Common Black Hawk Life History

Habitat

In the United States and northern Mexico, Common Black Hawks inhabit riparian forests in canyons and deserts. They specialize in hunting aquatic prey from perches, usually from tree limbs that overhang the water or from rocks in the streambed. Black hawks seldom hunt around lakeshores, unless there are abundant perches and places with shallow water. Tree species that dominate their favored habitats in Arizona and New Mexico include Fremont cottonwood, Arizona sycamore, willows, velvet ash, Arizona walnut, ponderosa pine, Arizona alder, and Douglas-fir. Farther south, from Mexico through northern South America, black hawks inhabit a much greater variety of wetland habitats in addition to riparian woodlands: mangrove forests, freshwater swamps, marshes, flooded forests, and mountain streams.

Food

Common Black Hawks eat mainly fish, reptiles, small mammals, and invertebrates. They are versatile predators that watch for prey from perches that overhang shallow parts of streams and rivers, then drop onto it. They normally perch in trees or on prominent rocks that afford a good view of a section of water but sometimes search for prey when soaring or even when standing in shallow water. On occasion they “herd” prey into shallower water by walking and waving their wings. Prey includes larval and adult grasshoppers, ants, wasps, centipedes, waterbugs, dobsonflies, moths, butterflies, scarab beetles, bombardier beetles, darkling beetles, and ground beetles. They also eat larger prey such as small clams, crayfish and other crustaceans, fish, frogs (including tadpoles), snakes, lizards, rodents, and rabbits. They occasionally go after small birds and on rare occasions eat carrion. With larger prey, Common Black Hawks often return to a favored perch to remove undesirable parts like fish fins before consuming. If prey is plentiful, they may cache (store) it for later consumption.

Nesting

Nest Placement

Nests are set in crotches or forks in large trees, often a cottonwood, sycamore, or willow, usually along the edge of a river. The height above ground ranges from 30 to 90 feet.

Nest Description

Male and female construct a large, bulky nest of sticks taken from surrounding trees and line it with fresh green leaves.

Nesting Facts

Behavior

Common Black Hawks are socially monogamous, and some pairs studied in Arizona stayed with the same mate in several successive nesting seasons. When pairs return to their breeding territory (a short stretch of river with a nest tree), they immediately begin flight displays over the area. Males start with slow flights, with deep, exaggerated wingbeats. They also soar high, then suddenly dive, pull out of the dive, and hang in the air. Females join their mates in these performances, flying in tandem with the male, calling, dangling their legs, and sometimes flying upside down to lock or touch talons with the male. Both also make swooping passes at their perched mate. These displays maintain the pair bond and warn other black hawks to avoid the territory. Males also feed females as part of courtship, and they bring sticks to the nest with similar ceremony and much vocalizing. When nesting, Common Black Hawks chase most raptors, as well as ravens and vultures, away from the nest area. Their aggressive flight displays directed at intruders look similar to their courtship displays. Perched birds may raise their nape feathers and partly open their wings in warning. They may even strike humans that come too close to the nest. Both adults incubate the eggs and feed and tend the young, but only the female broods the young under her wings. The male’s primary role is to bring food to the nest; the female normally does most of the actual nest defense at this stage. The pair’s aggression toward intruders abates after the young are about two months old. Back to top

Conservation

The Common Black Hawk is rare enough in the United States to be of conservation concern, although it is common across its large range elsewhere in the Americas. Partners in Flight estimates a global breeding population of 2 million individuals and rates the species an 11 out of 20 on the Continental Concern Score, indicating a species of low conservation concern. The historical loss of riparian habitat in the Southwest has slowed, but agricultural practices that lower the water table or divert water resources continue. Livestock grazing can damage regeneration of the habitat. The proliferation of nonnative saltcedar (tamarisk) inhibits growth of native riparian vegetation they favor.

Credits

Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.

Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

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