Monday, December 28, 2009

In the backyard... Anna's Hummingbird

Anna's HummingbirdAnna's Hummingbird, San Diego County, California, on 31 October 2008 by Greg Gillson.


Many backyard birders are beginning to discover that Anna's Hummingbirds are year-round residents west of the Cascades in the Pacific Northwest.

This resident hummingbird was formerly confined to California and northen Baja California. The first Oregon record was in 1944. By the 1960's it was established as a regular breeder, primarily in SW Oregon. The range expansion really took off in the 1980's and birds are now regular (and still increasing) north to southern British Columbia and, rarely, SE Alaska. It has also expanded into Arizona, where it is now common in larger towns.

The causes of the expansion of this hummingbird has not been studied, but is thought to be due to plantings of flowering shrubs. Anna's Hummingbirds are most common in the Pacific NW in larger towns with more winter-flowering landscaping. They have been less common in smaller rural communities, though they are increasing rapidly now into these areas as well.

Male Anna's "sing" all year long, but especially from December to April, the breeding season. The song is a long series of insect-like buzzes and clicks (like a miniature starling!). Nests are built and eggs laid as early as January, though some birds nest as late as April. The nest is the size of a walnut shell half, covered in spider silk and lichens. The eggs are the size of coffee beans and the tiny chicks are hatched naked.

Anna's Hummingbirds are quite large compared to the only common hummingbirds within its range in the Pacific NW. Anna's are all green on the upperparts, including the base of the tail, which is rusty on Rufous and Allen's hummingbirds. Additionally, the sides are green or gray on Anna's, but pink or cinnamon on Rufous and Allen's.

Anna's barely crosses east of the Cascades and is huge compared to the tiny Calliope Hummingbird. In comparison to Black-chinned Hummingbird, the male Anna's has it's whole head and throat amethyst-pink, while the male Black-chinned is mostly (you guessed it) black chinned. The crown of female Black-chinned is gray, while the crown of Anna's is green.

For information on feeding hummingbirds, see a previous article, telling how to make hummingbird nectar.