Harris Hawk

SCIENTIFIC NAME

Parabuteo unicinctus

CLASSIFICATION

Class:	Aves
Order:	Falconiformes
Family:	Accipitridae
Genus:	Parabuteo
Species:	unicinctus

SIZE

Length:	Male:	17.5-24 inches
	Female:	17.5-24 inches
Weight:	Male:	1.4-1.9 lb.
	Female:	1.4-2.64 lb.
Wingspan:	Male:	17-30 inches
	Female:	21-36 inches

APPEARANCE:

Harris hawks are parabuteos which are small to medium, heavy-set birds with long broad wings (like a buteo), long legs, and long narrow tails (similar to the accipiters).

With adult Harris hawks, both sexes are alike in appearance. The legs and feet are orangish-yellow, with the tarsi feathered halfway. Talons are long and powerful. The tail is black with a white base and a white band near the end. Shoulders and thighs are chestnut, and the rest of the bird is dark, except for the bare lores.

Juveniles are lighter in color, with a white underwing and some chestnut. The breast and thighs are streaked with a brownish color. Shoulders are rusty, and they have a white patch at the base of the tail. The tail is sometimes narrowly barred, and is white-tipped. The face and throat are white streaked.

RANGE/DISTRIBUTION:

The Harris hawk is a resident of Southern California, Arizona, New Mexico, and Texas. Their range also extends into Mexico, Central, and South America as far south as Argentina.

HABITAT/TERRITORY SIZE:

Harris hawks are found in the semi-arid areas of the southwest United States and Mexico and prefer scrub with mesquite, cacti, and yucca plants. Depending on the location, the breeding season range can vary from 2.5 to 5 square kilometers, with some overlap of territory between birds.

MIGRATION:

In the fall, large flocks of Harris hawks gather at the extreme northern and southern parts of the range where they may migrate short distances in winter, depending on the weather.

DIET:

Harris hawks are a versatile predatory whose diet is comprised of a large number of rabbits, small mammals, quail, other birds, reptiles, and insects. Some sources note that carrion are eaten by the Harris hawk at times.

HUNTING METHOD:

Harris hawks are a versatile predatory whose diet is comprised of a large number of rabbits, small mammals, quail, other birds, reptiles, and insects. Some sources note that carrion are eaten by the Harris hawk at times.

BREEDING INFORMATION:

Courtship flights have been observed, where the male dove down 150-200 meters onto the back of a female located on a cactus. Interestingly, Harris hawks are polyandrous birds, which means that one female will sometimes have more than one mate. Often, they will form a trio, with two males breeding with the female. The female and her mates all take care of the young.

Nests are found in cacti or trees, with nest height varying from 8-30 feet above the ground. It is made of sticks, twigs, mesquite, and yucca. The breeding season is long, from February to June, during which up to two or even three broods can be hatched. The eggs, of which 2 to 4 are laid, are short and subeliptical, smooth but not glossy, and white or bluish white. Both males and females will help to incubate the eggs, which lasts for about 35 days. Often, other birds will assist in raising the young, from juveniles recently fledged to other adults.They are well feathered and begin to feed themselves by 17 days. Fledging time is about 40-45 days, and the young remain the nest area for 2-3 months after hatching. If the young are threatened, the cry of the adults will become a long and snarling “karr”.

BEHAVIOR:

Other than their pack-like hunting behavior, the Harris hawk is a very gregarious bird and will be in groups not only for hunting but also for breeding. In addition, a behavior called stacking, where several birds will stand on top of another while the bottom bird is perched on a cactus, is another important social behavior. By doing this, the vantage point of the highest Harris hawk allows it to see prey over a greater range and to spot other potential predators.

Described as having a dual personality, Harris’ hawks combine the characteristic modes of hunting and flight of the buteo and accipiters. In scrub country it may be seen perched in a low tree; dashing through thorny bushes in search of prey; or, in the early morning, circling on thermals high above. Usually perches low, on the ground, or in cactus. Their most common call is a loud hiss or growling sound.

STATUS:

Harris hawks are rare birds in certain parts of their range. The population of Harris hawks had decreased dramatically in California because the damming of the Colorado River hurt their nesting sites along the lower parts of the river, and because the cutting of the riparian woods eliminated nesting in the favored sites of the Imperial Valley. By the 1950’s they were nearly gone from California, but in 1979 the Santa Cruz Predatory Bird Research Group made a major effort to reintroduce Harris hawks into California. Their only real predators are coyotes and bobcats who will pull down any nests they can reach.

BIBLIOGRAPHY:

• “Birds of North America”, edited by the National Geographic Society.

• “Birds of North America”, written by Kobbins Brown Zin Singer. 1966.

• “Field Guide to Nest Eggs and Nestlings of North American Birds”, written by Harrison. 1978.

• “The Birder’s Handbook”, written by Ehrlich, Dobkin, and Wheye. 1988.

• “Bird Conservation One”, edited by Temple. 1983.

• “Animal Life Encyclopedia”, by Dr. Bernhard Grzimek, 1972, p. 371.

• “The Audubon Society Encyclopedia of North American Birds”, by John Terres, 1980, p. 482.

• “Birds of Prey of the World”, by Mary Louise Crossman and John Hamlet, 1964, pp. 280-281.

• “A Field Guide to Western Birds”, by Roger Peterson, 1990, pp. 178 and 190.

• “Hawks, Eagles, and Falcons of North America”, by Paul A. Johnsgard, 1990, pp. 190-196.

• Cathi Wright, Oregon Zoo, Assistant Animal Show Coordinator
  Also, material from the Saturday Academy Birds of Prey class was used
  (Instructor: Deanna Sawtelle).