Nonintrusive acoustic identification of hermit thrush (Catharus guttatus) individuals

Abstract

From mid-April well into the summer, the secretive hermit thrush (Catharus guttatus) can be heard singing throughout the woodlands of Nova Scotia. Its song is distinctive, beginning with a clear introductory note followed by a flurry of flutelike body notes, often cascading and reverberant in character. Despite this fine display of avian virtuosity, few studies have been reported that probe the differences between the calls, songs, and repertoires of individuals. From April 2003 to May 2006, over 3000 songs from several birds were recorded using digital video cameras at study sites in and around the city of Halifax, Nova Scotia. The only birds recorded were those in close proximity to roads and trails. None of the birds were marked, banded, or deliberately disturbed in any way. Although the study birds remained hidden from view most of the time, in the few instances where the birds perched in the open, their behaviors while singing were captured on videotape. All of the birds were readily distinguishable from each other as no two individuals had a single song in common. The most significant finding was that individuals could be reidentified acoustically after 1 week, 3 months, and 1 year had elapsed.