The Golden Eagle (Aquila chrysaetos) is one of the best known birds of prey in the Northern Hemisphere. Like all eagles, it is part of the family Accipitridae.
There are five noted subspecies of the Golden Eagle:
- Eurasian Golden Eagle (A. c. chrysaetos)
- American Golden Eagle (A. c. canadensis)
- Spanish Golden Eagle (A. c. homeryi)
- Japanese Golden Eagle (A. c. japonica)
- Russian Berkut (A. c. daphanea)
Previously the Golden Eagle lived in temperate Europe, North Asia, North America, North Africa and Japan. In most areas this bird is now a mountain-dweller, but in former centuries it also bred in the plains and the forests.
There has been a great decline throughout Central Europe, and the Golden Eagle is now restricted to the Alps. In Britain, there are about 500 birds left which can be found in the Scottish highlands. In North America the decline has not been as dramatic.
In Central Asia, Golden Eagles are occasionally trained for falconry. In Kazakhstan there are still hunters using these eagles in order to catch deer and antelope.
Efforts are being made to reintroduce the species in Ireland, where they had been extinct since the early 20th Century. 35 birds have been released into the wild since 2001.
Golden Eagles are monogamous for life. They construct several nests (called eyries) within their territory and use them alternately for several years. The nest consists of heavy tree branches which are made softer with grass.
Old eyries may be 2 meters in diameter and 1 meter in height, as the eagles enlarge their nests every year. If the eyrie is situated on a tree, supporting tree branches may break because of the weight of the nest.
The female lays an average of two eggs between the months of January and May (depending on the area). Incubation lasts 45 days. Hatchlings are entirely white and are fed for fifty days before they are able to make their first flight attempts and eat on their own. In most cases only the older chick, which takes most of the food, survives, while the younger one dies before leaving the eyrie.
Adult birds have an average length of 30-34 in (75-85 cm), a wingspan of 70-80 in (175-200 cm), and a weight of 3 to 5 kg. Like all birds of prey the females are slightly larger than the males.
Golden Eagles often have a division of labor while hunting: one partner will drive the prey toward its waiting partner. Their prey includes marmots, hares and mice, and occasionally birds, martens, foxes and young deer. Larger mammals like chamois or adult deer are sometimes taken, but only if they are wounded or sick. In the US, Golden Eagles often take lambs as prey, providing a significant source of mortality and earning the enmity of sheep ranchers.