Tricolored Blackbird

Overview

The tricolored blackbird (Agelaius tricolor) is a passerine bird of the family Icteridae. Its range is limited to the coastal areas of the Pacific coast of North America, from Northern California in the U.S. (with occasional strays into Oregon), to upper Baja California in Mexico.
This highly social and gregarious bird forms the largest colonies of any North American landbird, with a single breeding colony often consisting of tens of thousands of birds.
The common name is taken from the male bird's distinctive white stripes underneath their red shoulder patches, or "epaulets", which are visible when the bird is flying or displaying.

Summary from Wikipedia, available under CC BY-SA 4.0.