Spatial Distribution and Demographic Patterns of the Northern Saw-whet Owl (Aegolius acadicus)

• Eli Hevalow, Wildlife Ecology and Conservation, University of Delaware

• Jeffrey Buler, Entomology and Wildlife Ecology, University of Delaware

I analyzed capture and recapture data of the Northern Saw-whet Owl (Aegolius acadicus) to understand spatial distribution patterns across different demographic groups. I used a comprehensive dataset from the USGS Bird Banding Lab (BBL), which includes capture and recapture records from 1960 to 2023 across the United States and Canada, to visualize these patterns. Data processing and analysis were conducted using R Studio and QGIS, resulting in the creation of four distribution maps correlating with various sex and age combinations. I found significant disparities in capture frequencies between male and female owls, highlighting a need for further investigation. Female individuals are captured in far greater numbers compared to males across North America. To address this knowledge gap, I am collaborating on additional banding efforts in western Maryland, where breeding populations are present. Employing the audio-lure capture technique developed by Erdmen and Brinker (1997), I successfully captured and tagged owls. Each owl was sexed, aged, weighed, and equipped with both a radio telemetry nanotag and a USGS leg band. The nanotag codes were subsequently registered with the Motus Wildlife Tracking System network, allowing for the monitoring of owl movement patterns across North America and facilitating future data interpretation.