We can loosely separate the diurnal (daytime) raptors into three groups. First are the soaring hawks (buteos) and eagles. We've all seen them. They are the large-bodied ones with the long, broad, rounded wings soaring and circling above mostly open landscapes. Next are the falcons. Known for their streamlined appearance, these are birds which display speed and agility on pointed wings. The contrast between these two groups is roughly similar to that between long-range bombers and fighter jets.
The third group, known as accipiters, is curious. A sort of cross between the previous two, the three North American representatives are quick-striking, bird-eating hawks which favor forest habitats. Clark and Wheeler, coauthors of the book "Hawks of North America," describe accipiters as, "...aggressive, capable of rapid acceleration, and agile and reckless when in pursuit of their prey."
When asked what he thought of accipiters Ben Schwartz, a master falconer, said, "They are the most ill-mannered, unpredictable, hard-to-work-with birds of them all. But the dynamic nature of their hunting style is very interesting to be a part of."
One accipiter - the Cooper's hawk - has become a common nesting species in parks and neighborhoods in and around our area but mostly departs for the winter. The largest and least seen is the northern goshawk. Glimpsing one of these giants in the Fargo area is a treat, as the bird does not nest here and is rarely seen in migration. That leaves the smallest of the three, the sharp-shinned hawk (Accipiter striatus).
"Sharpies" have blue-gray backs and wings with long, barred, and squared-off tails. Its white front is heavily barred in reddish tones. The hawk gets its name from a bony ridge which runs the length of its skinny legs. About the size of a pigeon, the birds are strikingly similar in appearance to Cooper's hawks. So similar in fact, the difficulty in separating the two species has generated thousands of words of printed material over the years.
One overriding factor which mucks up the process is size. Clark and Wheeler say, "Sexual dimorphism, with females much larger than males, is pronounced in this genus." So we have four differently sized birds (Cooper's hawk male and female and sharp-shinned hawk male and female) all with very similar appearances.
But here's a quick and dirty primer on distinguishing the two. Keep in mind no single attribute should be taken as definitive. Instead, the characters should be treated in toto.
Cooper's hawk: large, usually a more rounded tail, larger head, tail appears longer, thicker legs, blackish cap usually contrasting with back color, commonly raises hackles, seen locally usually in summer, and "countable" wing beats.
Sharp-shinned hawk: smaller, squared off tail, smaller head, shorter tail, skinny legs, cap doesn't contrast with back color, rarely raises hackles, seen locally usually in winter, and wing beats mostly too quick to count.
Got all that? No, it isn't an easy call. Author Kenn Kaufmann even writes, "The real expert knows when to say, 'I don't know.'"
Sharpies have a habit which doesn't endear themselves to every homeowner. It's a frequent visitor at bird feeders. Recently a female made daily appearances in my target-rich back yard for two weeks. She would sit patiently and quietly in a tree and wait for a small songbird to wander in unwittingly. At other times she would boldly blast through the yard in hopes of scaring up prey (Pete Dunne refers to the bird as "the artful dodger"). I never saw it successfully catch a bird but there were attempts. Just witnessing the chase was thrilling enough.
Over the long winter months we tolerate a pronounced lull in most wildlife action. We should savor any vestige of activity including visits from sharp-shinned hawks. These tiny peeks into the give-and-take of the natural world might be just enough to escort us into the spring months. Moreover, they allow us to feel a part of the process even if it's only as an observer.