In coloring, the adult harrier hawk is primarily gray. It has narrow bands of white and black on its belly and thighs. Its tail and the tips of its wings are black. The flesh around its beak is bare and yellow, but this turns red if the bird becomes excited. The hawk also has a large ruff of feathers around its face, giving it a crested appearance.
The harrier hawk has several physical attributes which make it different from other raptors. It has long, jointed legs, somewhat like a crane's. The leg joints have the capacity to bend back, forward, and sideways. In addition, the hawk has a long and very thin beak. These attributes help it hunt for food in hard-to-reach places.
Harriers are omnivorous, meaning they eat a wide range of foods. They use their jointed legs to climb along the branches of trees, using their wings for balance, and poke their long beaks into holes and cracks for larvae. They'll raid the nests of other birds for fledgelings and will hunt down rodents and other small mammals. In addition to this, they can eat the fruit of the oil palm tree.
As part of their mating ritual, harrier hawks will circle around each other in midair. Sometimes the male and the female will meet in midair and touch claws. This circular courtship pattern gives the hawks their genus name, Circus.
Harrier hawks prefer to nest in trees near water. They will construct a nest in the fork of a tree, in which they lay one to three eggs. They will also construct nests on cliff ledges. The nest is always lined with soft, green twigs.
On average, harrier hawk eggs are incubated for 35 days. When they hatch, the young hawks are extremely competitive. Before they can fly, the stronger fledgelings will push their rivals out of the nest. Even though a harrier hawk can lay as many as three eggs, usually only one hawk will survive to be raised to adulthood.
Unlike many African species, the harrier hawk is not considered endangered. Its population remains stable even though its habitat ranges over most of Africa and it often comes in contact with humans.