Monday, June 15, 2009

Quiz #304 (2009-2-12) Answer

Click the picture for a larger view.

Answer by Tony Leukering

We have a dark, long-winged raptor going away from us. If the thing doesn't swoop up to a perch soon, we might not get any better look at it, so let's try to get an ID now. The most distinctive aspect of the bird are the large patches of white in the outer wings. Many buteos show pale panels like this, but there are a couple of other options with white wing patches, particularly Golden Eagle and Crested Caracara. The fact that there's no suggestion of white in the vent area should rule out the aberrant falcon mentioned above, as does the lack of white in the tail. Interestingly, that lack of white in the tail should also rule out the eagle, as any Golden Eagle with this much white in the wings would exhibit a fairly large amount of white at the base of the tail. That leaves us with the buteos.

Before working through the buteos, I'll first deal with wing panels. In this genus, wing panels are created by pale inner webs to the primaries and, in Red-tailed Hawk, paler primary coverts. Panels are typical of juveniles in the genus, but are features of adults in three species, Red-shouldered and Ferruginous hawks. The panels on Red-shoulderd are distinctive in being crescent-shaped and formed by a smaller number of primaries (with none of the innermost primaries involved), rather than most of them.

So, looking more closely at the wing panel, we should note that the pale does not extend into primary coverts (if it did, the patch would be a different shape -- trapezoidal) and that it is extensive, so we can rule out Red-tailed and Red-shouldered hawks and those species that typically lack wing panels. We are left with Gray, Broad-winged, Ferruginous, and Rough-legged hawks. Gray Hawk is never as dark as our quiz bird, which also cannot be an adult Broad-winged as it would show distinct white tail bands. Juvenile dark-morph Broad-wingeds can have a fairly dark-appearing tail (though banded like light-morph juvs), but we can eliminate the species in its entirety by the very long wings of our quiz bird.

Ferruginous Hawks are known for their whitish tails, so this must be a Rough-legged Hawk. If so, then it must be a juv (wing panel). However, even juv dark morphs of that species have at least a bit of whitish at the tail base, so what gives? Though light-morph Ferruginous Hawks do have pale tails (which can be quite white, but often red-suffused), dark morphs can have entirely gray or gray-brown tails, just like the one in the quiz photo. In fact, the quiz bird is a dark-morph Ferruginous Hawk, a beast that is, according to Aaron Brees, "possibly the single best bird north of Mexico." The photo was taken near Salina, KS, by Gregg Friesen in early January 2009. Thanks, Gregg!

It was interesting to see that most of the correct respondents live in Colorado, including (I think) all three of the related Such-Germain clan. The six correct Ferruginous Hawk responses barely beat out the five each for Rough-legged Hawk and Golden Eagle as the species most picked by respondents.

With one quiz to go, the quarter's leader board is topped by Aaron Brees (with 11 of 12 correct); Bryan Guarente (10 correct); and, tied for third, Mark Dettling and Marcel Such (each with 9 correct).

One incorrect response was also missing the all-important initial capital in 'hawk.'

Tallies of incorrect species provided in answers:
Crested Caracara - 1
Golden Eagle - 5
Rough-legged Hawk - 5
Turkey Vulture - 1
Northern Harrier - 1
Red-shouldered Hawk - 1

The 6 of 20 providing the correct answer:
Aaron Brees
Victor Germain
Marcel Such
Bryan Guarente
Joel Such
Chishun Kwong

Answer: Ferruginous Hawk