Snag Availability and Preference of Cavity-Nesting Species in Philadelphia Urban Parks

Thumbnail Image
Degree type
Graduate group
Environmental Sciences
Physical Sciences and Mathematics
Grant number
Copyright date
Raezer, Angelique Noëlle

In addition to habitat destruction and fragmentation, the removal of standing dead trees, known as snags, for safety and aesthetic purposes has increased pressure on cavity-nesting species to find resources for shelter, food, and nesting especially in isolated urban forest islands. Forested, riparian habitat in two Philadelphia urban parks (Wissahickon Valley Park and Cobbs Creek Park) was monitored for cavity nesting in four 0.5-acre circular sampling plots to determine their habitat suitability. Bird presence and nests were recorded during the nesting season of mid-April through mid-July in 2021 and 2022. Habitat assessments were completed in November 2021 and April 2022. Dead or dying trees (snags), as well as living trees with cavities, were also recorded and categorized by species and diameter at breast height. Across all plots, the most abundant cavity-nesting species in 2021 and 2022 was the Red-bellied Woodpecker (Melanerpes carolina) while Plot C1 had the most standing deadwood. Information from this study could be used to inform management of forest islands and urban parks through nesting box programs, snag maintenance, and greater conservation efforts to improve biodiversity. Despite forest islands such as Cobbs Creek Park and Wissahickon Valley Park being adversely affected by a lack of resources, they still offer crucial habitat for many bird species, especially cavitynesters. However, many forest islands could improve through nesting box programs, snag maintenance, and biodiversity conservation. Therefore, it is important to work on conserving the remaining woodlands of the east coast, reconnecting isolated patches where possible, and encouraging the overall health and biodiversity of these forests so that they can support and encourage healthy bird populations with an emphasis on the less well-known cavity nesting species that have more limited nesting opportunities.

Date of degree
Date Range for Data Collection (Start Date)
Date Range for Data Collection (End Date)
Digital Object Identifier
Series name and number
Volume number
Issue number
Publisher DOI
Journal Issue
Recommended citation