Adult males have black plumage with an iridescent purple head and neck and glossy bluish-green highlights on the rest of the body.

Their breeding habitat is open and semi-open areas, often near water, across central and western North America.

[5] When Brewer's blackbirds identify threats, such as hawks or even humans, they dive towards them and emit an alarm call.

Brewer's blackbirds have been seen cleverly following vehicles plowing fields, eating the churned up insects.

[5] They forage in shallow water or in fields, mainly eating seeds and insects, some berries.

[5] In marshy areas, they are known to stand on aquatic plants and wade in shallow water to catch insects.

The same pair tends to reunite for mating season[6] and both parents take a role in feeding.

[5] During mating, male Brewer's blackbirds will puff up their feathers while simultaneously spreading out their wings and tail to look as large as possible.

They are built by the female in a cup-like shape and are bonded with mud or other securing substances.

[6] Brewer's blackbird (Euphagus cyanocephalus) is protected in the United States under the Migratory Bird Treaty Act of 1918,[10] however exceptions are granted under 50 CFR part 21 (2014) [11] for animals committing or about to commit depredations upon ornamental or shade trees, agricultural crops, livestock, or wildlife, or when concentrated in such numbers and manner that they are a health hazard or other nuisance.