We examined the responsiveness of adult gray rat snakes to avian prey in enclosures that simulated natural habitat conditions. Subjects searched for arboreal nest contents in the presence or absence of a bird model flown so as to simulate avian provisioning behavior. In the absence of the model, gray rat snake latency to capture prey was over 92 % greater than when searching for nest contents with the model. Snakes responded to model flight by turning their heads in the direction of its movement. We conclude that gray rat snakes perceive relatively distant visual cues from prey, and that nest provisioning (activity localized around a nest) may facilitate snakes correctly choosing to ascend trees that contain active nests and ignoring those that do not.
Cooper, Robert J. and Mullin, Stephen J., "The Foraging Ecology of the Gray Rat Snake (Elaphe Obsoleta Spiloides)-Visual Stimuli Facilitate Location of Arboreal Prey" (1998). Faculty Publications. Paper 120.