Northern harrier, sometimes called marsh hawk, is the only species of harrier that lives in North America. It also lives in Europe, where it is called a hen harrier, and in northern and central Asia. A harrier is a type of hawk.
Northern harriers have long wings, tails, and legs. The birds measure 17 to 24 inches (43 to 61 centimeters) long with a wingspread of 40 to 54 inches (101 to 137 centimeters). The females grow slightly larger than the males. Adult male northern harriers are mostly light gray above and white below. Adult females have brown coloring above with dark streaking underneath. The young birds resemble the females but have less streaking below.
Like owls, northern harriers have a saucer-shaped ruff of feathers around the eyes. This ruff, called a facial disk, reflects sound to the harrier’s ear openings. The northern harrier usually hunts small birds and mammals. Its facial disk helps it detect prey by sound. The bird then swoops down and kills its victim.
Northern harriers nest on the ground. The males are the only North American birds of prey that typically mate with more than one female during the same period of time. Females usually lay from four to six eggs.