As humans continue moving to urban areas, there is a growing need to understand the effects of urban intensification on native wildlife populations. Forest species in remnant habitat are particularly vulnerable to urban intensification, but the mechanisms behind these effects are poorly understood. Through generalized linear modeling and multi-model inference, I used occurrence data for 58 forest species derived from 16,541 forested point counts from the Second Pennsylvania Breeding Bird Atlas, urbanization intensity and other landscape metrics derived from circular radii of ten different sizes surrounding count locations, and species trait data to determine the role that biological traits play in forest birds’ response to urbanization intensity and scale of effect. Of the twenty species traits analyzed, clutch size, fledglings per nest, frugivory, and sedentarism had positive relationships with species’ responses to urbanization intensity, with fledglings per nest and sedentarism being the most influential predictors. Cavity nesting, clutch size, flock size, frugivory, granivory, omnivory, and wingspan had positive relationships with scale of effect, with frugivory being the most influential predictor. This research suggests that frugivorous, sedentary forest bird species with large reproductive outputs are the most equipped to survive in urban areas, and that species’ dietary habits have the greatest impact on the size of landscape they require. These findings can be used to inform forest bird biodiversity and land conservation programs in urban areas.
