Meeting Abstract

P3.166  Tuesday, Jan. 6  Behavioral responses of an endangered and a common bird to disturbances at the nest GLASSMAN, L W*; BUTLER, L K; ROMERO, L M; Tufts University; Tufts University; Tufts University laura.glassman@tufts.edu

Disruption of breeding activities due to human disturbance is commonly blamed for the decline of many animals around the world. However, indirect effects of human activity in breeding habitat are rarely separated from direct effects of humans degrading and destroying breeding habitat. We studied the behavioral responses of an endangered songbird, the Black-capped Vireo (Vireo atricapilla), to a human sitting or standing 1-2 meters from active nests. We compared responses of Black-capped Vireos to responses of their common and widespread congener, the White-eyed Vireo (V. griseus). Both species build cup-shaped nests hanging from the tips of branches of trees and bushes 1-2 m above ground. Because this exposed nest style permits adults to easily detect and escape from nest-directed threats, we predicted that adults would rapidly habituate to a human at the nest, as evidenced by increased willingness to approach the nest, increased willingness to incubate eggs or brood nestlings, and decreased alarm behaviors during 30-minute disturbances repeated over several days. We also compared willingness to incubate or brood during human disturbance to willingness to do so during a simulated predator threat or a novel object placed near the nest. If mild forms of human activity during the breeding season are a cause of population decline in Black-capped Vireos, then Black-capped Vireos should habituate to disturbances more slowly than White-eyed Vireos. Our study illustrates how sensitivity to mild forms of human activity may contribute to the decline of a migratory songbird.