Human Disturbance and Nestling Behavior in Black-Crowned Night Herons

Abstract

The effects of human disturbance on Black-crowned Night Heron (Nycticorax nycticorax) nestling behavior were studied at the Dead Neck Island (Barnstable Co., Massachusetts) heronry in June and July, 1980. Nestling response to disturbance was compared between three-week old chicks that had been regularly handled since hatching, and control nestlings. Every control nestling moved some distance from the nest during the observation period, whereas all experimental chicks remained in the nest. Mean distance traveled by control birds was 1.0 m (range 0.2 to 3.6 m). Experimental chicks became habituated to frequent handling, whereas a single, intense disturbance elicited escape behavior in control nestlings. Weights of three-week old control and experimental nestlings were not significantly different. Repercussions of altered chick behavior in experimental animals are discussed and results compared to other studies.