A systematic review of forest bird occurrence in North American forest fragments and the built environment

Urban decision-makers typically cannot utilize empirical bird studies to create bird-friendly landscape designs because academic results are often in a format that is not easily transferable to planning. We report on the results of three systematic reviews of peer reviewed literature regarding bird occurrence in forests, forest fragments, and tree canopy in and around North American cities. Note that our reviews focused on occurrence and did not evaluate species fitness or abundance. We synthesized findings from 48 studies to create a list of 219 forest dwelling species; and for each species, we identified whether the species utilized or did not utilize forest fragments during the breeding season; whether migrant species utilized forest fragments as stopover sites during the migration season; and whether the species utilized residential areas with trees during the breeding and migration seasons. We found that some interior-forest specialists, which generally require large tracts of forest to breed successfully, use small urban and rural forest fragments as well as tree canopy within suburban residential areas as stopover sites during migration seasons. This supports previous literature findings that habitat requirements for migrants, including interior-forest specialists, may differ between breeding and migration seasons. The synthesized bird list will allow built environment professionals to identify bird species that can and cannot use treed habitat in fragmented rural and urban landscapes, and we have created a planning tool for conserving avian habitat.