"Answer"
Immature/female hummingbirds are among
the most difficult field identification problems. Many responders
had difficulty with the reddish cast along the visible flank
of this bird. The identification problem becomes (slighly) easier
once you realize this is a reflection from the just-visible feeder
in the lower left-hand corner of the scan.
The bird has a relatively long, all dark bill that's very slightly decurved. The head is smudged gray with a noticeable white supercilium that extends from the top of the eye downward through the auricular area. The chin is almost all white with perhaps only the slightest hint of a stipple on the the throat. There appears to be a white line where the mandible meets the head. the back is metallic green with the slightest hint of bronze in it. The tail feathers appear mostly dark, with a very small amount of white at the tip. the belly is mostly white with a vest whose color is obscured by the reflection from the feeder. I'm not sure what to make of the coloration of the wing, to be perfectly honest.
This is not much to go on, but let's see how far we can get. The bird is pretty clearly not an tropical exotic from the rather dull plumage (i.e. anything on page 266 of NGS). It's also clearly an immature or female due to the lack of the gorget. We can rule out most selasphorous hummingbirds by the absence of the rufous anywhere on the bird. Immature BROAD-TAILED HUMMINGBIRD might be a possibility, but the tail doesn't look long enough, there is no rufous on the tail feathers and the throat doesn't look like it's stippled dusky.
Much more likely we're left with something either in the genus calypte or archilocus. Immature/female ANNA'S HUMMINGBIRD female/immature usually shows a pronounced stipple on the throat and lacks a white eye line/supercilium as well as being more dusky on the belly. However, some ANHU can approach being this pale as well as differing from adult females in other "confusing ways" (Kaufmann) and I wouldn't expect either the eye line behind the eye or the dark auricular patch on an ANHU.
I don't have much field experice with female/immature COSTA'S HUMMINGBIRDS, but Kaufmann indicates that COHU "often looks round-bodied or pot-bellied", which isn't apparent from the scan. Again from Kaufmann, "the back oftens has a plae or grayish look, and the underparts are nearly white, paler than in similar species. The throat is virtually unmarked white in adult females. A dusky patch on the ear coverts is well-defined (though not large), set off by the whitish throat and a pale line behind the eye." With the exception of overall gizz, this seems pretty good for this bird.
Kaufmann indicates that female/immature RUBY-THROATED HUMMINGBIRDS are not separable from BLACK-CHINNED HUMMINGBIRDS. The fact pattern also appears good for BCHU, and from the preceding sentence, RTHU. Anyone with any additionaly information on this would be most welcome.
So where are we? Basically, I don't think the bird is identifiable from the scan. However, having take the picture, I'm almost certain that the bird is, in fact, a female/immature BLACK-CHINNED HUMMINGBIRD, mostly because the bird was photographed in Southeastern Arizona in August. RTHU can be eliminated due to range and I did not see a single COHU while I was down there. BCHU, on the other hand, were a dime a dozen.
Do you agree? Send me email.
Last updated 13 May, 2000