Reproductive Cycles and Temporal Variation in Fecundity in the Black Swamp Snake, Seminatrix pygaea

-We studied the reproductive ecology of female black swamp snakes (Seminatrix pygaea) at Ellenton Bay, South Carolina, from 1983-1987. Females followed a Type I reproductive cycle, with rapid follicular growth in the spring, ovulation in June, and parturition in early August. There was no evidence of multiple clutches but most females were reproductively active in all years. Mean brood size for 70 females was 8.0 (range = 4-15) offspring, and brood size was positively related to maternal body size. Variability in reproductive traits was low. Despite a severe decrease in food availability in the last year of the study, we found no significant variation in mean brood size or proportion of females gravid among years, in contrast to studies on most other species of snakes followed for more than 2 yr. However, the relationship between brood size and female size differed among years.