Urban mountain chickadees (Poecile gambeli) begin vocalizing earlier, and have greater dawn chorus output than rural males

Abstract

Vocal output during the dawn chorus is often an honest indicator of male quality, where males with greater access to food and in better condition produce more vocalizations. We compare the vocal output among male mountain chickadees living along an urbanization gradient to assess how urbanization affects male signalling. Chickadees forage in the canopy, and because urban habitats are associated with lower canopy volume, we predicted that urban habitats may offer lower food and thus lead to reduced song output. Contrary to our predictions, males in more urbanized habitats had greater vocal output. We suggest that despite decreased canopy cover, urban birds may have greater access to food in both the breeding and pre-breeding seasons due to differences in both supplementary resources and vegetation composition of urban vs rural landscapes in our area. Living in urban habitats may allow males to enter the breeding season in better condition.