Costa's Hummingbird (Calypte costae) is a small hummingbird. The male Costa's has a mainly green back and flanks, a small black tail and wings, and patches of white below their gorgeted throat and tail. Its most distinguishing feature is its vibrant purple cap and throat with the throat feathers flaring out and back behind its head. The female Costa's hummingbird is not as distinct as the male, having grayish-green above with a white underbelly.
The male Costa's hummingbird's courtship display is a spirited series of swoops and arcing dives, carefully utilizing a proper angle to the sun to show off his violet plumage to impress prospective mates. Each high-speed dive will also pass within inches of the female, perched on a nearby branch, which will be accented by a high-pitched shriek that is produced by the tail. Separately, the male will perch and produce similar sounds in his song—except, the song is vocal rather than tail-generated.
The female Costa's on the nest was photographed at the Hummingbird house at the Arizona Sonora Desert Museum.