FEEDING NEOPHOBIA AND ECOLOGICAL PLASTICITY - A TEST OF THE HYPOTHESIS WITH CAPTIVE SPARROWS

The hypothesis that quantitative differences in neophobia underlie varitaion in ecological plasticity was tested by comparing feeding responses of wild-caught immature song, Melospiza melodia, and swamp, M. georgiana, sparrows in captivity. The song sparrow is a habitat generalist and good colonizing species, while the swamp sparrow specializes on marsh habitats. As predicted by the neophobia hypothesis, captive swamp sparrows showed a greater hesitancy to feed in the presence of a variety of novel objects than did song sparrows. Swamp sparrows made significantly more approaches to the food source without feeding when a novel object was present. There was a consistent difference in latency among individuals within each species. Habituation reduced latencies in the most neophobic sparrows, but sometimes almost a week of constant exposure was required before swamp sparrows fed without hesitation. © 1990.