Identifying migratory pathways used by Rusty Blackbirds breeding in Southcentral Alaska

We placed light-level geolocators on 17 Rusty Blackbirds (Euphagus carolinus) in 2009 to track their migrations from nest sites near Anchorage, Alaska to wintering areas and back. We recaptured three of these birds in 2010 and found they departed breeding areas during the first half of September, spent 72–84 days migrating to overwintering areas, but only 16–30 days on their northward migration to Alaska. Birds took similar Central Flyway routes on southward and northward migrations, which were not previously described for this species. The birds used a series of stopover sites across the prairie region from southern Saskatchewan to Iowa over a 4 to 5 week period on their southward migration to wintering areas that spanned from South Dakota to northern Louisiana. We found upon recapture in 2010, the geolocator attachment harnesses had abraded the surrounding feathers on all three birds. This coupled with the low return rate (18%) for instrumented birds indicates a better harness method must be developed before this technology is more widely used on Rusty Blackbirds

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