Ultimo aggiornamento Domenica 21 Novembre 2010 22:24
Habitat structural complexity may affect foraging success as predators either experience the greatest level of foraging success at low levels of habitat structural complexity, or at an optimal level of complexity above or below which foraging success decreases. I examined the effects of variable habitat structural complexity on the predatory success of a semi-arboreal species of snake (Elaphe obsoleta spiloides) foraging for artificial nests of Northern Bobwhite Quail (Collinus virginiaus) eggs. Individual snakes searched for arboreally-placed nests in large enclosures designed to simulate one of five treatment levels of vegetation density. Latency to prey capture (a measurement of foraging success) and snake behaviours were recorded on video tape.
Grey rat snakes were least proficient at capturing prey in enclosures containing high levels of vegetation density, and experienced the greatest level of foraging success at a low level of vegetation density.
Male individuals generally took less time than females to successfully encounter the nest.
Frequencies and durations of specific behaviours varied as a function of vegetation density. We suggest that simple habitats allow Gray rat snakes to visually locate arboreal nests while still affording some level of protection against predation; structurally complex habitats may obscure such nests from Gray rat snakes foraging from the ground.