The Mountain Bluebird, Sialia currucoides, is a medium-sized thrush.
Adults have thin bills. Adult males are bright blue, somewhat lighter underneath. Adult females have duller blue wings and tail and a grey breast, grey crown, throat and back.
Their breeding habitat is open country across western North America, including mountain areas, as far north as Alaska. They nest in cavities or in nest boxes. In remote areas, these birds are less affected by competition for natural nesting locations than the other bluebirds.
Northern birds migrate to the southern parts of the range; southern birds are often permanent residents. Some birds may move to lower elevations in winter.
These birds hover over the ground and fly down to catch insects, also flies from perch to catching them. They mainly eat insects and berries. They may forage in flocks in winter.