Mystery Bird: Rufous Hummingbird, Selasphorous rufus

Rufous Hummingbird, female.

Field mark: ruddy tail with black and white tip.

Nice one Emily...

Rufous Hummingbird (Selasphorus rufus):

long, straight and very slender bill; female has green upperparts, white underparts, rufous-washed flanks, bronze-green speckles on the throat, dark tail with rufous at the bases of the retrices, and white tips on the outer three retrices ...

No one has said why it is not an Allen's Hummingbird although Rufous is much more likely. It is partially concealed, but it looks like the outermost retrice is narrower than the other retrices(consistent with Allen's), but there is a "notch" in the first retrice without white (4th feather starting from the outside edge)which supposedly supports Rufous. Allen's have shown up in Texas on a number of occasions. Overall the retrices seem relatively broad - like a Rufous. Do we need measurements?

Jim, my impression was that the Rufous female exhibits more emerald on the back and more bronze on the crown...

and have you noticed a very slight downwards curve (I mean very slight) in the bill of Allen's as compared to Rufous?

although these are the Texas Bird Records Committee guidelines on the identification of Allen's:

TBRCs stance on Allen's Hummingbird

Jim pointed out the slightly notched or "pinched" tip of R2 (R1 being the central tail feather, R5 the outer), which is essentially diagnostic for Rufous (with extremely rare exceptions for hybrids). Not all "female-plumaged" Rufous will show it, however, so its absence is not diagnostic for Allen's.

Identification that will hold up to bird records committee scrutiny requires measuring the width of R5 on a bird in hand, but photos showing sufficient tail detail often allow identification based on the shape of of R2 and the proportion of width to length of the other tail feathers, especially R5 (not the width of R5 compared to the other tail feathers). Though R5 is partly obscured in this photo, the widths of the more visible tail feathers appear consistent with Rufous (= too wide for Allen's).

It's a minor point, but the apparent lack of a green band separating the black tip of R2 from the rufous base combined with the extensively rufous R1 and upper tail coverts indicate a juvenile male rather than a female (though tail feather shapes and amount of white would be similar in an adult female).

David, your description suggests the sedentarius subspecies of Allen's, which has a distinctly longer bill than either the migratory subspecies or Rufous (whose bill length falls between the two subspecies of Allen's).

Sheri, your comments are very useful- thank you!

So it appears that I must have been alternating between looking at photos of sasin and sedentarius...

I did consider an immature Rufous for a moment but erred on the side of female because of the pattern of blotches on the throat, and although the front is not visible in this photo, the neck area seems consistent only with females (Allen's and Rufous)...

as I have mentioned a few times before (Sunbirds, Asian kingfishers, etc,), at some point we're going to end up with a taxonomy within birds that moves further away from the traditional BSC concept of "species" [Ernst Mayr] towards one that encompasses phylogeny and also an ecological species concept defining a species as a set of organisms exploiting a single niche or adaptive zone (this would contribute towards the separation of the two Allen's subspecies as perhaps distinctly separate species)

David, I agree that the gorget markings are unusually small for a young male, but there's a very wide range of variation in this characteristic. I've banded juvenile males with gorgets more delicately marked than this and juvenile females with "five-o'clock shadow" worthy of Richard Nixon. There's a chance that the angle of R2 might be obscuring some green iridescence, but the relatively intact white tips on R3-5 and the faint rusty wash to the head tend to support an ID of juvenile male. (BTW, the classic paper on Rufous/Allen's identification is Stiles 1972, available online through SORA.)

Good points about taxonomy. Will we eventually have two lists, one for ornithologists of all identified species and one for birders of all identifiable species?