Male Mountain Bluebird (Sialia currucoides) with food at the nest, Yellowstone National Park, Wyoming, United States of America, North America

Female mountain bluebird (Sialia currucoides) with an insect, Yellowstone National Park, Wyoming, United States of America, North America

Female mountain bluebird (Sialia currucoides) with a caterpillar, Yellowstone National Park, Wyoming, United States of America, North America

Male mountain bluebird (Sialia currucoides), Mount Evans, Arapaho-Roosevelt National Forest, Colorado, United States of America, North America

Mountain bluebird (Sialia currucoides) with a grub, Yellowstone National Park, Wyoming, United States of America, North America

Female Mountain Bluebird (Sialia currucoides) with food at the nest, Yellowstone National Park, Wyoming, United States of America, North America

Mountain bluebird (Sialia currucoides) pair at their nest, Yellowstone National Park, Wyoming, United States of America, North America

Male mountain bluebird (Sialia currucoides), Yellowstone National Park, UNESCO World Heritage Site, Wyoming, United States of America, North America

Mountain Bluebird (Sialia currucoides) male, Yellowstone National Park, Wyoming, United States of America, North America

Male mountain bluebird (Sialia currucoides), Douglas County, Colorado, United States of America, North America

Female Mountain Bluebird (Sialia currucoides) at the nest, Yellowstone National Park, Wyoming, United States of America, North America

Male mountain bluebird (Sialia currucoides), Yellowstone National Park, Wyoming, United States of America, North America

Mountain bluebird (Sialia currucoides), male at nest cavity, Yellowstone National Park, Wyoming, United States of America, North America

Mountain bluebird (Sialia currucoides), female exiting nest cavity, Yellowstone National Park, Wyoming, United States of America, North America

Mountain bluebird (Sialia currucoides) male feeding female, near Castlewood Canyon State Park, Colorado, United States of America, North America

Mountain Bluebird (Sialia currucoides), male with prey, Rocky Mountain National Park, Colorado, USA

Mountain Bluebird (male - sialia currucoides) on fence near Drumheller Alberta,