Electronic Thesis and Dissertation Repository


Master of Science




Hobson, Keith A.


For migratory songbirds, population dynamics are primarily influenced by juvenile or first year survival, but survival between fledging and fall migration is particularly important. Unfortunately, our knowledge of this post-fledging period is largely limited due to the difficulty of tracking juveniles outside the nest. For this thesis, I used automated radio telemetry to track the survival and post-fledging movements of 216 juvenile Barn Swallows (Hirundo rustica) from fledging up until departure for autumn migration in 2016-2017. Average apparent survival was 42% for both broods and nestlings in better body condition had higher survival. Nestlings from second broods migrated 21 days younger and moved less overall during the post-fledging period but had significantly higher daily post-fledging movements suggesting they might be trying to compensate for their shorter time near the breeding grounds. My results suggest that the post-fledging period is a critical period of survival and exploration for juvenile Barn Swallows.