In general Bluebirds are not difficult to identify. The Western Bluebird is a resident of the Trans Pecos of Texas and points further west. The Eastern Bluebird occupies the eastern two-thirds of the state and wanders west during winter. The Mountain Bluebird breeds in the American West and wanders into west Texas and the Panhandle in winter.
The primary identification issue is to separate Eastern & Western. Three areas of plumage can be used to distinguish the Eastern and Western: 1) the back & scapulars, 2) the throat & sides of neck, and 3) the belly. The Eastern has an all blue back & scapulars; the blue cheek contrasts with the rufous sides of neck & throat; and the belly is white. On the Western the upper back and scapulars are varying shades of rufous, gray and blue; the throat & sides of neck are deep blue, seeming to form a hood over the head and neck; and the belly is gray or blueish gray, and sometimes marked with blue. The Mountain is almost entirely a beautiful shade of sky blue. These field marks are highlighted in the schematic below. Females of all 3 species differ from the males primarily in the intensity of the colors: the field marks to focus on are the same, but more washed out, less vivid.
Eastern Bluebird
Western Bluebird
Mountain Bluebird
