What Do Golden Eagles Eat? Prey and How They Catch It

The core of the golden eagle diet

Studies of prey remains at nests across North America and Eurasia show the same pattern. Most of the food, by weight, comes from mammals weighing roughly 0.5–5 kg (1–11 lb). Those are animals big enough to be worth the effort, yet small enough to subdue and, often, to carry. The main groups are:

• Hares and rabbits: jackrabbits and cottontails in North America; mountain hares, European hares and European rabbits in Europe.
• Ground squirrels and marmots: ground squirrels and prairie dogs on western American grasslands; alpine marmots in the Alps; and marmots and susliks on the steppes of Asia.
• Gamebirds: grouse, ptarmigan, partridges and pheasants.
• Other prey: foxes, young hoofed mammals, crows, waterbirds, other birds of prey, reptiles and, rarely, fish.

The golden eagle is largely an opportunist within this list. When rabbits crash because of disease, or a hare population falls, it switches to whatever is available, and breeding success often drops in those years.

What golden eagles eat in different regions

Regional diets show how flexible the species is.

In southwestern Idaho, where jackrabbits are very common, eagle territories can be tiny, and breeding success rises and falls with the jackrabbit cycle. In the Alps, the marmot is so important that eagle pairs often hunt the same alpine meadows every summer. Our guide to the animals of the Alps shows how eagles fit into that mountain food web.

In Scotland, the diet changes with the land. On grouse moors in the east, red grouse and hares dominate; on the wet, poor western uplands, live prey is scarce and eagles rely much more on deer and sheep carcasses.

How golden eagles hunt

Golden eagles hunt by day, mostly in the morning and late afternoon. They spend long periods perched on a lookout or soaring high over open country, using their exceptional eyesight to spot movement on the ground. Researchers have described several hunting methods, used according to the prey:

1. High soar and stoop. The eagle spots prey from high up, folds its wings and dives steeply, leveling out at the last moment to strike.
2. Contour flight. It flies fast and low along a slope or ridge, using the land as cover, and surprises animals feeding in the open. This is a favorite method for ground squirrels and marmots.
3. Tail chase. A running hare or flying grouse is followed closely until the eagle can grab it.
4. Pair hunting. Mated pairs sometimes hunt together, one bird flushing or distracting prey while the other attacks.

The eagle kills with its feet. It grips with all four toes and drives in the long hind claw, which can be 4.5–6.3 cm (1.8–2.5 in) long, and then holds on until the prey stops moving. Hunting is far from easy: in one Idaho study, about one in five attempts succeeded.

Carrion and winter feeding

Golden eagles readily eat animals that are already dead. In winter, when ground squirrels and marmots are hibernating and hares are hard to find in the snow, carcasses of deer, sheep, elk and other large animals can make up much of the diet in many areas. Eagles often gather at large carcasses and may squabble over them.

This habit carries risks. Eagles feeding on shot animals or gut piles may swallow fragments of lead ammunition, and those eating roadkill are often hit by vehicles. Carrion feeding has also given eagles a poor reputation among some farmers, because an eagle seen at a dead lamb is often blamed for killing it.

Large prey and unusual meals

Golden eagles are powerful enough to attack animals several times their own weight, although they do so rarely. Recorded examples include deer fawns, chamois and ibex kids, young pronghorn, foxes and, occasionally, adult deer weakened by winter. Large prey is eaten on the spot, sometimes over several days, because an eagle can only carry a fraction of such weight. How much an eagle can lift is explained in How much weight can an eagle carry?.

In dry Mediterranean and Middle Eastern areas, golden eagles have been recorded carrying tortoises up and dropping them onto rocks to break the shell. They also kill other birds of prey, including owls and buzzards, and have been seen taking large birds such as geese and cranes.

How much and how often golden eagles eat

An adult golden eagle needs, on average, about 230–250 g (8–9 oz) of food a day, roughly the weight of a small ground squirrel. In reality, meals are irregular. Eagles can go up to a week without food and then gorge on up to about 900 g (2 lb) at once, storing it in the crop, a pouch in the throat, before digesting it slowly.

During the nesting season the male does most of the hunting at first, bringing prey to the female and chicks. Once the young are a few weeks old, both parents hunt, and a pair with a chick may need to catch prey almost every day.