92 
Rose, Everton, Stankavich, and Walke 
the least shrew, Cryptotis parva parva (Say); the marsh rice rat, 
Oryzomys palustris palustris (Harlan); the hispid cotton rat, Sigmodon 
hispidus virginianus Gardner; the woodland vole, Microtus pinetorum 
scalopsoides (Audubon and Bachman); and the house mouse, Mus 
musculus L. Between 26 and 44 individuals each were trapped of S. 1. 
fisheri, O. n. nuttalli , M. p. nigrans, and S. c. helaletes. Peromyscus g. 
gossypinus , one of four most common small mammals in the early 
studies, was absent. 
Combining the data from the three studies, 301 mammals of 12 
species were taken from 12 nonforested study grids (Table 2), compared 
with 58 specimens of four species from seven forested sites. Trapping 
efforts in the two habitat types were not comparable; 79.5% of the 
64,653 trap-nights were conducted on nonforested grids. Nevertheless, 
the catch rates of 5.857 and 4.376 individuals per 1,000 trap-nights were 
similar. The nonforested sites included wet grassland dominated by M. 
p. nigrans , dry grassland dominated by R. h. humulis , and young pine 
plantations and regenerating forest up to 15 years old dominated by S. 
1. fisheri , B. brevicauda, and S. c. helaletes. Habitats with young trees 
and plentiful grasses frequently yielded the greatest numbers of individuals 
and species. The mature forests were mostly red maple and black gum, 
which predominate throughout the Dismal Swamp, but one forest site 
also had numerous loblolly pines, Pinus taeda, indicating drier conditions 
and a slightly higher elevation. 
Although live and pitfall trapping yielded comparable numbers of 
individuals (Table 1), the capture efficiencies of these methods differed 
substantially. Expressed as a catch rate per 1,000 trap-nights, live 
trapping was more than three times as efficient (11.962 vs. 3.454) as 
pitfall trapping (Table 3). Capture efficiencies were comparable only for 
B. brevicauda and M. p. scalopsoides , although the sample size is 
exceedingly small for the latter species. The only other species taken by 
pitfall trapping at even half of the catch rate of live trapping was S. c. 
helaletes. Sorex l. fisheri and C. p. parva were taken only with pitfall 
traps, whereas O. p. palustris, S. h. virginianus, and M. musculus (one 
or two individuals of each) were live-trapped only. Interestingly, for the 
arboreal mice, the catch rate using nest boxes was two or three times 
greater than that using pitfall traps (Table 3), and for P. 1. leucopus, the 
nest box was slightly less than half as efficient as the live trap (0.45 vs. 
1.133 per 1,000 trap-nights). 
These studies nearly double the amount of information about small 
mammals in the Dismal Swamp (Table 4). The earliest studies (sum- 
marized in Handley 1979) focused heavily on forested sites, so the 
finding that P. leucopus and O. nuttalli (both arboreal) and the litter- 
dwelling B. brevicauda were the most common mammals is not surprising. 
