Date of Award


Document Type

Honors Thesis (Colby Access Only)


Colby College. Biology Dept.


Herb Wilson

Second Advisor

Jeff Wells


Monitoring flight calls of nocturnal migrants is a valuable tool for detecting patterns of avian migration. In conjunction with radar, morning observations, and other visual methods, acoustic monitoring of migration yields information about the numbers and types of migrants moving through an area. However, there is a general assumption that flight calls indicate an early morning peak in migration, while visual monitoring indicates a peak in the hours after sunset. In this study I use flight call data collected in Déline, NW Territories, and Lesser Slave Lake, Alberta to investigate and compare nightly and seasonal distributions of nocturnal flight calls during post-breeding migration. The results indicate that across a season the nightly distributions of flight calls at the two sites are distinct from one another. Furthermore, within each site nightly distributions appear to be very similar, though dates closer to together are usually the most similar. Thus, the results indicate that flight call distributions are related to local factors, and extrapolating information from one site may be uninformative or even misleading.


Full-text download restricted to Colby College campus only.


nocturnal flight calls, avian migration, migration patterns, endogenous cues, wind turbines