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Hawk 2 - US, Seattle Washington (1 Viewer)

BodyResults

Well-known member
Hello All,

Here is another hawk spotted in the Seattle area on August 12th. I'm really not sure what type it is. It seemed a little smaller than a crow size but I was a good distance away and it was tough to judge.

Thanks for your help.
 

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Interesting bird. I'm gonna go with Cooper's based on the leg thickness. The apparent heavy streaking on the breast and upper flanks does suggest Sharp-shinned, but I think we need to go with structure over plumage here. Note also that the streaking is quite fine below the legs.

Best,
Jim
 
I'm leaning toward Cooper's, too, mostly due to what appears to me in Photoshop to be 5-6 graduated tail feathers on the one side that we can see. Sharpie's would be a single length.

But the breast streaking is a bit problematic, as Jim notes, and at this angle it's really hard to tell except for those that show below the leg, which are much finer than on the upper breast.

Two other things bother me, though, about this being a Cooper's. The left leg does indeed look "thicker" but it's also being shot from the side, whereas the right leg we're seeing from the back, and it is noticeably more delicate looking. Also, and this is admittedly a subjective observation, it just doesn't have that "fierce" look or the more hooded appearance to the head that a Cooper's at any age usually has (and this is obviously a sub-adult).

Body Results, don't suppose you have another photo of this bird from a slightly different angle?
 
I certainly do have more photos. Here are 4 more. These should help as they show several angles. I probably have about 30 of that bird.

Thanks for the help identifying this hawk.
Doug
 

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Okay, I'm with Snowcap in the Sharpie camp now. :t: That heavy breast streaking and the thin legs are obvious. The different lengths in the tail feathers appear to me to be a function of molting -- especially from picture #1 of your series of 4. Side and central feathers are different lengths coming in.

This is a really great series of images, too, Doug. Was this bird fairly recently fledged? It looks like it's "testing" its balance and flight capabilities as active as it seems to be on this one perch.
 
I'll go with Sharpie now also. The legs still look thick to me, and the white tail tip fairly broad, but Cooper's just don't show breast streaking that thick and that far down AFAIK. These photos are causing me to be more cautious in using leg thickness to separate these two. This one must be a big female.

BTW. Read recently that a study suggested there's a non-trivial proportion of accipiter mis-ID's at hawk watch sites, even when veteran watchers are involved. (http://www.wildlifejournals.org/perlserv/?request=get-abstract&doi=10.2193/2009-255&ct=1)

Best,
Jim
 
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I see JanJ has beat me to it - but I was going to mention that there are both heavily streaked as well as lightly streaked individuals, and the plumage overlap is nearly complete between the two species. I never try to separate on plumage - (or rather - I promise myself to never try) so I've been mostly just watching the past few Cooper/Sharpie threads.

But take into consideration the above, and remember that Pacific birds tend to be darker and smaller than their Eastern counterparts.

Here is an excerpt from Wheeler's western "Raptors" on the heavily streaked Cooper's juvenile: "Breast, belly and lower belly can be uniformly marked with dense brown streaking.....Markings are often heart or diamond shaped on the belly, lower belly and flanks. Flanks typically have a discernable dark brown bar on the inner portion of each feather....Undertail coverts may be unmarked white but are likely to have field-visible streaking, especially on the distal feathers."

Another field mark is the skin on the orbital ridge, which is yellow in Sharpies but gray on Coopers. Not very practical in the field, but with today's photography many times its easy to distinguish in photos if it is visible.

I highly recommend reading Wheeler's complete treatment of these two species.

My personal opinion is Cooper's on this bird; but its just an opinion.
 
JanJ, as usual, you send me back to the textbooks! LOL! Wheeler & Clark in this case. And after poring over both species accounts, and going over Doug's photos, I'm still camping with Sharpie. ;)

Except for relative size, the genders of both species are not sexually dimorphic. I can't tell from these photos the size of Doug's bird but am curious why you say this is a male...?

Undertail covert streaking on the juveniles of both species is thin. But the upper breast and belly in Coops have a consistently thinner streak, making them appear much more elongated than a Sharpie's streaking. Also, it makes a difference whether the bird is slightly fluffed (due to cold, e.g.) which can broaden the streaking's apparent thickness. But the shape of the individual feather's streaking is also different in each species. Cooper's again is very thin and has a more graduated roundness (almost teardrop shaped) where Sharpie's is wider and almost immediately bulbous as the streak descends. And in Cooper's, the streaking gradually narrows even more as it descends to the belly. In Sharpie, the more robust streaking stays robust almost 2/3 the way to the tail and then starts tapering off a bit.

I'm not sure the white terminal band is really diagnostic. Even in Wheeler & Clark, two different ventral shots of juvie Sharpies in flight show a wide AND a narrow terminal band.

Eye placement and head shape are difficult to see in Doug's photos due to angle. He says he has more tucked away -- maybe a good, flat side view would be helpful. :t:

Not that this gives any credence to my opinion, but in AZ where I lived for almost 5 years, we had Sharpies and Coops in the yard on a daily basis, a couple times even together (until the Sharpie spied the Coops and took off in a big hurry!). They nested on nearby properties and the birds that came to my bird feeders were the attractant to the juvenile and adult hawks. And even seeing them that much, I find photo IDing them still very, very difficult. In the field, not so much at all because you can look for and usually get the field marks.
 
I see JanJ has beat me to it - but I was going to mention that there are both heavily streaked as well as lightly streaked individuals, and the plumage overlap is nearly complete between the two species. I never try to separate on plumage - (or rather - I promise myself to never try) so I've been mostly just watching the past few Cooper/Sharpie threads.

That contradicts what Kenn Kaufmann says in Advanced Birding (1990). He says streaking like this is diagnostic for Sharpie (thick with barring and extending all the way down IIRC), but some Sharpies may have lighter streaking similar to Cooper's. But perhaps we've discovered he's wrong. Don't have time to try to sort this out at the moment.

Best,
Jim
 
The well marked streaking of the subject hawk does of course invite to it being a SSH, but as mentioned - western birds (males) can be quite well-marked - as shown by Garretts pic, and at the same time some SSH are finer marked as Jim mentioned. Regarding Kaufmann, the wide white tips to the tail condradicts juvenile SSH.
However, as shown by Kaufmann, the tips of juvenile SSH can give the impression of being broad. The explanation to this is a greyish base of the tip with more or less a contrasting white tip (http://www.pbase.com/image/9168128). I was looking for this feature in the subject hawk but failed to detect such a contrast. This, however, might not be visible due to the lightning in these (exellent) pic.
The iris is greenish tinged - usually yellower in SSH.
Again check Garretts pic.

This one is labelled Sharp-shinned...

http://www.pbase.com/khanh007/sharp_shinned_hawk

JanJ
 
Thanks for the thorough review and for the compliments on the pictures.

Here are 4 more pictures. Hopefully they give a little more insight. The 4th picture shows a couple smaller birds in the same tree. During a 10 minute period there were 10-12 birds that seem to irritate the hawk a couple times and caused the hawk to adjust positions in the tree to scare of the smaller birds.

Thanks
Doug
 

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Coop and Sharpie

A few years back there was a similar discussion on our local bird list from the UW. A local falcon expert, Bud Anderson, chimed in. He claimed that the best way to distinguish between them was by the shape of their head. A Sharpie has a forehead of sorts with the beak projecting out like the bill of a hat. A Coop's head and beak is more of a single arc.

We were fortunate to have both a male Coop and a female sharpie perch on a fence in our yard. We took pictures at the same magnification and were able to manipulate the photos to have the boards the same width. That puts the birds in prospective to the fence to compare size.

Our Audubon western birds states a Sharpie is from 11 to 14 inches. Coop 14 to 21. The size variation is due to the fact that females are normally larger in birds of prey for their safety. Our combined picture shows that a female sharpie and a male Coop are about the same size as their size suggests. The big difference would be in an 11 inch male Sharpie and a 21 inch female Coop. We hope to get them on the fence for that comparison.

We showed this picture to Bud. He agreed with our identifications and head shapes. The shape of the Coop head in profile is easy to recognize once you know what to look for.

BobnBernie

Link to picture

http://i30.photobucket.com/albums/c301/BobnBernie/CoopersandSharp-shinnedcopy.jpg
 
Sorry, BobnBernie, but the feathers are raised on the right bird in your photo comparison, thus giving that concave indent above the beak. If the Cooper's feathers were raised, you'd see the exact same thing -- but more importantly, and more diagnostically correct, you'd see the hackles raised on the nape which gives Cooper's its distinctive hooded look where a Sharpie's head always appears more rounded on the back.
 
A local falcon expert, Bud Anderson, chimed in. He claimed that the best way to distinguish between them was by the shape of their head. A Sharpie has a forehead of sorts with the beak projecting out like the bill of a hat. A Coop's head and beak is more of a single arc.


Thank you for posting that! I had also been told to use the vertical forehead as a field mark between the two - but had no source to attribute it to. I find it very helpful, although at some angles its not always easy to discern.

Your link illustrates this quite well. - and also illustrates why plumage is hard to use as a lone field mark.
 
We stand by what we have posted. Here is a link to a mature male Sharpie. He stayed long enough to take a lot of pictures. They all look like this.

http://i30.photobucket.com/albums/c301/BobnBernie/thesharp-shinned.jpg?t=1286743837

We came to this post after reading Body Results post on the UW forum. While we were posting here, Bud was posting on the UW forum stating it was a Coop and why. Here is part of that post;

This bird is definitely an immature male Cooper's Hawk hatched out this summer, perhaps locally.

So you know, I base this opinion on the following five features.

1.) In your first photo, you can clearly see the diagnostic head profile. Cooper's Hawk heads, especially in profile, are totally different than Sharpys. COHAs have a beautiful, smooth sloping profile (similar to a Golden Eagle), uninterrupted by the slight "forehead" above that cere that is so typical of SSHAs.

BnB
 
I'm going back to my original Cooper's Hawk call after additional review of my references and JanJ's links.

-- after rereading Kaufman, I think this bird does not match the pattern he calls diagnostic for Sharp-shinned Hawk because the streaking is plain brown rather than reddish-brown, and there are no crossbars. What he says is "the extreme pattern shown here for Sharp-shinned (with broad reddish-brown streaks and some crossbars with buffy white background) is diagnostic". (Advanced Birding, page 61).

-- Kaufman notes that the undertail coverts of Sharp-shinned Hawks are always pure white. Cooper's on the other hand can have thin streaks. We can see thin streaks on the UTCs of the subject bird.

-- thanks to Whooping Crone for pointing out the passage in Wheeler's Western Raptors. However, I see that at the bottom of that description is a note saying this plumage is "not depicted". That seems to me a major failing in his book. I thought the whole point of having a specialized photo raptor ID guide is that you have room to depict all the significant variations, so flipping through all the photos will show you the range of variation. This case shows that his collection is misleading in this regard.

Best,
Jim
 
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Here is an interesting link that gives actual measurements and weights of the 3 North American Accipiter Species as compared with the Peregrine Falcon. It also gives identification keys to both the Cooper's and the Sharp-shin.

As you can see the Cooper's hawk is considerably bigger than the Sharp-shinned hawk even when comparing a male of the former with a female of the latter. Interesting comment in it also at the bottom of the list about the relation of size and body weight between the Cooper's and the Peregrine.

http://www.peregrine-foundation.ca/raptors/Sharpshinned.html

Bob
 
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