JACKSON, Wyo. — The birds are back!
Mountain bluebirds (Sialia currucoides) are among the first nesting songbirds to return to the Greater Yellowstone Ecosystem each spring, typically around mid-March. Their song marks the spring equinox and a welcome change after a long winter.
According to the Jackson Hole Wildlife Foundation (JHWF), this species of bluebird is believed to be on the decline in the West due to habitat loss and competition for limited cavity nests from invasive species like house sparrows and European starlings. Bluebirds nest in small cavities in trees, small cliffs and artificial nesting boxes. They often return to the same nests, accumulating the same nesting materials year after year.
These songbirds lay their eggs any time between late April and early June. They often socially mate for life, and will migrate back to their summer range early in the spring in order to secure a nest.
According to the U.S. Forest Service’s Mountain Bluebird Technical Conservation Assessment, male mountain bluebirds arrive to their breeding grounds about one week prior to females. Males quickly establish territories around potential nest sites and are then visited by prospecting females. Once a pair-bond has formed, males spend a large proportion of their time mate-guarding, in an attempt to ensure paternity. Both sexes will readily attack same-sex intruders but not intruders of the opposite sex.
Mountain bluebirds live in the western half of North America, and their annual migration covers thousands of miles, over several mountain ranges and, in some cases, several countries, according to the U.S. Fish and Wildlife Service. Some stay in Jackson Hole for the summer, while others continue farther north into Canada to nest.
After bluebirds nest in the spring, and the young have fledged, the birds form small hunting flocks later in the summer. The species can often be seen perching on the edge of open areas. From their perch, they watch for insects and spiders to eat. According to Jackson Hole Wildlife Safaris, one of the best places to see bluebirds is the open fields and grass land at Elk Ranch and Antelope Flats in Grand Teton National Park.
