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Sharp-Shinned vs.Cooper's: I.D. Question posted by Joshua Eastlake on December 9, 2009 at 09:37:57

Re: Sharp-Shinned vs.Cooper's: I.D. Question posted by Jay Stenger on December 9, 2009 at 13:49:40

Re: Sharp-Shinned vs.Cooper's: I.D. Question posted by Bob Schlake on December 9, 2009 at 19:55:22

Re: Sharp-Shinned vs.Cooper's: I.D. Question posted by Joshua Eastlake on December 9, 2009 at 22:52:32

Re: Sharp-Shinned vs.Cooper's: I.D. Question posted by Jan Watkins on December 10, 2009 at 12:35:30

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	Sharp-Shinned vs.Cooper's: I.D. Question         posted by Joshua Eastlake on December 9, 2009 at 09:37:57
	Earlier this week, I posted a sighting of two sharp-shinned and a kestrel at Armleder. Saw all three in the air at the same time very close to each other, and all three came within 20' of me as they chased each other. The two mature hawks that I assumed were sharp-shinned were just BARELY larger than the kestrel, and seemed much more slight of build than the heftier accipiters that I have seen at Armleder, my backyard, and elsewhere (which I have always assumed were Cooper's). Prior to the aerial battle, I also got to watch one of the "sharp-shinned" sitting in a tree for several minutes, and the tail was very noticeably squared off as opposed to rounded. So here is my question for anyone who might be able to provide insight: Do you think it is reasonable for me to assume that I was seeing Sharp-Shinned Hawks based on the information above? I have looked at my field guides and the Cornell web site, but still don't feel totally confident in my ability to differentiate between the two. I have also always assumed that sharp-shinned were forest birds, and did not expect to see them hunting out in the open like that. Appreciate any feedback you might have to offer...
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	Re: Sharp-Shinned vs.Cooper's: I.D. Question         posted by Jay Stenger on December 9, 2009 at 13:49:40
	Hi Joshua. Not having seen your birds, I am in no position to tell you what you did or didn’t see. The accurate identification of accipters is only one example of the many complexities that birders are continuously challenged with. It can be quite difficult to separate Cooper’s from Sharp-shinned in the field, and many birders, when they are not sure as to the true identity of a given bird, will just record the sighting as an “accipiter” species. You see this often on Christmas Bird Counts. While this approach might not be very satisfying, in the interest of accurate records, if one is not 100% sure, it is the correct way to go. Of course this rule is true of any sighting of any species. Even the most experienced birders will not be able to accurately identify every bird they run across in the field. But only birds that we are 100% sure of should be positively identified to species. This is not to say we can’t remark that we “think” we had, or “might” have had, or “probably” had a particular species. But unless we are 100% certain, we shouldn’t be conclusive. One obvious reason for this conservative approach is that if we are wrong in our ID, then we have contributed to skewing the data for the species in question. There are many subtle clues that differentiate a Cooper’s from a sharpie. The more of these that are seen, the easier it is to clinch the ID. These clues include structure, shape, field marks, flight style, behavior, vocalizations and distribution. Size can be useful, but alone and without other supporting features, usually won’t clinch an ID in the field. Female accipiters are larger than males and because of this, female Sharp-shinned approaches the size of the male Cooper’s. Accipiters are forest birds, but they are not confined to that habitat and are often seen in open areas. And during migration they can be virtually seen anywhere. Cooper’s Hawks are by far the most common year round accipter in our region. They are common migrants and common summer and winter residents. Sharp-shinned Hawks can also occur in our area during any month of the year but are much less common overall. During spring and fall migration (March-May and September-November) Sharp-shinned Hawks can be fairly common. During the summer (June-August) they are extremely rare, with only a few area-breeding records. As winter residents (December-February) in our region they are considered uncommon at best and are almost always seen as individual birds.
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	Re: Sharp-Shinned vs.Cooper's: I.D. Question         posted by Bob Schlake on December 9, 2009 at 19:55:22
	Jay Stenger rocks...........Thanks for all your knowledge shared.
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	Re: Sharp-Shinned vs.Cooper's: I.D. Question         posted by Joshua Eastlake on December 9, 2009 at 22:52:32
	Thanks Jay! Appreciate it very much.
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	Re: Sharp-Shinned vs.Cooper's: I.D. Question         posted by Jan Watkins on December 10, 2009 at 12:35:30
	I'm certainly no expert when it comes to bird ID, but due to our resident Cooper's Hawk, which I've been able to view "up close and personal" at times, I've had the opportunity to compare the tail with that of a Sharp-shinned (using field guides, all of which note the difference in the tail of each, i.e., Cooper's has a longer tail rounded at the corners, often with a wide white band at tip; whereas the Sharp-shinned's tail is more squarish at corners). Sometimes it's more simple to focus on one field mark, if view is brief.
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