nests composed of plastic, unlike the commonly
constructed wooden-house nest box, were designed to simulate natural shelters,
such as tree cavities. We question if these artificial nest cavities would lure small
mammals, such as the White-footed Mouse and the Golden Mouse, throughout
all seasons of the year. Specifically, the objectives of our study were to determine
if small mammals would: (1) use this newly designed artificial nest cavity;
(2) prefer white or black plastic tube nest cavities; and (3) occupy nest cavities
with similar frequency during each season of the year.
Study Area
This study was conducted at Horseshoe Bend (HSB) Ecology Experimental
Site located in Athens-Clarke County, Athens, GA (33º57'N, 83º23'W). HSB
is a 14.2-ha riverine peninsula research site created by a meander of the North
Oconee River. This site is composed of highland and lowland deciduous forest,
dominated by Quercus nigra L. (Water Oak), Ligustrum sinense Loureiro (Chinese
Privet), Smilax rotundifolia L. (Greenbrier), Lonicera maackii (Ruprecht)
Herder (Amur Honeysuckle), and L. japonica Thunberg (Japanese Honeysuckle).
Quercus alba L. (White Oak) and Fagus grandifolia Ehrhart (American Beech)
are more abundant in highland habitat, whereas Betula nigra L. (River Birch) and
Liquidambar styraciflua L. (Sweetgum) are populous in lowland habitat (Christopher
and Barrett 2006, Klee et al. 2004).
Methods
Twenty white PVC (polyvinyl chloride) and twenty black ABS (acrylonitrile
butadiene styrene) tubes, 7.6 cm in diameter and 30.5 cm in length, were capped
on both ends. Holes (2.5 cm in diameter) were drilled into the caps on each end
to provide entrance/escape portals. Nonabsorbent cotton was positioned in half
the length of each tube to provide bedding material.
An experimental grid (approximately 1 ha) was established in each of the
highland and lowland habitats. Ten Water Oaks were selected in the lowland grid,
and ten White Oaks were selected in the highland grid. Each oak tree (highland
mean DBH = 81.4 ± 10.4 [SD] cm and lowland mean DBH = 43.63 ± 8.14 [SD]
cm) represented a sample station. Each station was comprised of two platforms
mounted 180º from each other 1.5 m aboveground level. Adjacent stations were
spaced on average 8.04 ± 2.02 (SD) m apart.
On each tree, one 7.6-cm-diameter white tube and one 7.6-cm-diameter black
tube was mounted on wooden platforms using bungee cords (Fig. 1). Directions
2011 L.L. Catall, D.L. Odom, J.T. Bangma, T.L. Barrett, and G.W. Barrett 511
of the platforms (360º) were randomized. Nest tubes were checked weekly
from 16 February 2009 to 17 March 2010. When checking nest tubes for smallmammal
occupancy, a #5 rubber stopper was fitted into each of the two-entrance/
escape portals. Each nest tube was then placed into a 32 gal (121.6 l) Rubbermaid
roughneck container to remove cotton and handle captive individual(s).
Location, species, ear tag number, sex, reproductive condition (females open or
Figure 1. Image of a station encompassing one black and one white tube positioned on
platforms attached to a tree 1.5 m aboveground, Horseshoe Bend Ecology Experimental
Site. Photograph © Terry L. Barrett.
512 Southeastern Naturalist Vol. 10, No. 3
closed vaginal orifice; males abdominal or scrotal testes), and weight of each
captured individual were recorded. Captured individuals were released at the site
of capture. From 14 November 2009 to 26 February 2010, dual probed maximum/
minimum thermometers (Digital Dual Sensor Thermometers SN 89212, Forestry
Supplies, Inc.) were inserted into each white and black nest tube cavity to measure
daily ambient temperatures inside each nest tube. Two random stations, one
in the highland and one in the lowland grid, were used to determine mean weekly
temperature differences between the black and white tubes. Thermometers were
rotated to new stations on a weekly basis. Mean weekly ambient temperatures
were also recorded.
A chi-square test was performed to determine treatment differences in nest
tube selection (black versus white) by White-footed Mice and Golden Mice. We
hypothesized that small mammals would select black versus white tubes in equal
proportions (50/50). Significant differences were determined at the P ≤ 0.05 level
of probability.
Results and Discussion
Only White-footed Mice and Golden Mice used the nest tubes during this
investigation, likely because of the diameter (2.5 cm) of entrance/escape portals.
White-footed Mice (n = 103) and Golden Mice (n = 27) used these artificial nest
cavities during all seasons except summer; peak use occurred during winter
months. Use of nest tubes by adult White-footed Mice during winter months of
December through February included 15 females and 13 males in black nest tubes
and 1 female and 6 males in white nest tubes. Use by adult Golden Mice during
these same months, were 3 females and 1 male in black nest tubes and 7 females
and 6 males in white nest tubes. These data confirm that White-footed Mice
dominate use of black nest tubes during the winter breeding season. Birthing
(n = 13) occurred only in black nest tubes for both small-mammal species. Birth
of young began on 17 December for White-footed Mice and not until 27 January
for Golden Mice. There was a significantly greater use of black nest tubes by
White-footed Mice, compared to white nest tubes, throughout this investigation
(χ2 = 33.8, df = 1, P ≤ 0.01). There was no significant difference between black
compared to white nest-tube use by Golden Mice (χ2 = 0.04, df = 1, P > 0.25).
We are not certain why White-footed Mice and Golden Mice did not use the
nest tubes during summer. However, Wolff and Hurlbutt (1982) and Wolff and
Durr (1986) found that White-footed Mice nested underground or in hollow trees
during summer. Madison et al. (1984) reported that White-footed Mice nested
singly in trees during summer.
Southern populations of Golden Mice breed mostly during winter, and avoid
breeding during summer (Linzey and Packard 1977, McCarley 1958, Pearson
1953, Rose 2008), suggesting less need for use of nest tubes during summer. We
observed the same breeding pattern at HSB, which may partially explain why
Golden Mice did not use nest tubes during summer.
Because black tubes were preferred over white tubes, we explored mean
weekly maximum and minimum temperature within each colored tube during
2011 L.L. Catall, D.L. Odom, J.T. Bangma, T.L. Barrett, and G.W. Barrett 513
winter months in both the highland and the lowland forest habitat (i.e., from
mid-November 2009 through late February 2010). Mean weekly ambient temperatures
were also recorded during this same time period (Fig. 2). Black tubes
reached a higher daily maximum temperature than did the white tubes. Mean recorded
maximum temperatures in the black tubes were 2.5 ºC greater than in the
white tubes throughout the winter months. Black and white tubes reached similar
minimum temperatures at night throughout the course of the study (Fig. 2).
Our study proposed to create an economical artificial nest cavity that property
owners can use to attract small mammals. As noted, the black nest tube cavities
were used more frequently than the white ones. An estimated cost to construct
a single black ABS nest tube is approximately fifteen U.S. dollars ($15.00)
excluding labor (i.e., similar to or less expensive than numerous avian nest-box
designs). We suggest that these small-mammal artificial nest cavities would benefi
t property owners and native small-mammal fauna.
Acknowledgments
Thanks are extended to James O. Moree, Nathan L. Pratt, and Alex D. Wright for field
assistance. This study was supported in part by funds from the Eugene P. Odum Endowed
Chair in Ecology held by G.W. Barrett.
Figure 2. Mean weekly temperatures (ºC) recorded for highland and lowland black and
white nest tubes, including mean weekly ambient temperature, from 14 November 2009
to 26 February 2010.
514 Southeastern Naturalist Vol. 10, No. 3
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