Subject: [Tweeters] Can you help ID this Hawk?
Date: Jan 8 15:27:39 2011
From: Kevin Purcell - kevinpurcell at pobox.com


On Jan 8, 2011, at 1:33 PM, notcalm at comcast.net wrote:

> Looks like a juvenile Northern Goshawk to me. There is a very clear white supercilium (eyebrow), which is a key field mark for this species. However a few of the field marks cannot be seen in this photo and it is difficult to see size perspective, which could rule out Cooper's Hawk. Does he have more photos of this bird?


Size and bulk would be a good guide. That tree branch (and the picket fence) make me think smaller (sharpie or coop). So is this jay-sized, crow-sized or red-tail-sized? Just on the 2x size, 8x weight difference (and so flap rate) between a Sharpie and a Goshawk you shouldn't confuse these by eye. If only we had a movie. eh, Dan :-)

Having blown the photo up I no longer certain the eye is yellow: orangey? red even (that would blow the juvi id). It's difficult with so few pixels and unknown white balance. The belly doesn't look orange more a dirty gray so a juvi id is still possible though an adult Goshawk would have a gray belly.

There is a good view of the tail, back, wing anmd undertail coverts in the photo. So look for other field marks.

Wide white supercillium is a mark on goshawks but also juvi sharpies and less so on juvi coops.

Goshawks have irregular tail banding (Sibley and Wheeler & Clark) where the tail feathers don't all align with each other. The black bands have adjacent narrow white bands (Sibley and Wheeler & Clark). I don't see either of these in the photo.

Juvi Goshawks have a "tawny bar on the upperwing coverts" (Wheeler & Clark). I don't see one.

Juvi Goshawks have a "heavily mottled back and upper wing coverts" (Wheeler & Clark) more than the spots you get on juvi coops and sharpies. I don't see any mottling just a couple of spots.

Undertail coverts are clean and white with no streaking. You'd expect a Goshawks to show a few more streaks (Sibley and Wheeler & Clark) though as Jack Bettesworth has pointed out this can be a variable feature in both Sharpies and Coops so I presume the same maybe in Goshawks?

The tail looks long and thin to me. The Goshawk has a broader tail "aspect ratio" than the Coop or Sharpie but that's a bit of a hand-waving argument.

The preponderance of evidence is against a Goshawk, I think.

I suspect it's a sharpie but wouldn't be too surprised if it was a coop given the photo.

Finally "A Photographic Guide to North American Raptors" by Wheeler & Clark p34 has a very nice photo (SS07) of a juvi Sharpie (with a big white supercillium) that resembles this photo. Compare with the juvi Goshawk on p41.
--
Kevin Purcell (Seattle, WA)
kevinpurcell at pobox.com
http://kevinpurcell.posterous.com
http://twitter.com/kevinpurcell

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