[birdky] INFO: Solution to last month's raptor quiz bird

The immature raptor posted as a Quiz Bird on the KOS web site last month
at the following link:
 
http://www.biology.eku.edu/kos/what_is_it.htm
 
is a juvenile Red-shouldered Hawk. 
 
This bird threw some of us off because it does not appear to be as
boldly streaked on the upper breast, nor have as buffy a ground color to
the feathers of the underparts. However, it does show several characters
that are not inconsistent with Red-shouldered and one that is very good
but hard to see/detect.
 
One thing that is clear ... this is a young hawk. It has a pale
(seemingly pale yellowish-gray) iris (most adult hawks in our area have
darker irides). It is heavily streaked below with clean, pale edgings to
the feathers of the upperparts, all indicative of a juvenile (i.e.
hatched earlier in the summer of 2008).
 
The bird in all respects appears to be a Buteo rather than a falcon or
member of the genus Accipiter due to the following characters:
relatively bulky body, rather thick tarsi (legs), large feet, and short
tail (relative to the length of the primaries).
 
The bird was photographed in Louisville in August, so potential expected
candidates are Red-tailed, Red-shouldered, and Broad-winged hawks.
 
Red-tailed can be eliminated by the presence of streaking on the upper
breast. 
 
Broad-winged can be eliminated by the presence of patterned (barred)
secondary feathers (obvious pattern of alternating medium gray-brown and
dusky bars). These feathers are placed on a perched bird (and in this
photo) as the block of feathers just above the undertail coverts (see
Sibley pp. 117 & 118 for comparison). This bird also doesn't seem to
have quite the right pattern of streaking/barring on the underparts,
including the face, for Broad-winged.
 
The presence of the streaking on the throat area and the barred
secondary feathers is consistent with Red-shouldreed Hawk. We can't see
the pattern of tail banding very well, but what appears to be numerous
bands without a noticeably wide, dark sub-terminal band is also
consistent with Red-shouldered (as well as Red-tailed).
 
The *one* character that is definitive for Red-shouldered that can be
seen if you look closely, is the buffy color at the bases of the
primaries, visible as a few buff-colored (rather than whitish) edges on
at least a couple of the inner primaries. This color difference is
subtle in this photo because the primaries are so tightly aligned with
one another and because the bird is in shadow. However, it is present.
 
I'm not sure, but the length of the tarsi and size of the feet may also
be too great for Broad-winged? These characters are probably at least
suggestive of Red-shouldered/Red-tailed rather than Broad-winged.
 
If anyone has anything to add, please do so; I'm not the best on these
guys and could have messed something up in my discussion.
 
Thanks to Terry Schwartz for submitting this photo for use in our quiz.
 
bpb

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