Mystery Bird: White-tailed Hawk, Buteo albicaudatus

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[Mystery bird] White-tailed Hawk, Buteo albicaudatus, photographed at the Attwater Prairie Chicken National Wildlife Refuge, Texas. [I will identify this bird for you in 48 hours]

Image: Joseph Kennedy, 22 November 2009 [larger view].

Nikon D200, Kowa 883 telescope with TSN-PZ camera eyepiece 1/750s f/8.0 at 1000.0mm iso400.

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

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This bird is a lot harder than it looks. It does seem a bit late in the season for this species, though. Most are already well south of Texas.

OK, I'll hazard a guess.

Raptor with long wings and a white rump. Northern Harrier?

A very cool photo, but surely this is an immature White-tailed Hawk, Buteo albicaudatus?

More brown than the grey-brown of adults above, white below (not that obvious here) with a white rump, a short tail still brown with several dark bars with the hint of a dark band at the end, yellow feet with black talons

And seeing that although the Juan Fernández Islands have been in the news lately, so the range of the polymorphic Variable Hawk (Buteo polyosoma) excludes it, are there any other buteos that have the same combination of chatacteristics visible above?

I'm calling this Buteo albicaudatus hypospodius whose range extends into coastal Texas and the Rio Grande valley.

White-tailed Hawk, Texas

Hadn't thought of White-tailed. I was thinking of juvenile Swainson's Hawk, which does show a pale rump and dark barred tail, just as this bird does. The lack of pale feather edging on the back combined with a pale rump may rule it out -- light morphs should show pale edging, dark morphs less white on the rump. I'm not sure that the tail isn't too dark for White-tailed, but they would be more likely by that date.

I'm afraid I had the wrong copy of Wheeler's up here - the Eastern one doesn't include Texas, and White-tailed just didn't hit me.

pk1154: Harrier was my first guess too. Aside from the short tail, which could conceivably be a foreshortening issue, the tail on a Harrier always shows 4 to 5 dark bands, not the multiple thin bands on this bird. Also, the wings appear very uniform, which suggests a bird in it's first year of life, but a juvenile Northern Harrier shouldn't show any banding on the primaries.

Hey Paul, thanks for the info at #4

I like your comparison of the two Swainson's morphs which did encourage me to continue to exclude Swainson's and stick with a White-tailed: initially I discounted the light morph Swainson's because of the lack of pale feather edging; when one enlargens the photo, I am sure that the thigh feathers are showing light/white and so although the dark morph Swainson's was a close match up top, the light below excluded it too (this seems to be supported by the two photos attached below)... simply based upon my first impression of this bird's relative size and shape, especially wing to tail ratio (I agree foreshortening can be an issue but I don't get that impression here) I didn't consider Harriers at all, but I could very well be wrong here, although I also sense a "heavier" bird than any Accipiter...

light morph Swainson's

dark morph Swainson's