The Influence of Environmental Cues and Anthropogenic Activity on Roost Departure Times in the Northwestern Crow (Corvus caurinus)

Abstract

ABSTRACT While communal roosting is fairly common in animals, the costs, benefits, and proximal factors influencing this behavior are poorly understood. Moreover, many species with communal roosting that have been studied to date have a strong association with humans; however, there have been few formal tests of how human activity might influence roosting behaviors. We studied roosting activity in the Northwestern Crow (Corvus caurinus) within a highly urbanized setting. Specifically, we were interested in whether variation in anthropogenic noise influenced departure times of crows from their roosts. We tested this by comparing roosting activity between days that differed in the extent and timing of automobile noise. We also tested whether other environmental factors (i.e., sunrise time and precipitation) might also influence roost departure times. We found that morning departure was later on rainy mornings and was largely correlated with sunrise time, consistent with previous studies of other species. We...