By Sophia Landis
“Is this a Cooper’s Hawk or a Sharp-shinned Hawk?” This is one of the most frequently asked questions when it comes to raptor ID – and for good reason! Cooper’s Hawks, Sharp-shinned Hawks, and the rarer Northern Goshawk make up North America’s share of the accipiter genus. Before we get into the nitty gritty of how to ID these species separately, let’s take a look at what they all have in common.
Accipiter Build and Behavior
Unlike large and bulky buteos, accipiters have a slimmer overall look highlighted by their long tails and short, rounded wings. This build is essential for their lifestyle, particularly their hunting techniques. Rather than soaring over open fields looking for prey, these woodland hawks often hide in trees, waiting to dart through the branches to snatch unsuspecting prey. Their sleek build allows them to dart through very dense cover if a chase calls for it. Accipiters typically live and breed in the woods. However, they specialize in hunting other birds, which often leads them (especially Cooper’s Hawks and Sharp-shinned Hawks), to backyard birdfeeders. Please try not to be too upset – every bird needs to eat!
When trying to ID an accipiter on the wing rather than in a tree, one helpful identifier is their flight pattern. Whereas many other hawks are seen soaring with wings steady and set, accipiters often fly with intermittent flapping and gliding. At our Decorah hawk banding station, we like to refer to this as, “Flap, flap, gliiiiide! Flap, flap, gliiiiiide!”
Northern Goshawk in flight. Photo credit: J. Ligouri
Juvenile or Adult Accipiter?
From day one, all accipiters start a similar journey: growing their juvenile plumage! Before gaining the blueish-gray back and horizontal breast streaking of adulthood, accipiters have browner plumage with vertical breast streaking. The streaking on all juvenile accipiters is typically dark brown, but adult Goshawks develop gray horizontal streaks while adult Cooper’s Hawks and Sharp-shinned Hawks develop rufous horizontal streaks. This change of plumage begins at first molt. Eye color can also help indicate age, since juvenile accipiters are typically born with pale yellow eyes that turn orange or red as they grow older.
The accipiters at left are juveniles, as indicated by their vertical breast streaks, pale eyes, and browner plumage. The accipiters at right are adults, as indicated by their darker eyes and greyer plumage. Click each picture to enlarge it.
Coopers Hawk, Sharp-shinned Hawk, or Goshawk?
Though all three North American accipiter species have a similar look, the Cooper’s Hawk and Sharp-shinned Hawk (as previously mentioned) are undoubtedly the most difficult to distinguish from each other. They are also much more common in North America than the elusive Northern Goshawk. Here are a few helpful clues that will help you discern which hawk you are looking at.
Location, location, location, and season!
While Northern Goshawks are found year-round in the northern half of the continent and Rocky Mountain area, some migrate to the lower 48 states for winter. Sharp-shinned Hawks can be found across nearly the entire continent, at least seasonally, and breed throughout much of Canada. Cooper’s Hawks are also quite common, inhabiting almost all of the lower 48 year-round. Check out this website for more information on what birds you may have in your area each season (simply search the species you’re curious about): https://www.birds.cornell.edu/home.
You can also ID these hawks by sizing them up. With a length of 9-13 inches and weighing in at just 3-8 ounces, Sharpies are the smallest hawks in North America. Male Sharpies are considerably smaller than females (as is often the case in raptor species), and larger female Sharpies can sometimes be comparable in size to smaller male Cooper’s Hawks. Cooper’s Hawks range from 14-19 inches in length and 10-24 ounces in weight. Goshawks are the largest of the three, ranging from 18-24 inches in length and 24-34 ounces in weight. Again, with a small male Goshawk and a large female Cooper’s Hawk, there could be a bit of overlap in size. Though size comparisons can be helpful, thankfully there are other ways to distinguish these birds.
Field Marks: Heads and Tails!
A helpful “heads up” is the shape of their head. Sharpies have rounder heads that seem to protrude less in flight than Cooper’s Hawks, who have a larger and more block-shaped head. Goshawks have a square-ish look to their head as well, but their heads appear smaller than Cooper’s Hawks due to their broad shoulders. Cooper’s Hawks, and especially Goshawks, also have a distinct gray “cap.” In addition, Sharpies appear to have larger eyes in comparison to head size than Cooper’s Hawks or Goshawks.
At the tail end of key ID clues is the tail itself! Though all three species have long, banded tails with a narrow white tip, there are a few subtle differences. A Sharpie’s tail, though slightly narrower, appears more squared than the other accipiter species. Also, the white tip on a Sharpie’s tail is usually narrower and can even appear to be absent due to feather wear.
Keep looking up!
So when looking to the sky or in a tree at an accipiter in question, remember to consider: range, season, size, head, and tail! And when all else fails, simply enjoy being in the company of a majestic, apex predator. It’s not every day one gets to experience that! (Unless you are very, very lucky.)
For further information on raptor identification, check out The Crossley ID Guide: Raptors by Richard Crossley, Jerry Liguori, and Brian Sullivan; Hawks from Every Angle by Jerry Liguori; and/or Hawks in Flight by Pete Dunne, David Sibley, and Clay Sutton. If you have a smartphone, consider downloading the free app, “Raptor ID.”