A stocky, medium-sized hummingbird, the Anna's has a straight, short bill and a large tail that reaches past the wings.
Anna's is the only North American hummingbird with a full red crown and striking metallic greens over a gray belly. Anna's hummingbird males have iridescent pinkish rose-red crowns and throats.
If the bird looks more violet than rose, Anna's and Costa's hummingbirds may have mated.
Unusually, female hummingbirds have a tiny gorget formed by a red throat patch. Their backs are duller, iridescent green, with gray underparts and white eye markings.
Anna's usual body temperature is 107 degrees Fahrenheit, which may feel warm to humans. Torpor, a profound sleep, can decrease it to 48 degrees in cold conditions. About 20 minutes to “awaken.”
Heart rate: Anna's heart beats 600 times per minute, compared to the typical 60–100!
Like other hummingbirds, Anna's have tiny feet and legs and take no steps. They move by flying and landing.