THE FORAGING ECOLOGY OF THE GRAY RAT SNAKE (ELAPHE-OBSOLETA-SPILOIDES) - III - SEARCHING FOR DIFFERENT PREY TYPES IN STRUCTURALLY VARIED HABITATS

Dietary generalists foraging for prey inhabiting different microhabita ts may encounter different levels of structural complexity. We examine d the effect of variation in prey type on the predation success and be haviors of the semi-arboreal gray rat snake (Elaphe obsoleta spiloides ) foraging in structurally varied habitats. Individual snakes searched for contents of arboreal birds' nests or for small rodents in enclosu res that simulated a bottomland hardwood forest habitat with one of fi ve levels of vegetation density. Latency to prey capture was lower whe n the snakes were searching for small rodents than when they were sear ching for birds' nests, and lower for male snakes than for females. Ge nerally, snakes were most successful when searching for prey in enclos ures with low levels of structural complexity, and experienced decreas ed predation success in barren or highly complex habitats. Habitats wi th low levels of structural complexity may offer the snakes concealmen t from predation while not obscuring their perception or pursuit of pr ey. Of behavior durations measured in the trials, over 95% concerned 6 of the 20 behaviors described, and 3 of these occurred more often tha n the others, regardless of variation in the structural complexity of the habitat. Foraging gray rat snakes exhibited behaviors characterist ic of active and ambush foraging strategies that increased their preda tion success on different prey types in the varied environments.