Tracking Northern Saw-Whet Owls
Tracking Northern Saw-whet Owls (Aegolius acadicus) along the coast of Maine
Migratory stopover sites play a critical role in sustaining and maintaining migratory bird populations.
The unexpected capture of these 80-gram migratory owls last fall - on the island of Isle au Haut in the Gulf of Maine - inspired an investigative effort that spanned the coast of Maine in October of this year.
2010 northern saw-whet owl capture sites. Click map to enlarge.
BRI biologists stationed throughout coastal mainland and island sites in Maine captured 253 northern saw-whet owls on their journey south. That migratory owls fly over open water and use islands as stopover sites during migration is a previously undocumented phenomenon in the Gulf of Maine.
Owls that are banded and then recaptured, such as several saw-whet owls banded in Quebec this year that were recaptured on Monhegan and Small Point, indicate that Maine saw-whet populations are part of a larger, international population of migratory owls.
BRI's findings indicate that coastal habitats and islands may be important stopover areas for northern saw-whet owls during migration.
Aging a second year owl using UV lightÂ
(photo by Tony Oppersdorff)
Season totals and owls caught per unit of effort for all sites
SIGNIFICANCE TO POLICY
BRI's ongoing studies of coastal migration patterns for nocturnal and diurnal raptors provide critical information about the numbers, timing, and species of birds migrating offshore. These types of data can inform future siting decisions for marine-based wind power facilities and other development.
MBAN, BRI's Maine Biomonitoring and Assessment Network, aims to increase our understanding of wildlife habitat use and potential threats to wildlife populations. For more information about this effort, please contact BRI's Kate Williams.
The two-page report summary can be downloaded here.