Twenty-four Ways to tell Sharp-shinned Hawks and Cooper's Hawks Apart

[Above and below: one's a Sharp-shinned Hawk, the other a Cooper's Hawk. Not necessarily to scale; few photos are, and also consider how different lighting conditions, bird postures and photo processing might have affected the photos. Use the chart below to figure out which is which. I confess I didn't pick slam-dunk photos, but these are still readily i.d.'d. Both Cape May, NJ in fall. Click to enlarge.]

This is FAR from a new i.d. challenge. Back in the early 1980’s, when I first became involved in “organized” birding, it was very, very common for people to just let these i.d.’s go as Accipiter sp., Accipiter being the Latin genus for these two, plus Northern Goshawk, which I’m ignoring here but have written about before, and besides, if you see an accipiter, it probably is not a goshawk. (And let’s not forget there are Accipiter species on other continents.)

We've gotten way better at sharpies and coops, but anyone who tells you they have no trouble telling these two apart is at best wrong and at worst a liar. Everybody gets a few wrong. Want a story? Okay, here’s one. A mid-May dawn, standing at the edge of a wood at the base of a hill with my friends and team for the World Series of Birding, at the time the premier birding competition on the planet (no longer true). The team was me, Pete Dunne, Richard Crossley, Will Russell, and I think Michael O’Brien that year. You probably know of these guys. There was a whole lot of birding horsepower standing at the base of that hill waiting for a Ruffed Grouse to drum.

An accipiter blew out of the dawn woods and flew right over us, maybe 100 feet up. I cursed under my breath and muttered, “Sure was a good thing I spent 4 afternoons this week finding our Cooper’s Hawk nest.”

I’m not going to share who said what.

“How it goes.”

“At least we don’t have to bend the route to go after the other Coop now.”

‘I wonder where this one is nesting?”

And, finally, “[expletive deleted] That was a Sharp-shinned!”

Yep.

Unless you do a lot of hawk watching, you don’t see a lot of accipiters. Somewhere I read about this “rule of 10,000,” which says all you need to do to get good at something is do it 10,000 times. There might be some truth to that, but what probably works just as well on accipiters or anything else is try to identify some, realize you can’t, begin to realize at least what questions you need answered, and then talk to people, read up, look at pictures, all the while continuing to look at actual birds. And keep your mouth shut until you have applied every field cue available to you. I know, I know, this spoils the glory of being the ace first to the i.d., but better to be slow and right than fast and wrong.

Maybe you’d only need 5,000 tries to get good at SSHA vs. COHA. Those are their four letter banding codes, by the way.

Before taking a shot at the following chart (which actually presents 28 different things to look at, I just lumped a couple), two things must be remembered. First, identifying a photo of a bird is very different from identifying a bird. If all you have is a photo, you cannot necessarily judge shape or structure (because you don’t know what the bird and the wind are doing), color (if you don’t believe me, fool with the exposure and saturation sliders in Lightroom or Photoshop or whatever software you use), or behavior (duh). Hopefully the photographer was kind enough to tell where and when the photo was taken, because without that information, identifying photos is a nightmare exceeded only by identifying bird sound recordings without that same information.

Second, plumage cannot be used to identify these or any other birds unless you age them first. There are photos below to help. Adults of both Sharp-shinned Hawks and Cooper’s Hawks have slate gray backs and breasts with orange bars. Juveniles (also called first years or immatures) have brownish backs variably flecked with white or buff, and breasts with brown streaks. Bars go side-to-side, streaks go up and down. Remember it this way: when you leave the BAR you stagger side-to-side. When you go STREAKing, um, things go up and down.

Okay, here we go. The most important stuff is italicized :

	TRAIT	Sharp-shinned Hawk	Cooper’s Hawk
	Size, Shape and Structure
1.	Head	Proportionately small, projects little beyond leading edge of wing in flight (accentuated by wrists jutting forward), looks a bit like it was just stuck on whether in flight or perched; never looks crested.	Proportionately large, projecting noticeably beyond leading edge of the wing in flight (accentuated by a clean, straight leading edge of the wing); sometimes looks crested at rear.
2.	Eye position on head.	Throw this one away, would you? It just seems unreliable, not to mention useless in most field views. In photos, you can’t tell if the head angle is pure profile view or slightly canted towards or away, which blows the whole eye position thing up.	Same. Supposedly, the eye on a Sharp-shinned is more centrally positioned and on Cooper's it is placed forward towards the bill. But, if a coop flattens its crest, apparent eye position changes, as it does in a photo or look at a bird that is not quite in profile. Toss this one.
3.	Wing in flight.	Proportionately shorter; juts forward at wrist in flight, when gliding, and a bit when soaring; a bit more of an “S” shape on the trailing edge than Cooper’s. See wingbeat below.	Proportionately longer; quite straight along leading edge (except if in a hard glide or active flight, when wrist juts forward, which is why you can’t use this in a photo unless the bird is soaring); straighter trailing edge. See wingbeat below.
4.	Tail You may be a happier person if you stop using tail shape for telling these two apart most of the time.	Not “graduated” (meaning SSHA  outer tail feathers are the same length as the inner ones); usually appears straight cut across the tip with squared off corners (beware Sharp-shinneds with worn tails); sometimes appears proportionately shorter than Cooper’s.	“Graduated,” meaning COHA outer tail feathers are shorter than the inner ones; usually appears rounded, sometimes markedly so (beware Cooper’s with worn tails); sometimes appears proportionately longer than Sharp-shinned, perhaps because trailing edge of wing is straighter.
5.	Undertail coverts	White but not prominent or flared.	White, fluffy, sometimes flared. Cooper’s Hawks have been called Northern Harriers by the unwary.
6.	Body	Skinny unless it just ate.	Some say it is the slender accipiter, but I think thicker, fuller bodied than SSHA (though nowhere near as full as goshawk); sometimes called "tubular." 3X as heavy as SSHA.
7.	Legs and feet	Well-named; eensy beensy skinny legs and small feet. Great field mark for the one sitting on your bird feeder.	Thick legs (think diameter of a pencil), big strong feet, looks like it could kill a squirrel, which they sometimes do. Great field mark for the one sitting on your bird feeder.
8.	Overall size (females are larger than males in both species but there is no size overlap between the species. Size measurements are averages from the Sibley guide.	Small. Some males look cardinal size, but some females look Cooper’s size. Length: 11” Wingspread: 23” Weight: 5 oz. (For an American Robin, the same dimensions are respectively 10”, 17”, 2.7 oz.	Bigger. Some males look Sharp-shinned size. Some females may look goshawk size, but not ever even close. Length: 16.5” Wingspread: 31” Weight:16 oz. (For an American Crow, the dimensions are respectively 17.5”, 39”, 16 oz.)

 

#	TRAIT	Sharp-shinned Hawk	Cooper’s Hawk
	COLORS AND PATTERNS (you MUST age the bird first to use plumage!)
	Breast (adult)	Barred orange-brown.	Essentially the same.
9.	Back (adult)	Slate gray, not “capped.”	Slate gray with dark cap.
10.	Tail (adult & juvenile/first year)	Whitish-gray with dark bars, tipped thinly with gray.	Whitish-gray with dark bars, tipped prominently with white unless feathers are worn.
11.	Breast (juvenile/first year)	Thick brown streaks all the way down the breast, as if made with a standard magic marker. Looks dusky- or dark-breasted at distance.	Narrow or fine brown streaks, usually quite thin at center of lower belly, as if made with a Sharpie marker (ironically). Streaks are often teardrop shaped.
12.	Back and head (juvenile/first year)	Brown, variably flecked with white or buff spots, tends to appear colder toned than cooper’s Hawk, does not show a tawny nape, does not look hooded, often shows an obvious pale supercilium (eyebrow).	Brown, variably flecked with white or buff spots, tends to appear warmer toned than Sharp-shinned Hawk, often  shows a tawny nape, often looks like it has a hangman’s hood, supercilium usually less prominent than SSHA..
	Iris (adult)	Red	Red
	Iris (juvenile/first year)	Yellow	Yellow
	Legs and feet (all ages)	Yellow	Yellow

 

#	TRAIT	Sharp-shinned Hawk	Cooper’s Hawk
	BEHAVIOR
13.	Wingbeat The old standard “flap-flap-flap-glide” description for Accipiter wingbeats remains apt. (Highly dependent on wind conditions; they beat more in the wind. )	Quick, snappy; can’t count beats; beats more often than Cooper’s; appears loose as if it has two hinges, one at body and another at wrist.	Stiffer, as if it has just one hinge at the body; beats less often than Sharp-shinned. In display flight, stiff-winged and slow, like a Short-eared Owl, often with white undertail coverts flared.
14.	Soaring behavior (Highly dependent on wind conditions, they soar less in the wind.)	Soars less; soars in tight circles; gets knocked around by gusts.	Soars more; soars in wide circles; steadier than SSHA in gusts.
15.	Perching behavior	Tends to perch beneath the canopy or otherwise more hidden, probably worrying about becoming someone else’s meal.	Readily perches in the open, including on the flat tops of posts which SSHA tends not to do. If you got a perched photo, it was likely a Cooper’s unless at your feeders.
16.	Habitat when not migrating.	Prefers denser forests and denser cover. In winter, neighborhoods with feeders are just fine.	Uses everything, including suburbs, for nesting. In winter, neighborhoods or open landscapes with patches of trees and hedgerows are fine.
17.	Geography	Widespread, gets farther north than Cooper’s. Look at your field guide’s range map.	Widespread. Look at your field guide’s range map.
18.	Probability in migration.	Leans to Sharp-shinned.	Leans to Sharp-shinned, but do not discount Cooper’s Hawk as was done historically.
19.	Probability outside of migration.	At feeders, equal chance of SSHA and COHA. In dense woods, leans to SSHA. In more open habitats, leans to COHA. If you get a perched photo away from feeders, leans heavily to COHA.	Same as at left.
20.	Food	Small birds	Small birds, large birds, loves chipmunks, occasionally squirrels, known to kill SSHA.
21.	Nest	Looks like a couple handfuls of sticks thrown into the crotch of a tree, small, usually in a dense grove, usually of conifers.	More substantial, loves white pines but uses many other trees.

 

#	TRAIT	Sharp-shinned Hawk	Cooper’s Hawk
	Voice
22.	At nest	You can’t use “kek” to describe it. A whiny, wimpy, high “keee-ew kee-ew keee-ew,” please don’t hurt us, please go away.	“KEK KEK KEK KEK KEK KEK.” Get the fug oughtta here. Like they’re from Philly.
23.	Begging, usually at or near nest but sometimes later into fall.	High “kiew,” sometimes repeated.	Lower, demanding “kieew,” often repeated.
24.	Others	Occasionally gives calls associated with nesting year round.	A very sapsucker-like mew, but louder or stronger than sapsucker, occasionally repeated (caution: jays readily imitate this).

[Above, one tail of a Cooper's Hawk, one of a Sharp-shinned Hawk, both captured for banding. Use the chart above to decide which is which. Click to enlarge.]

 [Above, adult Cooper's Hawk. Below, Juvenile/first year Cooper's Hawk. Look at those big feet! And graduated tail. See chart above for how to age these species, and other field marks. Click to enlarge.]

[Above, perched Sharp-shinned Hawk , cell phone photo by Brea Saunders. Notice how thick the streaking is, and the eyebrow. Below, same bird, dorsal view. Look at how the eye position changes with angle. And notice how apparent head size changes with position and angle, and that's a "good" field mark!]

[Above, tellingly, after a fair bit of searching my photos, I did not find an image of my own of a perched Sharp-shinned Hawk. I know I've got a few, but with  >100,000 keeper bird images it'll take some looking, so this shot will have to suffice to demonstrate the sharpie's skinny legs and feet. And, if you can sort out the black thing, you can do this one on size.]

Summing up this i.d. challenge,

"The problem is all inside your head, she said to me,
The answer is easy if you take it logically. . . .”
(Apologies to Paul Simon)

[Note: this article is available as a program or keynote for festivals, bird clubs and organizations, with or without projected images, that delves into this i.d. challenge and the general thought process behind any bird i.d. By and © Don Freiday.]