54 David Scott 



by Edgren (1961) for the Delmarva Peninsula population of H. platy- 

 rhinos. This difference suggests a change in gene frequency of the 

 "blotch" allele(s), possibly owing to founder effect and the genetic isola- 

 tion of the island hognose population, or perhaps a change of selective 

 pressures in an island environment. 



Most of the 72 captures were made from early to middle morning. 

 Only five snakes were captured in late afternoon (1700 to 1930), and 

 none were found on the five night searches. Substrate temperature 

 ranged from 24 °C to 39 °C for 52 captures. Snakes appeared to be 

 most active when substrate temperature was 32 °C to 35 °C (N = 22). 



The data were grouped into early and late summer captures of 

 adults (males > 36.0 cm, females > 40.0 cm SVL) to test whether sexes 

 differed in their summer activity patterns. Seventeen adult males and 8 

 adult females were captured in early summer (prior to 8 July), and 1 1 

 males and 14 females in late summer. These proportions were tested 

 using a binomial test of proportions (Lewis 1966), which tended to indi- 

 cate differences in activity (U = 1.76, p < 0.08). In addition, for the 

 period 1 1 June to 12 September, adult males had a median capture date 

 of 23 June. The median for females was a month later (23 July). Nine of 

 the 10 largest females were captured after 22 July. Females in this popu- 

 lation probably laid their eggs in late June or early July, assuming an 

 incubation period of 45 to 55 days (Piatt 1969). In contrast to Piatt's 

 study, in which few adult females were captured after laying eggs, 

 females on Assateague Island appeared to be most active after oviposi- 

 tion. Females were less active early in the summer when they were 

 gravid, as has been reported for other species (Jackson and Franz 1981, 

 Shine 1979). 



ACKNOWLEDGMENTS.— I thank J. W. Gibbons, J. Congdon, S. 

 Morreale, R. Semlitsch, T. Lamb, and C. Vincent for comments on the 

 manuscript. J. Hoover and R. Schneider assisted with field work. This 

 research was supported by a grant from the U.S. Fish and Wildlife Ser- 

 vice to R. D. Dueser and W. E. Odum of the University of Virginia. 

 Manuscript preparation was aided by Contract EY-76-C-09-0819 between 

 the U.S. Department of Energy and the University of Georgia (Institute 

 of Ecology). 



LITERATURE CITED 

 Conant, Roger. 1975. A Field Guide to the Reptiles and Amphibians of 



Eastern and Central North America. Houghton Mifflin, Boston. 

 Corrington, John D. 1929. Herpetology of the Columbia, South Carolina 



region. Copeia 1929(72):59-83. 

 Duellman, William E., and A. Schwartz. 1958. Amphibians and reptiles of 



southern Florida. Bull. Fla. State Mus. 3(5): 181-324. 



