A Nature Behind the Common:
Red-tailed Hawk Species Profile

By Paul Grindrod, HWI Outreach Coordinator

It seems that with regard to nature, familiarity often breeds contempt, or at least indifference. Take the case of the Red-tailed Hawk, Buteo jamaicensis. It is the most common large hawk in North America and occurs in 14 to 16 subspecies (depending on the taxonomic authority), from Alaska to Florida, through Central America, and scattered across the islands of the Caribbean Ocean. Sometimes persecuted as a "chicken hawk" (despite preying predominantly on mammals), it is often misidentified, particularly in immature plumage when it lacks the distinctive red tail that gives the species its name. The Red-tailed Hawk is easily overlooked in our own backyards, parks, and fields.

What David Sibley calls "the buteo to which all other buteos are compared," the Red-tailed Hawk is the quintessential soaring raptor, with long, broad, rounded wings and a short tail that can be widely fanned. It is one of 28 species in this comparatively large and widely dispersed genus-the true "buzzards" of the Old World. Others include the Common Buzzard, Buteo buteo, of Europe and Asia; the Rough-legged Hawk, Buteo lagopus, which occurs all around the Arctic; several Neotropical species in Central and South America; and island endemics from the Galapagos Islands to Madagascar.

Represented by Seven Subspecies

In the continental U.S., the Red-tailed Hawk is represented by up to seven subspecies. They are broadly delineated by geographic distribution and more or less distinguishable by tail color or markings, overall coloration, presence or absence of key field marks (principally on the ventral surface), and size. Subspecific classification becomes a jigsaw puzzle of nightmare proportions due to the range of color variations within and between recognized subspecies. This variation is called "polymorphism," or to designate multiple color morphs, "polychromatism." All subspecies interbreed where they overlap. This further complicates the recognition of valid subspecies for the expert as well as for the casual observer.

A large, powerful buteo, the Red-tailed Hawk stands 17 to 25 inches high with a wingspan from 3.5 to 4.5 feet. They weigh anywhere from 2 to 3.5 pounds. Females average somewhat larger and heavier than males, although large males may overlap small females in any given measurement. Accurate sexing is so difficult that the Bird Banding Laboratory does not accept sex information for red-tails at all.

Tail Coloration Varies with Age

Tail length and coloration vary with age. Immatures have slightly longer tails, banded in light and dark brown to grayish bars. After the first molt, a year after hatching, they get the red tail. Adult tail feathers are slightly shorter (wingtips on a perched adult reach or nearly reach the tip of the tail in most subspecies). Typical eastern adults have brick-red tails with a single dark sub-terminal band and a white tip, while western adults have red tails with up to 7 to 9 dark bands. The red color is only on the top surface of the tail, but can still be seen from underneath if the tail is backlit. The wings are broad and rounded. The four outer primaries are deeply notched giving a "fingered" appearance. Red-tails soar on flat wings, although in straight-on flight the dark tips often curl up slightly. In a full soar, the slightly longer secondaries bulge beyond the primaries, as though the bird is flexing a muscular bicep.

Because the full range of plumage variation is beyond the scope of this profile, this article summarizes the typical field marks of the more common and widespread variants. The generic light-morph adult has a dark head, lighter breast (clear white to streaked with reddish), and a dark belly band. Eastern birds often have a white throat; western birds do not. Most are dark, chocolate brown on the back and top surface of the wings. When perched, they frequently show a white or pale buffy "V" on the scapular feathers, from the shoulder to the base of the tail. When seen in overhead flight, the wing linings are pale off-white to rufous, flight feathers finely barred, and with distinct dark comma shaped marks at the carpal (wrist) joint. At the leading edge of the wing, where it meets the shoulder, there is a very dark crescent mark called the patagium. No other North American raptor has so pale an underwing with this contrasting dark mark. The tail appears whitish from below except when backlit; the presence or absence of barring seen through the tail distinguishes western from eastern birds (as described above). A belly band may or may not be visible depending on subspecies and individual variation. Juveniles are much like adults with the following exceptions: the dorsal surface of the tail will not be red, and the breast is usually much cleaner white.

Dark-morph birds are more common in the West than in the East. The darker plumage obscures the contrast between the breast and belly band, and covers the patagial crescent on the underwing. Birds appear uniformly dark, but adults have a red tail while juveniles have a banded tail.

Taking Prey

These highly adaptive hawks are found in any semi-open to open country, coniferous or deciduous woodland edge, farm fields and shelterbelts, as well as golf courses, cemeteries, and similar urban park-like habitats. The key to this habitat association is a mix of trees for nesting and perch hunting and open areas for securing prey. Given the range of distribution and habitats, it is not surprising that Red-tailed Hawks also take a huge range of prey. Mammals - including mice, voles, and rats, tree and ground squirrels, gophers, rabbits and hares - can account for over 80% of the diet. Birds, snakes, insects, and crustaceans make up greater or lesser parts of the diet depending on local abundance. Red-tailed Hawks will also eat carrion if that is what is available.

Most prey is taken in a short flight from a high perch. Other flight styles include the ability to hover, briefly, and a far more common activity called "stilling" or "kiting." Hanging apparently motionless on a prominent ridgeline, the bird is actually soaring into a headwind that holds it static relative to the ground.

Migration and Conservation

While not all Red-tailed Hawks are migratory, they are often among the four or five most common species at migration count sites. More northerly populations will leapfrog populations to their south. Young of the year will always disperse from the natal territory, and conventional radiotelemetry and satellite telemetry projects by HWI and others are bringing to light some interesting and often surprising movements.

Eastern migration counts between 1940 and 1970 show as much as a 70% increase in Red-tailed Hawks. Likewise, long-term HWI migration data for the interior West, western Christmas Bird Count data, and western Breeding Bird Surveys indicated stable to increasing trends through the mid-1990s. These increases probably reflect expanded availability of mixed woodland and open habitat due to logging and rural development. Telephone poles and electric distribution lines also appear to have allowed red-tails to expand their foraging and nesting ranges into areas that previously lacked perches, possibly at the expense of Ferruginous Hawks or Golden Eagles, both of which are open area specialists. This type of human-caused increase is not necessarily a positive thing, since it may cause a shift in animal community structure by favoring red-tails over other, less adaptable species.

We are lucky to have this majestic raptor so readily at hand. Neither so speedy as a peregrine, nor so symbolic as an eagle, it is the one raptor that we are most likely to see day to day. Whether on a lintel overlooking Central Park West (see Marie Winn's book Red-tails in Love), a fencepost in rural Kansas, or a telephone pole in California, red-tails remind us that there is still something wild out there to connect us to nature. If you get to know them, you may find them just outside your window.