[SBB] Accipiter query -- summary of responses

["Tom Grey" <[[email protected]]>]

To refresh your recollection, I asked for ID discussion of the immature
Accipiter(s) shown in the four pictures at
http://www.pbase.com/tgrey/accipiter_query. I've since added a second
picture of the bird shown as "Accipiter 3" -- this one shows the head in
direct profile.

Accipiter 1 and 2 are of the same bird, photographed 11/23 in a single view
near Arastradero Lake. I took the Accipiter 3 (and 3a) photo a little less
than an hour after the other two, near the park entrance south of
Arastradero Road. The final photo, of a bird certainly a Cooper's, was
taken four days earlier (11/19) very near where Accipiter 3 was
photographed.

Responses varied fairly widely, but converged on a consensus that Accipter
1-2 is a Cooper's Hawk. The legs, visible in both shots, look too thick for
Sharp-shinned; the head shape looks Cooper-like (larger, and more blocky
rather than small and round.) .

Most thought Accipiter 3 was also a Cooper's; reasons given included shape
and relative size of head, and orange-buff coloration of the crown.

Mike Rogers argued that the pictures actually show three different birds --
1-2, 3, and Cooper's (4). Mike agreed that 1-2 and 4 were certainly
Cooper's, but thought 3 could not be called between male Cooper's and
female Sharpie, given head size/shape, and tail tip configuration. Here's
Mike:

"Bird 4 is almost certainly different, with much darker brown (less rufous)
streaking below, more extensive white in many places (including some median
coverts), a different primary extension (4 tips visible, with 2 rather than
1 projecting only a short ways beyond the secondaries/tertials).

"Likewise, bird 3 does not appear to be the same to me. It appears to be in
molt, with an apparent gap in the primaries and perhaps a dropped upper
tertial (I have not checked to see whether this molt timing is expected for
a juvenile of either species - it may not be - in which case, if feathers
are being replaced it is a result of accidental feather loss). The bird
does look smaller and has a less rounded tail, suggesting perhaps a small
COHA (male?) or big SSHA (female) - would be nice to see the legs on this
one."


Siobhan Ruck thought Accipiter 3 was a Cooper's, like the others, and gave
reasons:

" Even though the tail shape looks sorta square in the third
photo, the shape of the tail feathers is still distinctly rounded at the
ends (sharpie tail feathers are more squared off, as well as having a
squarer tail shape).  The shape of the head is the classic coop
blocky-wedge thing, vs. sharpie's rounder head.  The eye is more forward
and heavily browed than a sharpie, and the eye does not have a sharpie's
"mascara" look."




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