Site by Bennett Web & Design Co.
2007 SOUTHEASTERN NATURALIST 6(3):407–412
Double Captures of Peromyscus leucopus (White-footed
Mouse and Ochrotomys nuttalli (Golden Mouse)
Cory C. Christopher1 and Gary W. Barrett2,*
Abstract - We report the first interspecific double captures (n = 14) of Peromyscus
leucopus (white-footed mouse) and Ochrotomys nuttalli (golden mouse). Intraspecific
double captures of white-footed mice (57.0% of all double captures) were
heterosexual (likely mating pairs). Overall, 62.0% of the double captures for both
species were heterosexual, suggesting that there appears to exist a strong conspecific,
heterosexual odor preference. The large number of intra- and interspecific double
captures (n = 103) also suggests minimal interference or exploitation competition
between these two small mammal species of similar body mass and life histories.
Peromyscus nuttalli Rafinesque (white-footed mouse) and Ochrotomys
nuttalli Harlan (golden mouse) have similar body masses, nest-site references,
home-range sizes, food preferences, and periods of activity, and both
are semiarboreal and coexist in southeastern forests (Christopher and Barrett
2006, Knuth and Barrett 1984, Lackey et al. 1985, Linzey 1968, Linzey and
Packard 1977, Pruett et al. 2002). However, there have been no reports of
both species being simultaneously captured (i.e., interspecific captures) in
the same live trap.
The occurrence of two or more small mammals trapped simultaneously
(double captures) in field studies has been described by numerous
investigators (Bergstrom and Sauer 1986, Dunaway 1968, Getz 1972,
Jenkins and Llewellyn 1981, Novak 1983, Petersen 1975, Sheppe 1967,
Spencer et al. 1982). Most of these double captures were intraspecific.
The highest percentage of intraspecific double captures was heterosexual
(Getz 1972, Petersen 1975, Slade 1976; but see Feldhamer 1977). Heterosexual
double captures were especially prevalent during the breeding
season (Novak 1983).
Blaustein and Rothstein (1978), Feldhamer (1977), Getz (1972), Jenkins
and Llewellyn (1981), Novak (1983), Petersen (1975), and Spencer et al.
(1982) discuss how social structure and foraging behavior partially explains
intraspecific multiple captures. Getz (1972), for example, suggests that
multiple captures indicate sociality between individuals based on sex or age
relationships. Double captures also may be the result of trap sensitivities and
random encounters of small mammals when entering a single trap
(Bergstrom and Sauer 1986).
1Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221.
2Institute of Ecology, University of Georgia, Athens, GA 30602. *Corresponding
author - email@example.com.
408 Southeastern Naturalist Vol. 6, No. 3
Interspecific double captures of small mammals in single-catch livetraps
are rare. However, Petersen (1975) reported interspecific double
captures of Baiomys taylori Thomas (northern pygmy mouse) and
Reithrodontomys megalotis Baird (western harvest mouse), northern
pygmy mouse and R. fulvescens Allen (fulvous harvest mouse), and western
and fulvous harvest mice. Feldhamer (1977) reported double captures
of Peromyscus maniculatus Wagner (deer mouse), and Perognathus
parvus Peale (Great Basin pocket mouse). Evans and Holdenreid (1943)
reported similar findings regarding double captures between species of
these genera in California. We report here for the first time interspecific
double captures of white-footed and golden mice.
Past investigations suggest that the low frequency of interspecific double
captures of small mammals most often is attributed to antagonistic behavior,
social behavior during the breeding season, and population density
(Blaustein and Rothstein 1978, Jenkins and Llewellyn 1981, Novak 1983,
Petersen 1975). We questioned whether interspecific double captures in our
study could be related to a reduction in or lack of competition for resources
(nesting sites, food, or space) within the forest habitat.
This investigation was conducted at the Horse Shoe Bend (HSB) Ecological
Research Site located in Clarke County near Athens, GA (33º57'N, 83º23'W).
HSB is a 14.2-ha (35-acre) riverine peninsula formed by a meander of the North
Oconee River and is composed of bottomland and upland forest habitat (see
Klee et al. 2004 for details). Both the upland and bottomland habitats contained
abundant Smilax spp. (greenbrier), Lonicera maackii (Rupr.) Herder (amur
honeysuckle), L. japonica Thunb. (Japanese honeysuckle), and Ligustrum
sinense Lour. (Chinese privet). Quercus nigra L. (water oak), Liquidambar
styraciflua L. (sweet gum), and Liriodendron tulipifera L. (tuliptree) dominated
both habitat types, whereas Q. alba L. (white oak) and Fagus grandifolia
Ehrh. (American beech) were abundant in the upland habitat, and Betula nigra
L. (river birch) was abundant in the lowland habitat.
Eight trapping grids (each 0.21 ha) were established in bottomland and
upland forest habitat types (n = 4 each) to quantify population abundance of
white-footed and golden mice. Each grid consisted of 12 trapping stations
established in a 2 x 6 grid pattern. Trapping stations were 10 m (± 2 m) apart.
Each station consisted of two Sherman live traps (7.62 x 7.62 x 25.4 cm each);
one trap was on a wooden platform 1.5 m high on the trunk of a tree, and the
second trap was on the ground within one meter of the base of the same tree.
Live trapping was conducted weekly from 29 March to 16 November
2001, and from 17 March to 3 November 2004. Traps were baited with black
oil sunflower seed, set before dark, and examined the following morning.
2007 C.C. Christopher and G.W. Barrett 409
Captured white-footed and golden mice were either marked by toe clipping
(ASM Animal Care and Use Committee 1998) or by ear tags for identification.
Trap-springing weights were not used as described by Bergstrom
(1986) because both species of small mammals are of similar body mass
(Christopher and Barrett 2006). Each trap was set for sensitivity at the time
of setting. It is possible, however, that some traps were less sensitive than
others. Such an insensitive trap might not be sprung until two individuals
had entered the trap.
We determined the sex, weight, reproductive condition (vaginal orifice
open or closed, testes abdominal or scrotal), and general health for each
captured animal. The date and location of capture was recorded for each individual.
Captured animals were immediately released following examination
at the site of capture. Mean weekly population abundance was estimated
by the minimum-number-known-alive (MNKA) method (Krebs 1996).
Results and Discussion
Mean weekly population abundance for both white-footed and golden
mice reached a peak in early spring and declined steadily until late autumn
both years. In 2001, the maximum mean abundance for white-footed mice per
grid (0.21 ha) was 23.1 during 22–28 April, and the maximum mean abundance
for golden mice per grid was 12.3 during 20–26 May. White-footed and
golden mice populations steadily declined to a mean of 1.5 during 11–17
November and 0.3 during 4–10 November, respectively. Similar trends were
observed in 2004 when white-footed mice mean population abundance
peaked at 34.3 during 28 March–3 April, and golden mice peaked at 6.1 during
12–27 March. Population abundance then declined to a mean abundance per
grid of 1.9 for white-footed mice and 0.3 for golden mice during early
November. Christopher and Barrett (2006) and Jennison et al. (2006) provide
details regarding population dynamics of each species during 2001 and 2004,
respectively. There were 254 individual captures of white-footed mice during
2001 and 486 captures during 2004. Golden mice were captured 121 times
during 2001, and there were 89 captures during 2004. There were also 64
double captures during 2001, and 39 double captures during 2004. Thus, there
were 103 intra- and interspecies double captures during the 2001 and 2004
trapping seasons (Table 1).
No juveniles or weanlings were included in the total number of double
captures. Of these double captures, 57.0% involved heterosexual
double captures of white-footed mice; the highest percentage of double
captures of golden mice (8.7%) was also heterosexual. This heterosexual
intraspecific combination of double captures agrees with the findings of
Getz (1972), Novak (1983), and Petersen (1975) involving double captures
of Microtus pennsylvanicus Rhoads (meadow vole); northern pygmy
and western harvest mice; and white-footed mice, respectively. However,
Feldhamer (1977) reported that 14 of 16 double captures of Microtus
montanus Baird (montane vole) were males.
410 Southeastern Naturalist Vol. 6, No. 3
The high percentage of heterosexual double captures for each species
suggests that conspecific odors in traps best accounts for this finding
(Drickamer 1984, Mazdzer et al. 1976). Wolf and Batzli (2002) noted that
adult white-footed mice were more likely to be captured in traps previously
occupied by conspecific individuals of the opposite sex than in traps previously
occupied by the same sex, especially during the breeding season. Our
findings tend to confirm this observation for white-footed mice and suggest
that golden mice may respond to trap odors in a similar manner. For example,
9 of 10 double captures of golden mice were heterosexual.
Same-sex double captures of white-footed mice were 17.5% for males
and 15.5% for females (Table 1). These data suggest lack of an antagonistic
sexual behavior for white-footed mice. The 14 interspecific double captures
of white-footed and golden mice is also evidence of lack of antagonistic
behavior between these two species. In instances of interspecific double
captures, only one golden mouse was found dead or injured. This finding
suggests a high degree of compatibility between these two small mammal
species even when confined to a single live trap. Because food resources
were abundant (e.g., water oak acorn mast crop) in our study (Christopher
and Barrett 2006), we suggest that interspecific double captures were related
to greatly reduced interference competition between these two species in the
There were significantly more double captures in 2001 (n = 64) than 2004
(n = 39; 2 = 6.07, df = 1, P < 0.05). Based on the total number of captures of
both species during both years (n = 950), one can predict (Feldhamer and
Maycroft 1992) the number of expected double captures using a binomial
distribution (p2 + 2pq + q2), where p (white-footed mice) = 0.78 and q (golden
mice) = 0.22. Although white-footed and golden mice were live-trapped
together 14 times (Table 1), this value is significantly less than the 35.02
expected (2 = 21.2, df = 2, P < 0.001); intraspecific double captures were
more frequent than expected based on this binomial distribution.
Goodpaster and Hoffmeister (1954) reported finding a white-footed mouse
nest approximately five meters from a golden mouse nest, and noted that there
appeared to be no rivalry for food or nesting sites between these two species.
Table 1. Frequency and composition of double captures of P. leucopus (white-footed mouse)
and O. nuttalli (golden mouse) during 2001 and 2004.
Composition of double capture Frequency Percentage
1 male, 1 female P. leucopus 45 43.7
2 male P. leucopus 18 17.5
2 female P. leucopus 16 15.5
1 male, 1 female O. nuttalli 9 8.7
1 male P. leucopus, 1 female O. nuttalli 8 7.8
1 male P. leucopus, 1 male O. nuttalli 4 3.9
1 female P. leucopus, 1 female O. nuttalli 2 1.9
2 male O. nuttalli 1 1.0
Total 103 100.0
2007 C.C. Christopher and G.W. Barrett 411
Christopher and Barrett (2006) document how coexistence between these
species is made possible by differential use of three-dimensional habitat space,
rather than by competition for food and nesting sites. Differences in bioenergetics
and food choices tend to confirm this observation (Knuth and Barrett
1984, O’Malley et al. 2003). These findings indicate that there exists extensive
niche overlap in time and space between these two species. In addition to the
high percentage of conspecific heterosexual double captures for each species,
likely attributed to conspecific odors in traps, perhaps sociality, rather than
exploitation or interference competition, also helps to explain the frequency of
interspecific double captures and compatibility between these two small
mammal species of similar life histories and body mass.
We thank G. Cameron, S. Castleberry, and G. Feldhamer for review of this
manuscript. We thank T.L. Barrett for manuscript preparation. We also thank J.
Chastant, C. Jennison, R. Klee, T. Luhring, A. Mahoney, K. Meeks, A. Pruett, C.
Schmidt, S. Shivers, and M. Shuman for field assistance during 2001 and 2004. This
study was funded in part by the Eugene P. Odum Professorship endowment provided
to G.W. Barrett.
ASM Animal Care and Use Committee. 1998. Guidelines for the capture, handling,
and care of mammals as approved by the American Society of Mammalogists.
Journal of Mammalogy 79:1416–1431.
Bergstrom, B.J. 1986. An analysis of multiple captures in Peromyscus, with a
critique on methodology. Canadian Journal of Zoology 64:1407–1411.
Bergstrom, B.J., and J.R. Sauer. 1986. Social traveling inferred by multiple captures:
Testing assumptions. American Midland Naturalist 115:201–203.
Blaustein, A.R., and S.I. Rothstein. 1978. Multiple captures of Reithrodontomys
megalotis: Social bonding in a mouse. American Midland Naturalist 100:376–383.
Christopher, C.C., and G.W. Barrett. 2006. Coexistence of white-footed mice
(Peromyscus leucopus) and golden mice (Ochrotomys nuttalli) in a southeastern
forest. Journal of Mammalogy 87:102–107.
Drickamer, L.C. 1984. Captures of two species of Peromyscus at live traps baited
with male and female odors. Journal of Mammalogy 65:699–702.
Dunaway, P.B. 1968. Life history and population aspects of the eastern harvest
mouse. American Midland Naturalist 79:48–67.
Evans, F.C., and R. Holdenreid. 1943. Double captures of small rodents in California.
Journal of Mammalogy 24:401.
Feldhamer, G.A. 1977. Double captures of four rodent species in Oregon. Northwest
Feldhamer, G.A., and K.A. Maycroft. 1992. Unequal capture response of sympatric
golden mice and white-footed mice. American Midland Naturalist 128:407–410.
Getz, L.L. 1972. Social structure and aggressive behavior in a population of Microtus
pennsylvanicus. Journal of Mammalogy 53:310–317.
Goodpaster, W.W., and D.F. Hoffmeister. 1954. Life history of the golden mouse
(Peromyscus nuttalli) in Kentucky. Journal of Mammalogy 35:16–27.
412 Southeastern Naturalist Vol. 6, No. 3
Jenkins, S.H., and J.B. Llewellyn. 1981. Multiple captures of Peromyscus: Age, sex,
and species differences. Journal of Mammalogy 62:639–641.
Jennison, C.A., L.R. Rodas, and G.W. Barrett. 2006. Botfly (Cuterebra fontinella)
parasitism on Peromyscus leucopus and Ochrotomys nuttalli. Southeastern Naturalist
Klee, R.V., A.C. Mahoney, C.C. Christopher, and G.W. Barrett. 2004. Riverine
peninsulas: An experimental approach to homing in white-footed mice
(Peromyscus leucopus). American Midland Naturalist 151:408–413.
Knuth, B.A., and G.W. Barrett. 1984. A comparative study of resource partitioning
between Ochrotomys nuttalli and Peromyscus leucopus. Journal of Mammalogy
Krebs, C.J. 1996. Ecological Methodology, 2nd Edition. Benjamin Cummings,
Menlo Park, CA.
Lackey, J.A., D.G. Huckaby, and B.G. Ormiston. 1985. Peromyscus leucopus. Mammalian
Linzey, D.W. 1968. An ecological study of the golden mouse (Ochrotomys nuttalli)
in the Great Smoky Mountains National Park. American Midland Naturalist
Linzey, D.W., and R.L. Packard. 1977. Ochrotomys nuttalli. Mammalian Species
Mazdzer, E., M.R. Capone, and L.C. Drickamer. 1976. Conspecific odors and
trapability of deer mice (Peromyscus leucopus noveboracensis). Journal of Mammalogy
Novak, J.M. 1983. Multiple captures of Peromyscus leucopus: Social behavior in a
small rodent. Journal of Mammalogy 64:710–713.
O’Malley, M., J. Blesh, M. Williams, and G.W. Barrett. 2003. Food preferences and
bioenergetics of the white-footed mouse (Peromyscus leucopus) and the golden
mouse (Ochrotomys nuttalli). Georgia Journal of Science 61:233–237.
Petersen, M.K. 1975. An analysis of multiple captures in several rodents from
Durango, Mexico. Journal of Mammalogy 56:703–705.
Pruett, A.L., C.C. Christopher, and G.W. Barrett. 2002. Effects of a riparian peninsula
on mean home range size of the golden mouse (Ochrotomys nuttalli) and the
white-footed mouse (Peromyscus leucopus). Georgia Journal of Science 60:201–
Sheppe, W.A. 1967. Habitat restriction by competitive exclusion in the mice
Peromyscus and Mus. Canadian Field-Naturalist 81:81–98.
Slade, N. A. 1976. Analysis of social structure from multiple capture data. Journal of
Spencer, S.R., G.N. Cameron, and W.B. Kincaid. 1982. Multiple captures of the
fulvous harvest mouse (Reithrodontomys fulvescens). American Midland Naturalist
Wolf, M., and G.O. Batzli. 2002. Relationship of previous trap occupancy to capture
of white-footed mice (Peromyscus leucopus). Journal of Mammalogy 83:728–