[CT Birds] Accipiter ID - Answer
joseph.e.cala at gmail.com
Sun Jul 20 22:20:43 EDT 2014
Can I claim 'yes and no'? Ha!
I would *strongly* caution anyone from using a single accipiter field mark
as being 100% diagnostic -- at least in the field. Clearly size in the
hand is diagnostic, but plumage and/or structure field marks need to be
used with some caution.
The problem with structure field marks is that they're all subjective.
Several of the folks who have looked at this bird (here and ID forum) have
stated that the head isn't that big, that the wings are stocky, etc etc.
So relative head size on a flying bird can certainly be very subjective and
depends on what one considers 'large'.
Typically when you have an unknown accip with a head that appears large and
sticks out a ways past the wings--yes, it'll be a Coop. There are also the
weird Sharpies that have larger heads (females) that can fool you. When
attempting to ID these birds, juveniles especially, I'd advocate for a
multiple field mark approach.
Heck, even rounded tails and tail feather graduation CAN be diagnostic, if
the person making the ID remembers that female Sharpies frequently show
graduation to the tail and molt and wear can turn a square tail into a
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