Anna’s Hummingbird
(Calypte anna)
Anna’s, a medium-sized (9-10cm; 3-6g) species of hummingbirds, are commonly found in urban and open wooded or shrubby areas along the Pacific coast from British Columbia to Arizona. Conspicuous sexual dimorphism is exhibited in Anna’s hummingbirds. Adult males are slightly larger than the females and have a unique iridescent rose-red crown and gorget. Adult females and juveniles of both sexes display more cryptic colouration with a green crown and gray throat. During the breeding season (usually December-January) males perform a display dive by going up about 40m & diving over the recipient (usually a female hummingbird, sometimes people), flashing their gorget. They are very territorial. Anna’s also sing during courtship, unlike most species of hummingbirds. Anna’s hummingbirds have long, slender, straight bills. These birds feed on flower nectar using their long extendible tongue and catch insects in flight. They are important pollinators, especially of deep-throated flowers. Hummingbirds also have very high metabolic rates so when food is scarce and night temperatures are cold they enter a state of torpor. In torpor metabolic rates & body temperature decrease, substantially lowering the amount of energy used. Anna’s hummingbirds have greatly increased their breeding range in the past 60 years due to the planting of exotic flowering trees. Before the 2nd half of the 20th century, Anna’s bred only in California. Their numbers are steadily increasing.
References
birds.cornell.edu/AllAboutBirds/BirdGuide/Annas_Hummingbird
wikipedia.org/wiki/Anna's_Hummingbird