Golden Eagle

A Fast Dive and a Hunting Partner

The Golden Eagle (Aquila chrysaetos) stands 75 to 90 centimeters tall (2.5 to 3 feet), with a wingspan that stretches 1.9 to 2.3 meters (6.2 to 7.4 feet) tip to tip. San Diego Zoo Wildlife Alliance gives females 3.6 to 6.6 kilograms and males 2.8 to 4.5 kilograms. A wild golden eagle can live up to 38 years, and up to 50 in expert care. It can hit up to 120 miles per hour (193 km/h) in a dive, in play or after prey. Golden eagles often hunt in pairs: one eagle drives the prey toward its waiting partner. The talons, the claws on the feet, kill and carry the prey, and the beak is only for eating.

A Hunter Across the Northern World

This is a Holarctic species, spread across the northern continents. Animal Diversity Web lists it throughout Eurasia, in northern Africa, and in the western half of North America from Alaska down to central Mexico, with small numbers in eastern Canada and scattered pairs in the eastern United States. It lives in open and semi-open country from sea level up to 3,600 meters, including tundra, shrubland, grassland, and coniferous forest, and most golden eagles are found in mountainous areas. Rabbits, hares, ground squirrels, and marmots are the primary diet, rounded out with birds and reptiles, and occasionally a coyote or badger. San Diego Zoo adds that it sometimes takes deer, and it may eat carrion when live prey is scarce.

Riding Ridge Winds on Migration

The migrations of soaring birds are shaped by weather that produces two kinds of uplift: thermal lift from rising warm air, and orographic lift from wind forced upward by the landscape. A GPS-tracking study followed golden eagles and turkey vultures during autumn migration across eastern North America to compare how each species used them.

A different kind of lift Turkey vultures nearly exclusively used thermal lift, while golden eagles primarily used orographic lift, the wind pushed upward as it hits a mountain ridge.

Nests, Siblings and Lead

A golden eagle pair mates for life and builds several nests within its territory over the years, adding material every year so each one gets bigger and bigger. The largest nest on record, according to Animal Diversity Web, measured 6.1 meters tall and 2.59 meters wide. The female usually lays two eggs, three to four days apart, and incubation lasts 41 to 45 days. The chicks hatch several days apart, and the oldest often attacks its younger sibling and sometimes kills it. In the western United States a pair’s breeding-season home range covers 20 to 33 square kilometers, and the pair defends its boundaries with flight displays. Golden eagles have few recorded predators: wolverines and grizzly bears are the only recorded predators of their nestlings. A serious threat is lead from hunting ammunition. A tracking study found that even sublethal lead levels in scavenging golden eagles’ blood can likely harm how high they fly and how fast they move, and lead levels in the livers of dead eagles suggested that such exposure raises the risk of dying.