Broad-Tail Hummingbird

“The metallic wing-trill of the male Broad-tailed Hummingbird is a characteristic sound of summer in the mountain west. This sound is often heard as a flying bird zings past unseen. The birds are seen easily enough, however, at masses of flowers in the high meadows, where they hover and dart around the blossoms, often fighting and chasing each other away from choice patches.”

Audubon Society Overview: https://www.audubon.org/field-guide/bird/broad-tailed-hummingbird