Wing and a Preyer

The power and beauty of a soaring hawk is as much a part of the Los Angeles landscape as mountains and freeways. It’s an unlikely juxtaposition of wild predator and urban setting.

There are several species found in Los Angeles, but by far the most common is the red-tailed hawk. Often seen soaring in twos (usually a mated pair), or perched on utility poles, red-tailed hawks are synonymous with the area, especially the San Fernando Valley. A red-tail even graces the city seal of Calabasas, where the hawks are abundant.

Red-tailed hawks are amazingly adaptable, said ornithologist Kimball Garrett, and may be seen in most parts of the city, even downtown L.A. Most are year-round residents and are expert hunters, helping keep the rodent population in check.

Hawks are birds of prey or raptors, which comes from the Latin verb rapere, to seize. Topanga conservation biologist Sean Manion said red-tails are especially active in the spring, when they need to feed hungry nestlings, and when reptiles--a staple of the hawk diet--come out of hibernation. Manion has even found rattlesnake rattles in abandoned red-tail nests.

Although red-tailed hawks aren’t threatened or endangered, they are protected and it is illegal to harm them, or even take a feather. While their population is healthy, Manion says decreasing habitat is potentially bad for hawks. “In Southern California, [habitat] fragmentation is always occurring, which is debilitating and deleterious to wildlife populations.”

*

Red-Tailed Hawk (Buteo jamaicensis)

Features: 19 to 25 inches long (female is larger than male), with 4-foot wingspan. Color varies from a white chest with dark brown back to an overall color of brownish-black. Belly usually has a dark band. Broad, rounded tail is rusty-reddish brown, distinguishing it from other hawks.

Diet: Rodents, small mammals and birds.

Nest: Platform of sticks or branches in tall trees or cliff faces. A clutch of two or three eggs is laid February to June.

Habitat: Because they’re aerial hunters, red-tailed hawks prefer open grasslands and chaparral. Often seen circling fields or perched on utility poles.

* All hawks have strongly curved beaks. Nostrils are located on the fleshy section of the upper beak.

* Nostrils are located on the fleshly section of the upper beak.

*

Wingspan

Condor: 9 feet

Golden eagle: 7 feet

Red-Tailed Hawk: 4 feet

*

Masters of Flight

Their broad wings and short tails allow red-tailed hawks to be expert soaring birds. The same aerodynamic principles that apply to airplane lift also apply to hawk flight.

In flight, hawks are constantly adjusting their primary feathers--the strong, pliable flight feathers on the outer “hand” portion of the wing.

Tail adjustments are made constantly in flight, similar to the adjustments to an airplane’s rudder. This is why red-tails are most likely to be seen where there is some landscape relief features such as ridges and hills.

*Primary Feathers: The finger-like primaries are kept pointed when going into a dive to capture prey, or are spread like fingers when soaring.

* Long, broad wings provide good lift surface, similar to the wings of an airplane. The inner part of the wing supplies lift; when a hawk soars it holds this part slightly upward and forward.

* Red-Tail hawk flight pattern: Red-tailed hawks are continually positioning themselves to take advantage of thermal currents, the rising warm air along raised landscape.

*

Hunting on the Wing

Unlike some other raptors, such as falcons, which knock their prey out of the air and eat on the fly, hawks feed primarily on the ground. A red-tailed hawk will soar from a height of hundreds of feet, scanning the ground for small prey and then diving to snatch its prey.

* Hawks pull their wings close to the body when diving, forming a bullet shape to increase speed.

*

Hawk Eyes

All birds are equipped with monocular (one-eyed) and binocular (two-eyed) vision, but hawks have a wider range of binocular vision. Hawks have perhaps the sharpest vision of any living creature, but it’s a misconception that they have zoom-like eyesight. Hawks do have a much denser set of visual cells on their retina than humans. More retinal cones--minute visual cells that operate in daylight--allow hawks to receive sharp visual images. They can detect light, shape and movement better than other creatures can.

Sources: Kimball Garrett, ornithologist, Natural History Museum of L.A. County; Sean Manion, biologist, Santa Monica Mountains Resource Conservation District; “The Audubon Society Encyclopedia of North American Birds”; “Hawks: Hunters on the Wing”; California Wild magazine.

Researched by JULIE SHEER/Los Angeles Times.