Subject: Re: Identity of Starling-devouring-raptor
Date: Dec 30 12:38:23 1997
From: Michael Price - mprice at mindlink.bc.ca


Dianne,

>In truth, I find it EXTREMELY difficult to tell different hawks apart,
>especially when they go off into different phases.
>
>Can anyone out there in Tweeter land give a quick guide on how to
>differentiate a Cooper's from a Sharp Shin (without analyzing their
>shins!)

Probably not in the described circumstances, Dianne. Sharp-shinned Hawk
(SSHA) and Cooper's Hawk (COHA) are notoriously difficult to distinguish in
at-a-glance flyby's, and under most similar circumstances, I'd encourage you
to be satisfied with an 'accipiter sp.' sighting.

There's the small-male/large-female thing. Measurements show none of the
accipiter species overlap but in the field, they seem to. Snap judgements
have two sides: proponents say first impressions are usually correct;
others, more cautious, wait for a mark to suggest identity. Either style is
okay as long as one's willing to not write anything in stone until a
diagnostic mark shows up. That said, even in flash-by sightings COHA of
either sex sometimes suggests slim build, SSHA stockier.

Jane's comment re looking at the tail is possibly the best suggestion in the
case of flash-by sightings, but could use a little amplification. The
square-vs.-rounded tail stuff is of little to no use in a quick sighting,
and is so dependent on too many things to be a consistent good mark--it's
certainly not one to use in isolation. One quick-sight mark you *might* be
able to use is that the COHA's tail is not only perceptibly longer than SSHA
but usually perceptibly narrower at the base than at the tip, whereas SSHA's
tail is the same width throughout and seems sorta short for the size of the
bird.

I'd suggest too that if you do get more than a here-she-come-there-she-go
sighting, a COHA is sometimes ID'able, sometimes even obvious; the ID
problem is more often offered by SSHA.

Echo Cliff and Rick R's reference suggestions: they're all useful and
field-portable.

Michael Price A brave world, Sir,
Vancouver BC Canada full of religion, knavery and change;
mprice at mindlink.net we shall shortly see better days.
Aphra Behn (1640-1689)