Harris’s Hawk

Quick Take

• Harris's hawks hunt like wolves, a behavior that gives them access to prey most raptors can't touch alone. See cooperative hunting →
• The group has a strict social hierarchy, but the alpha female breaks her own rules in a surprising way. Explore the social hierarchy →
• The very structure Harris's hawks depend on for nesting also quietly kills a surprising number of them every year. Electrocution and nesting risks →
• In the wild this hawk lives a fraction of the lifespan it's capable of, and the gap is bigger than you'd expect. Wild vs. captive lifespan →

Also called the bay-winged hawk, the Harris’s hawk is one of the few species of raptors known to go hunting in ‘packs,’ a group that includes birds such as the Aplomado Falcon. This behavior is thought to be one of the adaptations that help the bird to successfully capture prey. It also allows them to catch prey larger than a single bird could handle. One way to identify the Harris’s hawk is to observe a group hunting together — few other birds of prey show such behavior.

Where To Find the Harris’s Hawk

The Harris’s hawk’s range is in the southwestern United States, down to Mexico, Central America, and the drier habitats of South America. It lives in semi-arid or desert areas that feature such plants as cacti, palo verde, mesquite, and cottonwoods. They can sometimes be seen in cities and suburbs. Because it is used in falconry, there are also Harris’s hawks in Europe.

Nests

The hawk builds its nest in trees such as mesquite or paloverde, saguaro cacti, and even utility poles, typically at a height of 12–25 feet above ground. It is made of weeds, twigs, and sticks and lined with softer plant materials.

Classification and Scientific Name

The Harris’s hawk’s scientific name is Parabuteo unicinctus. Parabuteo comes from the Greek word para, which means “like,” and the Latin word buteo, which means a type of buzzard. Uni is from the Latin unus, which means “one,” and cinctus means “girdled” and describes the tail. So Parabuteo unicinctus can be translated as a buzzard-like bird with one band around its tail. As for the “Harris’s” part, the hawk was named after Edward Harris, a supporter of the naturalist John James Audubon. The hawk has two subspecies:

• P. u. harrisi
• P. u. unicinctus

Appearance

The hawk’s coloration makes identification somewhat easy. It is considered to be large for a hawk, with a length of 18 to around 23 inches and a wingspan of about 40.5 to 47 inches. It has a hooked bill and ferocious talons, adaptations for catching and killing its prey. It is slimmer than most other hawks, and its coloration makes it especially beautiful for a raptor. It has a chestnut patch on its shoulders, and the feathers on its thighs are also chestnut. The rest of the body is brown, and the tail is long and black, with a white band at the base and white at the tip. These white bands are key to identifying this hawk. The cere is yellow, as are the long legs. Females are larger than males and weigh 1.8 to 2.6 pounds compared to the males’ 1.2 to 1.8 pounds. The coloration of juveniles is a little duller than that of adults.

The hearing and vision of these birds of prey are acute, and they also produce a repertoire of rather harsh vocalizations to communicate with each other.

Behavior

These hawks are active during the day and form social units, usually two males and a dominant female. If there’s more than one female in the group, the dominant female is the only one allowed to breed. Even so, the beta female is still higher in rank than all the other males. Birds lower down in the hierarchy are most often juveniles and may even be the offspring of the dominant pair. Adults and juveniles go hunting, defend their territory, and protect the nest together.

The members of a hunting party have different roles when it comes to catching prey. Like other hawks, they fly in circles until they spot prey. Then, the group lands and tries to flush the animal out of its hiding hole. When it finally emerges, another hawk chases after it. These hawks can run after prey at surprising speeds. Finally, a hawk grabs the prey and mantles it — that is, covers it with its wings. The birds all share in the kill. Sometimes they’ll scavenge if there’s no live prey about. Found in relatively warm climates with lots of food, the birds do not migrate.

Diet

The diet of the bay-winged hawk includes mice, rats, reptiles, other birds such as herons, wrens, and mockingbirds, insects, wild rabbits, and hares. They’ll eat carrion if there’s nothing else available at the moment. They will also take chickens and pet rabbits. In falconry, the hawk is used to keep down the population of pigeons in urban areas.

Predators and Threats

As birds of prey, Harris’s hawks have few predators. Building nests high in a tree or cactus helps to protect the young, but they are still subject to predation by ravens, eagles, red-tailed hawks, great horned owls, and coyotes. Another benefit of living in social units is that other hawks can watch for predators and sound an alarm call if one is seen. Then, a group can chase off a predator, such as a raven, while the alpha female stays at the nest.

Habitat destruction poses some threat to the hawk, though they appear to have adapted. However, trying to land on electrical transformers kills a surprising number of these birds every year.

Reproduction, Babies, and Lifespan

Only the alpha female is allowed to breed, and she is supposed to breed only with the alpha male, though females often mate with more than one male. This is one of the adaptations to living in a place where prey is abundant and males outnumber females. The group helps build the nest, and the female takes the lead on incubating the eggs, with incubation lasting around 33 to 36 days. Both males and females feed the chicks.

Female Harris’s hawks can breed throughout the year. They usually have up to three clutches a year with between one and four eggs per clutch. The chicks start to fledge when they’re between 35 and 45 days old and are independent when they’re two to three months old. In the wild, the Harris’s hawk lives 10 to 12 years but can have a lifespan of 20 to 25 years in captivity.

Population

The Harris’s hawk’s population is believed to be between 30,000 and 87,000, though there are areas where its population is declining. Despite this, its conservation status is Least Concern.