It has a bronze-green back, a light grey chest and belly, and green flanks. Its bill is long, straight and slender. The adult male has an iridescent crimson-red crown and throat, and a dark, slightly forked tail. Anna's is the only North American hummingbird species with a red crown. Females and young have a green crown, a grey throat with some red markings, a grey chest and belly, and a dark, rounded tail with white tips on the outer feathers.