California Raptor Center

Harris Hawk

Scientific Name: Parabuteo unicintus (Parabuteo is Greek for ‘beside or near”, hence, ‘similar to buteo”. Unicinctus in Latin from uni ‘once’ and cinctus ‘girdled’ a reference to the white band at the base of the tail. This bird is also called the Bay-winged Hawk).

Size: Length: 18-23in  Wingspan: 40-47in

Weight: Female: 918-1203g (~2.0-3.4lb) - Male: 634-877g (~1.4-1.9lb)

Lifespan: In the wild these birds may reach 15 years. In captivity they can reach 25 years or more.

ID: These are medium sized hawks with long tails and broad wings. Adult plumage is uniformly brown with distinct reddish shoulders, upper and underwing coverts, and leg feathers. The tail is dark with white upper and undertail coverts and a white base and terminal band. Juveniles are similar to adults but are less distinctly colored and have a white belly with brown streaking. The tarsal feathers are pale with reddish barring and there is barring on the tail and wings.

Hunting: They commonly hunt in groups, increasing their success rate. These hunting groups consist of a breeding pair and other helpers, with the female dominating. They are fast flyers and once they have spotted their prey, they land and take turns trying to scare and actually flush the prey animal until it darts from beneath its hiding place. Another member of the hunting group captures the animal and assumes a posture known as mantling, in which the hawk shields the prey with its wings to hide it from other birds. It has been suggested that group hunting is encouraged by the dense brush and thorny nature of their habitat. There is some evidence that these hawks may feed on carrion if food availability is low.

Prey: Harris’ eat cottontails and jack rabbits, rats and mice, lizards, and birds.

Breeding: Most often, social groups of Harris' hawks contain a single monogamous breeding pair. However, these hawks are known to practice simultaneous polyandry, where more than one male mates with one female and shares in the responsibilities of raising offspring. Polyandry is commonly found in areas where the habitat quality is rich as opposed to arid habitats where the chances of reproductive success are less, even when there are three adults hunting.Harris' hawks build their nests in saguaros, palo verdes and mesquite trees at an average height of 5 meters. In urban areas, nests can be found on cottonwoods, ironwoods, palm trees and electrical towers. Nests are platforms made of sticks, weeds, twigs, and are usually lined with soft mosses, grasses and roots. Between two and four eggs are laid at a time. Females have the ability to breed all year long and can lay two to three clutches within a year. The incubation period lasts about 35 days and the males often share duties with the female during this period. Fledging occurs after another 40 days. The young birds tend to stay around the nest area for two to three months longer.Both the female and the male contribute to parental care. Harris' hawks practice cooperative breeding, with several birds helping with building nests, incubation, feeding, and defense. This assistance increases nest success. There is often a trio consisting of two males and a female which aid in the nest cycle.

Range: Harris's hawks range in the United States primarily from southern Arizona through New Mexico to central Texas. They have also been reported in California, Nevada, Utah and Oklahoma. Harris's hawks are also found from Central and South America to Chile and northern Patagonia.

Status: Harris's Hawks are not listed as threatened or endangered. They are included in CITES appendix II and they are protected from harassment and illegal shooting by the Migratory Bird Treaty Act.