Evaluation Of Nocturnal Flight Calls As A Useful Tool In The Study Of Avian Migration

Evaluation of Nocturnal Flight Calls as a Useful Tool in the Study of Avian Migration

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.

Proceedings RMRS.

Strategies for Bird Conservation

This volume represents a compilation of papers presented at the 3rd International Partners in Flight Workshop held October 1-5, 1995, at the Grand Hotel in Cape May, NJ. The title of the workshop was 'Partners in Flight Conservation Plan: Building Consensus for Action.' Manuscripts have been available on-line at the Cornell Laboratory of Ornithology web site (http://birds.cornell.edu/pifcapemay) since the year 1999, and the majority of them have been updated recently to reflect knowledge available by the 2000 publication date. The volume is divided into seven sections that range from general planning considerations to a case study in bird conservation planning. References from all papers are compiled in a single 'References' section at the end of the volume.