Michigan, Hawk ID help please (1 Viewer)

[Hainan on the fly]

I have a really difficult time with similar looking hawks. I think my choices are either Cooper's or sharp-shined here with Cooper's being more geographically common. Any advice on separation criteria on these hawks would be greatly appreciated.

Thanks,

Brian

edit: New higher resolution picture added after first comment from Butty. Sorry for the confusion this added to the thread. I'd made the edit in seconds and didn't realize it had any views at that point.

 

[Butty]

Yes - (an immature of) one of those two Accipiter species - but photo-quality is too low to be sure which (no offence). Seeing the underpart pattern and structure of forehead/bill and tail-tip are the most useful things. But it looks quite chunky and big-headed so I'd guess Cooper's hawk.

 

[Hainan on the fly]

Yes - (an immature of) one of those two Accipiter species - but photo-quality is too low to be sure which (no offence). Seeing the underpart pattern and structure of forehead/bill and tail-tip are the most useful things. But it looks quite chunky and big-headed so I'd guess Cooper's hawk.

Thanks Butty! Really appreciate your insight. This was a quick iPhone pic from outside my kitchen window. Does it become easier to separate these Accipiters in their adult plumage? Any idea of what subspecies of Sharp-shinned occurs in Michigan?

Thanks,

Brian

 

[Butty]

Adults are about as difficult as immatures. Structural differences are the same, and on adult Cooper's hawk look also for crown darker than upperparts and pale sides to hindneck.
In most birds, the subspecies isn't interesting - it doesn't tell you anything, and (except sometimes for migrants) a given bird will just be whatever subspecies is present in that area. I've no idea what your local Accipiter subspecies would be.

 

[nartreb]

What Butty said. I also lean toward Cooper's both based on impression of head size, and because I think I can see enough of the tail tip that it looks more cooper-like than sharpie to me.

Does it become easier to separate these Accipiters in their adult plumage?

No. In juvenile plumage it's arguably easier, if you get a really good view of the belly streaks. (There's a subtle difference in the streak thickness, though this shouldn't be relied on too much since the streaks can look quite different depending on how much the bird is fluffing its feathers.)

Any idea of what subspecies of Sharp-shinned occurs in Michigan?

I'm sure one could look it up, but I doubt I'd have any chance at distinguishing subspecies anyway, so personally I've never bothered.
OK, I looked. There's some debate about the proper number of species or subspecies, which is not exactly an unusual situation in biology. The current majority view is that there's one species covering both North and South America. All the birds that breed in the US would fall under subspecies striatus.
At least three other subspecies divide up Central and South America along with the parts of the Caribbean not occupied by striatus. Some of them are actually distinguishable by appearance.

 

[Butty]

For some reason (let's not worry why) I can suddenly see your photo at much higher resolution - and it's definitely a Coopers hawk: big bill, sloping forehead, blocky rear head-shape.

streaks can look quite different depending on how much the bird is fluffing its feathers

Oh, I wouldn't agree. For immature Cooper's hawk one goes on the thinness of the streaks on lower central belly compared with thicker streaks/blobs higher up - and each streak is a mark on the centre of each feather - hence the thickness of individual streaks is unaffected by plumage ruffling. I've never noted that plumage ruffling affects the visibility of this.

 

[Hainan on the fly]

For some reason (let's not worry why) I can suddenly see your photo at much higher resolution - and it's definitely a Coopers hawk: big bill, sloping forehead, blocky rear head-shape.

Oh, I wouldn't agree. For immature Cooper's hawk one goes on the thinness of the streaks on lower central belly compared with thicker streaks/blobs higher up - and each streak is a mark on the centre of each feather - hence the thickness of individual streaks is unaffected by plumage ruffling. I've never noted that plumage ruffling affects the visibility of this.

Hey sorry Butty, I did upload a replacement picture seconds after when I looked at the image quality. I didn't see any views at that point and I thought I snuck the edit in.

 

[KC Foggin]

I agree with Cooper's.