[CT Birds] Accipitor ID
Mntncougar at aol.com
Mntncougar at aol.com
Mon Jul 21 14:57:40 EDT 2014
Joe, I think, based on the 2 photos you supplied, it is unrealistic to
flatly state the bird is a Coop. It well may be, but there is nothing so
diagnostic in those photos as to rule out a Sharpie. There are too many things
that can't be told from these pictures to make a certain ID in my opinion,
which is why I didn't respond and perhaps why none of the other LHP
hawkwatch counters did either.
It does appear that the bird is still in a molt, or, given that it's a
juvenile, may be still growing out it's first full set of flight feathers.
However, the tail is quite long for either species, and I doubt that any
remaining growth is going to change the shape very much. At the same time, I can
agree, the head PROJECTION, which is the real ID key, does look long for
a Sharpie, although the head itself looks rather small in comparison to the
body. It is possible the angle the photos were taken from has some
influence on the appearance.
And in the 2nd photo the wings do look rather short for a Coop. I don't
think the wing shape in either photo can be considered diagnostic. It's true
that juvenile Sharpies often have darker and more extensive striping on
the breast and belly, but it is extremely variable, and to use it alone
would be a mistake.
One thing not mentioned at all in this discussion is the white on the tip
of the tail. Generally a Coop will have more than a Sharpie and more than
is shown in the photos. There are some other appearance issues as well.
But it's the things we cant see in those photos that are the most
important. Number one, how big is it? In the 2nd photo it looks fairly small, but
frankly that can't really be told from a photo. An experienced hawk watcher
will have a fairly good sense of size given that good of a look (almost
straight up) in the air. If it appears really small, chances greatly increase
that it's a sharpie. A small male is unmistakable.
Number 2, how does it fly? Both species use "flap flap glide", but one of
the better identifiers is how forceful the "flap" is. A Coop generally has
a fairly strong, powerful looking stroke, while a Sharpie usually looks
relatively weak and tentative. And notice the word "relatively." Beyond that,
both birds tend to bounce around a bit, but it is much more noticeable in a
Sharpie, particularly if there is a good breeze blowing.
Head projection is a much better indicator when the bird is seen flying
because you generally can see it from different angles. Sometimes the head
almost seems to disappear between the wings on a Sharpie.
Were there any other birds with it? Was there any chasing going on?
Sharpies tend to chase both each other and Coops more than Coops do, though both
will, on occasion. Sharpies are somewhat more likely to be in pairs or
groups than Coops are.
Another question, of a different sort; what is the relative abundance of
the 2 species in the area where it was seen? At Light House Point we have a
relatively high count of Coopers Hawks, but in most places on the east
coast the Sharpie percentage is far higher. On the other hand, If you see an
accipitor in southeastern Arizona, 99 to 1 (or more) it's a Coop. I've birded
there for years and only this year did I see a Sharpie. Took me a long
time to make my decision on it. This may seem an odd point, but I think it
applies the same as it would to a possible rarity sighting: always answer why
it isn't what you would expect to see first.
Again, I'm not disputing that it may be a Coop, but I think we have too
little information to be certain.
---- Joseph Cala via CTBirds <ctbirds at lists.ctbirding.org> wrote:
> One of the ID forums that I participate in had a very lengthy debate over
> the ID of this accipiter, and I figured that since this one species that
> many folks struggle with -- and given that we'll start seeing a lot more
> juveniles of these species in the coming months -- a picture quiz might
> This particular bird presents some very fun ID challenges -- I won't cite
> which ones specifically because that would potentially give away the ID.
> This bird was seen in Boise, Idaho recently. Here are the two pictures
> that were presented:
> I'd love to hear everyone's opinions on this ID -- and why, if you're
> interested in playing along. As an FYI I've had two very esteemed raptor
> ID experts (and authors) concur on the ID.
From: Joseph Cala <joseph.e.cala at gmail.com>
To: ctbirds at lists.ctbirding.org
Subject: [CT Birds] Accipiter ID quiz - Answer
<CAHXZuFTa-ymdRTZN3gS0G4hN0_mThjs8uRABKkamdmPXxDh9=Q at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Only received a few responses (and see a few more on the forum) but
hopefully more of you were able to take a look at the pictures and
formulate an ID.
I specifically picked this bird because it represents probably the most
mis-ID'd hawk there is out there. The whole accipiter complex can be
difficult (remember the recent backyard Goshawk reports/pics that all
turned out to be Cooper's Hawks) but the most challenging in that complex
by far is male Cooper's Hawks and female Sharp-shinned Hawks.
Most hawk watch folks or savvy birders can instantly recognize a female
Cooper's Hawk or male Sharp-shinned Hawk--the differences in flight and
size are pretty unmistakable. Things become infinitely more difficult when
it's the other way around -- as male Cooper's can be almost as small as
female Sharp-shinned with just a couple of inches in overlap--obvious in
the hand, not in the field.
In any event, the bird in question is in fact a male Cooper's Hawk. The
larger head, unstreaked throat, sparse thin breast streaks that fade
towards the tail all point towards that ID. I know the tail is a major
point of contention - it helps to note that the bird is currently in molt
which is making the tail appear much more Sharp-shinned like than the
normal graduated/rounded Cooper's tail.
The wings and profile of the bird in the 1st picture definitely appear
Sharp-shinned at first glance, but understand that the bird is in a 'wing
down-flap' and makes those wings appear much stockier than they are --
which you can see in the 2nd picture for comparison's sake. The 2nd photo
shows less stocky, and much longer wings.
Don Morgan, Coventry
mntncougar at aol.com
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