The gyrfalcon is the largest falcon in the world. A gyrfalcon is somewhat larger than a peregrine falcon. Gyrfalcons live in the far north, in the Arctic. They are top predators in the Arctic.

A gyrfalcon is about 20 to 25 inches long, and its wings spread about four feet from tip to tip. A female is bigger than a male. A male weighs about 800 to 1,350 grams, and a grown female can weigh as much as about 2.1 kilograms (about 4.5 pounds).

Gyrfalcons come in white, gray, and dark forms, called morphs. White gyrfalcons are found mainly in Greenland.

A gyrfalcon often hunts by flying fast and low over the ground. Gyrfalcons eat mostly other birds. Ptarmigan are the gyrfalcon's main food. A gyrfalcon also eats waterfowl and seabirds, and some small mammals, such as ground squirrels and hares.

The scientific name Falco rusticolus means a countryside-dwelling falcon.

In the Middle Ages, only a king could hunt with a gyrfalcon.

Most gyrfalcons stay in the far north all year. In winter some gyrfalcons move south, and some stay in their territories. In winter a few gyrfalcons come south to the northern edge of the United States.

A gyrfalcon does not build its own nest. It nests on cliffs. Sometimes a gyrfalcon lays its eggs on a bare cliff ledge with no nest. Some use an old nest that another bird, such as a raven, built. A gyrfalcon usually lays three or four eggs, and the eggs take about five weeks to hatch. Adult gyrfalcons bring food to the nest for their young.

Words to know

• ptarmigan: a bird
• morphs: color forms
• waterfowl: water birds
• predators: hunters