The Calliope Hummingbird is the smallest breeding bird species in North America, measuring a mere 3 to nearly 4 inches in length.

The Calliope Hummingbird is the smallest bird in the United States. It weighs about one-third as much as the smallest North American warblers and about the same as a ping pong ball.

The calliope hummingbird (/ kəˈlaɪ.əpi / kə-LY-ə-pee; Selasphorus calliope) is the smallest bird native to the United States and Canada. It has a western breeding range mainly from California to British Columbia, and migrates to the Southwestern United States, Mexico, and Central America for its wintering grounds.