General Description
Rusty Blackbirds are rare winter visitors to Washington. We are most likely to see these birds in non-breeding season, in the plumage that gives them their name. Non-breeding males are black with rusty edges on their feathers. Females are lighter brown all over, with buff-colored mottling and gray rumps. Rusty Blackbirds are fairly slender birds with long wings and tails. Both sexes have yellow eyes in all plumages. During breeding season, males are black with slightly iridescent purple-green plumage, and females are dull brown. Male Brewer's Blackbirds look similar, but lack the rusty edging on their feathers, are glossier during the breeding season, and have longer tails.
Habitat
Rusty Blackbirds nest in spruce bogs and other wet, forested areas throughout Canada and Alaska. They often nest in small clear-cuts or openings caused by natural disturbances. During migration and winter, they inhabit wooded swamps, but forage in open areas and cattle feedlots. They typically prefer wooded areas more than do other blackbird species.
Behavior
In Washington, Rusty Blackbirds may be mixed in with flocks of Brewer's or Red-winged Blackbirds. They walk along the ground while foraging, often turning leaves over to expose food, and will feed at pond or wetland edges, sticking their heads underwater to take food from the bottom.
Diet
Rusty Blackbirds eat many aquatic insects and other small invertebrates. They also eat seeds and waste grain, especially during winter.
Nesting
Sometimes Rusty Blackbirds breed in small, loose colonies, but isolated, monogamous pairs are the norm. Nests are usually close to or directly above the water, in dense trees or shrubs. The female builds a bulky open cup with a lichen foundation, a body of grass, twigs, and decaying plant material, and a fine grass lining. She incubates 3 to 5 eggs for about two weeks and then broods the young after they hatch. Both sexes feed the young, which leave the nest about 11 days after hatching. They cannot fly when they leave the nest, but learn within a few days.