My friends expect me to know the names of birds, and I often do—after all, how hard is it to identify a crow or a scrub jay? So far no one has noticed my awkward silence when hawks fly overhead. I’m almost never sure about these birds. Sometimes I just say, “Probably a red-tail,” which is absolutely the safest guess you can make about a soaring bird in our part of the world.
So I’ve been reading Raptors of California by Hans Peeters and Pam Peeters (University of California Press, 2005), and I’ve learned that I’m not the only one who has this problem. Hawks and other raptors are hard to identify! For one thing, there’s scale: how can you tell if it’s hawk-sized or eagle-sized when it’s the only thing in the sky? For another, colors may vary within species: red-tailed hawks, for example, come in light, dark, and rufous morphs, and occasionally there are even “leucistic,” or pure white, individuals. Another difficulty is that female raptors are bigger than males. The difference in size correlates to the speed of the species’ prey of choice: among red-tailed hawks, which hunt mammals, females may be up to 25 percent bigger than males, but among hawks that hunt birds—Cooper’s hawks, for example—females may be half again as big. Adding to the confusion, juveniles look different from adults, and molting alters the appearance of raptors as well. And then they’re usually far away, and if they’re backlit you haven’t got a chance of seeing the details of their patterning. And that diagnostic tail on a red-tailed hawk? It’s only red on top (but you can see the red from below if the sun is shining through it).
The term “raptor” applies to all birds of prey, and that includes owls and vultures. Excluding them for now, the raptors you might see around Contra Costa County are hawks (red-tailed, red-shouldered, Cooper’s, Swainson’s, and sharp-shinned); northern harriers; American kestrels; peregrine and prairie falcons; golden and bald eagles; white-tailed kites; and ospreys. If you’re lucky enough to see a bald eagle, you’ll know it. Golden eagles, besides being huge, have a distinctive golden cast in the sunlight, and often white epaulets. The young ones have large light-colored patches on the undersides of their wings. Kites have a very distinctive look. But it gets complicated when you start trying to identify hawks and falcons.
You can narrow the choices by paying attention to shape. Most raptors fall into three categories: buteos, accipiters, and falcons. Buteos have long, broad wings and relatively short tails. These are the soaring birds, the ones that cruise the air looking for prey and then swoop down on it—red-tailed and Swainson’s hawks, for example. The accipiters’ wings aren’t as long, so their tails are proportionately longer than those of buteos. Cooper’s and sharp-shinned hawks are accipiters, and although the red-shouldered hawk isn’t an accipiter, it’s shaped like one. Unlike the soaring buteos, accipiters chase their prey. Shorter wings make it easier to fly through vegetation, and their long tails, used for braking and steering, give them more maneuverability. Falcons, the third group, have long tails and pointed wings. The northern harrier, which many people know as the marsh hawk, defies categorization, having a long tail and long, blunt wings.
Within those three categories, field marks are helpful. Though colors vary, patterns are somewhat consistent. Looking at a red-tailed hawk from below, you can see the dark patches on the leading edges of its wings that contrast with the lighter feathers and distinguish this bird from other buteos. Good luck telling a Cooper’s from a sharp-shinned hawk, though. I’ll include a link below from Cornell University that goes into great detail about how to do it.
Knowing a few details about the behavior of a species makes all the difference. At the Martinez Beaver Festival last year I overheard one of the staffers at the Lindsay Wildlife Museum’s table say, “Oh, the red-shouldered hawk—you mean the one that never shuts up?” And yes, that did turn out to be the hawk that was making such a racket last spring in some of the wooded areas along the creek. The red-tailed hawk, on the other hand, makes the archetypal raptor shriek, so much so that filmmakers often dub it into the sound track when a bald eagle appears on screen. Really. Harriers have a distinctive way of gliding low over grasslands and then dropping straight down on their prey. Red-tailed hawks often perch on light standards—there was one for years near the Highway 4/680 interchange—but accipiters usually perch within the shelter of trees. And peregrine falcons have famously have found that a tall, sheer building works just as well as a cliff for a nesting spot.
Raptors are very active right now, either courting or already raising their young. The hills are alive with the squeaks of rodents, and on a warm morning they find the thermals over our beautiful open space perfect for soaring. The birds will get less active in summer, and then in fall they will migrate in dramatic numbers. The Marin Headlands are the best-known Bay Area location for watching hawks in migration, but there are a couple of hot spots nearby. Last fall hundreds of Swainson’s hawks stopped over in Byron. And a few years ago, during the return migration, birders watched dozens of raptors at a time—over seven thousand in the course of a month—flying northward through the Crockett hills. Apparently that doesn’t happen every year, but from now through mid-April would be the time to keep an eye out.
Here’s the link about Cooper’s and sharp-shinned hawks.
The Golden Gate Raptor Observatory—“Hawk Hill” on the Marin Headlands—is raptor central for the Bay Area and their website is full of information, including downloadable copies of the annual Pacific Raptor Report.
One of the most thrilling sights possible is a close-up view of a raptor. You can experience this at Walnut Creek’s Lindsay Wildlife Museum, where the rehab program has resident hawks, owls, and eagles, and there are raptor presentations at 1 p.m., Wednesday through Sunday.
Thanks once again to Ethan Winning for the use of his photos. You can see more at his Point and Shoot Nature Photography website.