Measurements:[2] The male is easily recognized by its bright blue head and back (lighter than the closely related indigo bunting), its conspicuous white wingbars, and its light rusty breast and white belly.

The color pattern may suggest the eastern and western bluebirds, but the smaller size (13–15 cm or 5–5.9 inches long), wingbars, and short and conical bunting bill quickly distinguish it.

The song is a high, rapid, strident warble, similar to that of the indigo bunting but longer and with less repetition.

On the Pacific coast their breeding range extends south to extreme northwestern Baja California.

Their habitat is brushy areas and sometimes weedy pastures, generally well-watered, and sometimes in towns.