One of the most common blackbirds in North America, the Brewer's blackbird is named for renowned ornithologist Thomas Mayo Brewer (1840-1880). These birds have a uniformly colored plumage and iridescent gloss that gives them a unique sheen in bright light, a key to easy identification.
- Bill: Straight, black, thin conical shape, sharply pointed
- Size: 9-10 inches long with 15-inch wingspan, small head, long tail
- Colors: Black, brown, iridescent, green, purple, gray, yellow
- Markings: Dimorphic species. Males are black overall with a glossy iridescent wash that shows purple on the head, neck and breast and greenish or bluish on the wings in bright sunlight. The pale yellow eye with its dark iris stands out starkly in the dark face. Females are a dull gray-brown overall and slightly paler brown on the underparts, though the wings and tail may show a faint green iridescent sheen in good light. Most females have dark brown eyes, but a small proportion will have lighter colored eyes similar to the male's bright eyes. For both genders, legs and feet are dark.
Juveniles look similar to adult females, but young males will have a stark black and brown patched appearance when molting into their adult plumage.
Insects, caterpillars, grain, fruit (See: Insectivorous)
Habitat and Migration:
These blackbirds prefer open scrub habitats, such as riparian areas, agricultural field edges and rural development near livestock, though they are also readily found in urban and suburban areas such as parking lots, parks and picnic areas. Brewer's blackbirds are year-round residents in much of western North America, from the southern tip of British Columbia and coastal California to most of Oregon, Nevada and Utah, as well as northeastern Arizona and central Colorado.
In summer, these birds have a much wider breeding range that expands north to include most of southern and central Canada, the Great Plains and Midwest as far east as Michigan. In winter, northern populations migrate and the winter range for these neotropical migrants extends across the central and southern United States as far as western regions of Florida and Georgia, as well as Mexico.
Vagrant sightings are regularly reported much further east than expected, particularly during migration periods.
These birds have a harsh, raspy "chek" call note, and their typical song is a short mechanical squeak, similar to the rusty squeak of a child's swing or screen door.
While these birds do pair off during the breeding season, they are gregarious and congregate in large flocks during migration and winter, often mixed with other blackbird species for foraging and roosting. They forage almost exclusively on the ground, walking with a strut-like pace with their chest thrown out and head slightly bobbing before bending to pick at insects.
These birds are loosely colonial and may nest in small to medium-sized groups, though individual pairs do not assist with one another's nests. The female builds a cup-shaped nest of grass and sticks stuck together with mud or manure and lined with finer grasses, fur or rootlets. The nest is positioned up to 150 feet above the ground. The oval-shaped eggs are a light green or gray-green color and may be marked with brown or gray splotches, but there is much variation among overall patterns and exact color hues.
There are 3-7 eggs laid per brood, and 1-2 broods is typical for each pair during the breeding season. The female parent incubates the eggs for 12-14 days, and both parents feed the altricial young for an additional 13-15 days until they are ready to leave the nest.
Brewer's blackbirds have been occasionally recorded as hybridizing with great-tailed grackles where the two species' ranges overlap.
Attracting Brewer's Blackbirds:
These birds are not common guests in backyards but can be tempted to visit with ground-feeding areas or low platform feeders that offer cracked corn or mixed birdseed. Minimizing insecticide use and providing some scrub cover can also make a backyard more appealing to Brewer's blackbirds.
In the past, Brewer's blackbirds were occasionally persecuted as agricultural pests, though they often ate far more insects than grain or seeds and could actually be a help to farmers. Today, these birds are abundant and are not threatened or endangered, despite being frequent hosts to brood parasites such as brown-headed cowbirds.