Post-breeding survival of adult and hatch-year Bank Swallows (Riparia riparia) in the Great Lakes region: a radio telemetry study

The post-breeding period poses significant threats to newly fledged birds due to predation, starvation, exposure to inclement weather, and collision risk prior to their first southward migration. I used automated radio telemetry to track 100 adult and 100 hatch-year Bank Swallows (Riparia riparia) in the Great Lakes ecoregion during the 2021 post-breeding period. Additionally, 74 hatch-year birds tracked in 2018 by Mitchell et al. were included. In 2021, daily apparent survival probability was higher for adults compared to hatch-years; we estimated that ~10% of hatch-year birds die within two weeks post-fledging but high rates of tag loss in adults and hatch-year birds precluded accurate estimation. Among hatch-year birds, there was some support that daily recapture probability was higher for those from natural lakeshore colonies compared to those from artificial aggregate pit colonies, but this could be due to inland locations of most aggregate pit colonies. Apparent survival among hatch-year birds was higher in 2018 than in 2021 and 2018 was also a drier year. Results suggest that colony type and age can affect survival and recapture during the post-breeding period.