Two medium-sized blackbirds closely resemble one another, Brewer's Blackbird and the Rusty Blackbird (Euphagus carolinus). In winter they may be found in many of the same regions, but Brewer's Blackbird frequents grassy areas and the Rusty swampy woods. It is normally seen in open areas and on lakeshores. Brewer's gives a strong, rough whistle or a "whirring gurgle"; the Rusty calls "tickle-EE", sounding like a mechanical joint that needs oiling.
Licensed under Public Domain via Wikimedia Commons