The mountain bluebird (Sialia currucoides) is a medium-sized bird weighing about 30 g (1.1 oz) with a length from 16–20 cm (6.3–7.9 in). They have light underbellies and black eyes. Adult males have thin bills and are bright turquoise-blue and somewhat lighter underneath.
In open parklands of the American West, brilliant blue-and-rust Western Bluebirds sit on low perches and swoop lightly to the ground to catch insects. Deep blue, rusty, and white, males are considerably brighter than the gray-brown, blue-tinged females.