The Calliope Hummingbird, Stellula calliope, is a very small hummingbird and the smallest bird found in Canada and the United States. It is the only member of the Stellula genus.

These birds have glossy green on the back and crown with white under parts. 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.

Their breeding habitat is open shrubby areas, usually at higher altitudes, in western North America from southern British Columbia and Alberta south to Colorado and southern California. The female builds an open cup nest in a conifer under an overhanging branch.

They are migratory, 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. Most winter in southwestern Mexico.

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. 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.

This bird was named after the Greek muse Calliope. The genus name means "little star".

Physical Description
Average weight: male 2.5 g, female 2.83 g. Female birds are larger than males.

Plumage
Adult male: Metallic green back and crown, white gorget with purple rays that may be erected to show a "whiskered" effect.
Adult female: Green back and crown, white throat with dark streaks, buff sides, white-tipped tail corners.

Distribution
Observed in Alabama, Arizona, Arkansas, California, Colorado, Connecticut, Florida, Idaho, Kansas, Louisiana, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Mexico, North Carolina, Oregon, Tennessee, Texas, Utah, Washington, Wyoming, Alberta, British Columbia, and Saskatchewan. Winters in west-central Mexico.