The calliope hummingbird (Selasphorus calliope) is a very small hummingbird native to the United States and Canada and, during winter, Central America. It was previously considered the only member of the genus Stellula, however recent evidence suggests placement in the genus Selasphorus. This bird was named after the Greek muse Calliope. The genus name means “little star”.
This is the smallest breeding bird found in Canada and the United States. The only smaller species ever found in the U.S. is the bumblebee hummingbird, an accidental vagrant from Mexico. An adult calliope hummingbird can measure 7–10 cm (2.8–3.9 in) in length, span 11 cm (4.3 in) across the wings and weigh 2 to 3 g (0.071 to 0.106 oz). These birds have glossy green on the back and crown with white underparts. Their bill and tail are relatively short. The adult male has wine-red streaks on the throat, green flanks and a dark tail. Females and immatures have a pinkish wash on the flanks, dark streaks on the throat and a dark tail with white tips. The only similar birds are the rufous hummingbird and the Allen’s hummingbird, but these birds are larger with more distinct and contrasting rufous markings on tail and flanks, and longer central tail feathers.
The breeding habitat of calliope hummingbird is varied open shrubby habitats. Nesting usually occurs at higher altitudes in the Rocky Mountains. Nest have been observed from as low as 300 m (980 ft) in Washington elevation to thetree line at over 3,000 m (9,800 ft). In Montana, the minimum elevation they have been found breeding at is 1,200 m (3,900 ft). Open montane forest, mountain meadows, and willow and alder thickets may variously serve as breeding grounds. During migration and winter they also occur in chaparral, lowland brushy areas, deserts and semi-desert regions. They nest in western North America from southern British Columbia and Alberta south to Coloradoand southern California. During spring and summer, they move, mainly through Arizona and New Mexico and northern Mexico, to winter in southwestern Mexico as well as in Guatemala and Belize. Calliopes have been identified in Fort Tryon Park, New York and one was identified and banded in Lighthouse Point Park in New Haven, Connecticut in December 2006.
Calliope hummingbird is migratory bird, generally leaving their breeding grounds earlier than most birds (although not as early as the rufous hummingbird) to take advantage of the late-summer wildflowers in the mountains of western North America. They are believed to be the smallest-bodied long distance migrant in the world.
These birds feed on nectar from flowers using a long extendable tongue, drink sap from holes created by sapsuckers or catch insects on the wing. While collecting nectar, they also assist in plant pollination. Plants preferred for pollinating include paintbrush, penstemon, columbine, trumpet gilia, and elephant head. They will also occasionally catch and eat small insects and spiders.