Anna's Hummingbird (Calypte anna): The Complete Guide

Male Appearance

The adult male Anna's Hummingbird is among the most visually arresting birds in North America. His back and flanks are a rich metallic green, and his underparts are dingy greenish-gray --- adequate but unremarkable plumage that serves merely as backdrop for the real spectacle: a full hood of rose-pink to magenta iridescent feathers covering both the gorget (throat) and the crown. No other regularly occurring hummingbird in the United States displays iridescent color on the crown. In dim or angled light, this entire head can appear a flat dark gray or even black; tip the bird slightly toward a light source and it erupts into a blaze of saturated magenta. The tail is dark with a slight fork. He is noticeably stockier and heavier-looking than Black-Chinned or Rufous Hummingbirds, and unlike the fidgety tail-pumping of the Black-Chinned, Anna's tend to hold their tails relatively still while hovering.

Female Appearance

The female Anna's Hummingbird is green above and dingy grayish-white below --- typical of many female western hummingbirds. The most useful distinguishing feature is a small patch of rose-red or magenta feathers on the center of her throat, usually a few discrete iridescent spots rather than a full gorget. This throat patch is variable; some females show quite prominent color, others show very little. The overall impression is of a robust, stocky hummingbird with a relatively straight bill, plain face, and greenish wash on the flanks. Her tail is rounded, with green central feathers and outer feathers that are dull gray-green tipped with white.

Juvenile Appearance

Juvenile Anna's resemble adult females: green above, grayish below. Young males begin developing iridescent feathers on the crown and gorget by late summer or fall, and most have a recognizable (if incomplete) rose hood by their first breeding season. Juvenile females can be extremely difficult to distinguish from adult females in the field. Birds in their first year often show fine dark streaking on the underparts and a slightly fresher, less-worn look to their flight feathers.

Similar Species & How to Tell Them Apart

• Black-Chinned Hummingbird (Archilochus alexandri): Male lacks any color on the crown; his gorget is black with a narrow purple-violet lower band. Noticeably slimmer and longer-billed than Anna's; pumps and fans its tail vigorously while hovering (Anna's keeps tail relatively still).

• Costa's Hummingbird (Calypte costae): A desert-adapted relative with which Anna's occasionally overlaps. Male Costa's has a longer, more flaring gorget with purple (not rose) plumage, and the crown color is more purple-blue. Smaller overall than Anna's.

• Rufous Hummingbird (Selasphorus rufus): Male is unmistakably orange-rufous. Female shows extensive rufous on the tail base and flanks, absent in female Anna's.

• Allen's Hummingbird (Selasphorus sasin): Very similar to Rufous; females of both species show rufous flanks and tail contrast that female Anna's lacks.

Anna's Hummingbird is the only regularly occurring hummingbird species in the continental United States that does not undertake regular long-distance migration. Most individuals are year-round residents within their territories, remaining at the same location across all seasons. This sedentary lifestyle is one of the most distinctive ecological features of the species.

However, "non-migratory" does not mean "stationary." Post-breeding dispersal takes some individuals to higher mountain elevations in late summer and fall, following blooming sequences upslope. A subset of Pacific Northwest birds --- particularly first-year individuals --- may move southward in winter, and there is increasing evidence (as of 2017 research) that a sizable percentage of Pacific Northwest Anna's make seasonal movements. These are altitudinal or short-distance shifts rather than the true long-distance migrations of species like the Rufous or Ruby-Throated.

The expansion of Anna's range northward is an ongoing story. The species first colonized Oregon and Washington in the 1960s--70s, largely as a result of suburban landscaping and year-round feeders. It has continued pushing northward into British Columbia in the 21st century. This expansion is ecologically significant: Anna's now competes with migrating Rufous Hummingbirds for resources at feeders and flowering plants, and its year-round presence may be changing the competitive dynamics of western hummingbird communities.

Because Anna's are year-round residents rather than seasonal migrants, feeder management takes on added importance --- and some added challenges:

Winter cold: In freezing temperatures, nectar can ice up overnight, leaving birds without a critical energy source during the coldest hours. Use insulated feeder covers or bring feeders inside on cold nights and return them early in the morning. Rotating between two feeders --- one warming indoors while one is outside --- is a practical solution. Never use antifreeze additives.

Feeder style: Saucer-style feeders with shallow reservoirs are easier to keep clean and allow good visibility of the birds. Bottle-style feeders work well but require more diligent cleaning in warm weather. Anna's readily use both.

Placement height: 4--6 feet above ground is standard. Position feeders near perching branches --- Anna's males spend considerable time singing from exposed perches between feeding bouts, and proximity to a favored singing branch increases activity at the feeder.

Port size and bee guards: Standard port openings are appropriate. Bee guards are useful, as Anna's territories attract bees and wasps to the same nectar sources.

Nectar freshness: Replace nectar every 3--5 days in cool weather; every 2--3 days when temperatures exceed 75°F (24°C). In hot, direct sun, fermentation can begin within 24 hours --- shade placement extends freshness significantly. Clean feeders thoroughly with hot water and a brush before each refill.

Anna's Hummingbird has one of the earliest nesting seasons of any North American bird, with some California females beginning nest construction in November or December --- in the middle of what most people regard as deep winter. In the core California range, eggs can be found as early as January; in the Pacific Northwest, nesting typically begins in February or March.

The nest is a compact cup of plant fibers, thistle down, and feather down, bound together and to the branch with spider silk and decorated on the exterior with lichen flakes for camouflage. It is typically placed 3--30 feet above ground on a horizontal or angled branch, often in a sheltered microsite below the main canopy. The female builds the nest alone over 5--7 days.

• Clutch size: 2 eggs

• Incubation period: 14--19 days, by the female alone

• Nestling period: 18--23 days

• Broods per season: 2--3 possible in the long California breeding season

One of the most remarkable aspects of Anna's nesting is the timing: females incubate eggs and brood nestlings through cold winter nights in the Pacific Northwest and California mountains, a feat that requires careful thermal regulation. The nest's insulating cup design and the female's own body heat maintain egg temperatures while ambient temperatures may drop near freezing.

Males play no role in incubation, brooding, or nestling care.

Anna's Hummingbird is classified as Least Concern by the IUCN, with an estimated population of approximately 9.6 million individuals (Audubon Society data). The species is one of the few North American hummingbirds showing a clearly positive long-term population trend, driven in large part by range expansion into suburban and urban landscapes.

Conservation considerations:

• Positive: Range expansion northward and eastward is ongoing; urban and suburban gardens are providing genuine habitat gains

• Pesticide exposure: Year-round residency in suburban areas means chronic, year-round exposure to lawn and garden chemicals; avoiding insecticides and herbicides is particularly important for resident Anna's

• Window collisions: Year-round territorial behavior near buildings increases collision risk relative to migratory species

• Competition with Rufous Hummingbirds: Year-round Anna's feeders may be altering competitive dynamics with the Near Threatened Rufous at some Pacific Coast sites

What you can do:

• Maintain feeders year-round in Anna's territory, paying particular attention to feeder function during cold snaps

• Plant native Pacific Coast species that provide winter-blooming nectar

• Eliminate pesticide use --- Anna's rely heavily on insects year-round

• Apply window collision deterrents, especially on large south- or west-facing glass