One of the great natural mysteries for me is how two species (sometimes more) evolve to look so similar and yet not simply be an offshoot of the other. Take Cooper’s and Sharp-shinned Hawks, for example. If I see one or the other in the wild, I really can’t be sure which it is, even though I’m familiar with many of the indicators that pros use to differentiate them. I’m not alone!
For what the Cornell Lab of Ornithology tells us look for, go to their website. Click on items in their list for extra illustrations / details: Cooper’s vs Sharpies – Cornell
Comparative images from another site:
“In the above composite image we can compare a juvenile Cooper’s Hawk (on the left) to a juvenile Sharp-shinned Hawk (on the right). When they are shown side by side, even though they are in slightly different postures, one can see differences, making it easier to work out which is which, rather than when viewing an individual bird.
- The eye looks larger and more foreward in the head on the smaller headed Sharpie. NOTE: CORNELL’S SITE SAYS THE OPPOSITE! “Eyes appear to be close to half way between front and back of head [of the Sharpie].” Just keeping life interesting….
- There is a noticeable dark stripe on the throat of the Cooper’s.
- The colour of the breast pattern – dark brown on the Cooper’s, and, warm brown on the Sharpie.
- The narrower and cleaner markings, tear drops thinning out on the belly, on a Cooper’s, versus, heavier or coarser and blurrier markings on the Sharpie.
- Broad barring on the flanks on the Sharpie.
- Thick sturdy legs (tarsi) on a Cooper’s while they are delicate and pencil-thin on a Sharpie.
- Though we can’t see the tail on the Cooper’s, it is usually rounded compared to the squared-off tail of a Sharpie. While that can be easier seen in flight, when posing upright one can see that on a Cooper’s, each tail feathers get shorter towards the outer feather” giving it a rounded look when spread in flight.” (from the Wildside)
So what’s this one, then?
This one has my Flickr friends giving me opposing labels. I think it’s an adult Cooper’s, but I’m still not sure….
From these lists, items that are easiest to examine are tail feathers, eye position, and head shape and cap, and in juveniles, breast markings. Size, it turns out, isn’t very reliable, as male Cooper’s are relatively small and female Sharpies are relatively large, so even though we know that Sharpies are generally noticeably smaller than Coops when comparing the same gender, it’s a problem when we can’t be sure which gender we’re looking at, and there’s no reliable way in the field to differentiate the males from their mates.
So, even knowing a few identifiers, I often have to wait until I get home and look at the images to make my guess — and then wait until after I’ve posted and real experts weigh in….
Sharpies range through more of Canada than Cooper’s do. Click either image below to enlarge it.
It’s always exciting to come across either species. While not rare, they’re not a bird that I can expect to see on a regular basis, or at least, they weren’t until I moved to Kelowna. Here, their territories are a little easier for me to pin down than they were at The Coast. This winter, J L Cummins, a birder-photog colleague in Washington State, has enjoyed having a Sharpie in his backyard, and it has become as familiar to him as Kessie, the female American Kestrel has become for me. Perhaps the Cooper’s / Sharp-shinned that I see several times each winter and spring in our neighbourhood will become as identifiable as Jim’s….
So, I’ll wrap up this discussion of uncertainty with some photos taken in the neighbourhood:
In January 2017 I had a great but unexpected opportunity to photograph the hawk below. Sadly, my camera settings were right for a previous photo I’d taken of a distant Red-Tail, and woefully wrong for this guy/gal. Surprisingly, when I posted it on Flickr anyway, it got far more hits and positive comments than it deserves. It’s here simply because, at the time, I promised myself that if I got another chance, I’d do much better…. See the next one….
And finally, on March 8, 2017, I did get my “another chance.” Guided by instinct, at about 10 AM I entered Belmont Park from the east so I’d have the light behind me. The Park was extremely quiet, as it often is when there’s a hawk about. Just after I passed a small fir on my left, I heard a flapping of wings and figured I’d flushed one of the Mourning Doves that frequents the area. Then I saw the hawk as it veered into perch on a pine about 20 meters in front of me. I got the shot, and, right or not, am calling it a Sharp-shinned. Click on any of the photos to enlarge it.
Hope you got this far and that you enjoyed looking at these powerful and handsome hawks!