Most facts taken from Peterson's Western Birds and Western Birds' Nest Field Guides. Larger, fatter than a sparrow. Head, throat, wings and tail are bright blue. Chest and part of back is rust red. The female is paler in color with a grayer throat and belly.
Juveniles are grayish with some blue in the wings and tail, speckled and lacking rust color.
A short pew or mew. Chattering note when communicating with each other or as a distress call. Birders have observed Western bluebirds at suet feeders. In a natural cavity, building cavity or nest box. Nest is made with grasses and forb stalks.