Mystery Bird: Anna's Hummingbird, Calypte anna

tags: Anna's Hummingbird, Calypte anna, birds, mystery bird, bird ID quiz

Please name at least one field mark that supports your identification.

Rick Wright, Managing Director of WINGS Birding Tours Worldwide, writes:

We're usually so distracted by the bright colors of a hummingbird's head that we forget to start at the rear. In this case, though, our quiz bird is not a dazzling adult male, so there's little to divert our attention from the tail, which seems longish in comparison to where I imagine the folded wingtip would fall.

Equally important in this stunning photo is the structure of the wing. Note that all the primary feathers are of essentially the same width.

And what about the general shape of the bird? To my eye, this is a decidedly robust and tubular creature, shaped a bit like a toilet paper roll with a bill. The head is large and square, and the bill is straight, stout, and neither particularly short nor particularly long.

In plumage the bird is decidedly plain. There's no marked face pattern part from a smudgy postocular spot, and the underparts are dingy gray, perhaps with a hint of scaling.

Are you thinking what I'm thinking? There are only about 18 possibilities in Arizona, and the one that fits best is Anna's Hummingbird.

The apparently long tail, dingy underparts, stout body, and large head are not consistent with Costa's Hummingbird. The uniform width of the primaries is not consistent with Black-chinned or the accidental Ruby-throated. The absence of reddish brown on the flanks and rump should rule out Calliope and the hummingbirds. Magnificent, Blue-throated, Broad-billed, Violet-crowned, Berylline, Cinnamon, Lucifer, and Bumblebee Hummingbirds and Plain-capped Starthroat are all easily ruled out on gross characters of plumage.

So it's an Anna's Hummingbird--but of what age and sex? Notoriously, Anna's Hummingbird adults molt in summer; this bird has a complete wing of what look like fresh remiges. The upperparts have the fine golden scalloping so typical of young hummingbirds. And the bill is perhaps a bit on the short side, as if it hadn't reached its full adult length yet (I can't see any ridges in the photo, but bet they're there!).

Sexing this bird is trickier -- I'm sure someone out there more knowledgable will help. A dark "star" or scattered colored gorget feathers is common in adult female Anna's Hummingbirds, but I'd guess that only a male would show dark feathers on the throat at this early age.

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