This weeks Bird of the Week is the majestic Golden Eagle, one of the most powerful birds in the world.

Description

The Golden Eagle is a huge and powerful bird. Males have a wingspan of about 200cm, females up to 230cm. Their weight is normally between 4 and 6 kilograms, with some females reaching up to 7 kilograms. Their size is normally between 75 and 95cm. In nature, Golden Eagles can reach an age of over 30 years. In captivity some have reached more than 45 years.

Distribution

The Golden Eagle has the widest distribution of all the eagles in the Genus Aquila. It is the only Aquila eagle that occurs in North America. There it can be found in most of the western part of the continent from Alaska down to northern Mexico. In the Old World, it is distributed from Spain, Scotland and Scandinavia eastwards to Japan. The distribution in Europe is scattered and the Golden Eagle is gone from many areas where it historically occurred. The species now lives mostly in remote areas, often in mountains. In central Europa, it occurs only in the Alps. The Golden Eagle is not bound to mountains, though. They can also live in lowland areas when there is sufficient food, no disturbance during the breeding season and no persecution. It now breeds again in lowland areas in Switzerland, Denmark or Sweden.

Breeding

Golden Eagles normally do not breed before reaching the age of at least 4 years. Once paired, partners normally stay together for life.
Golden Eagles lay two eggs (rarely one and very rarely three). The first chick hatches 3-5 days before the second one. Because of this the first chick is considerable stronger than the second one and often kills it’s smaller sibling. This is a behavior that is common among many Aquila eagles. In some species, like the Lesser and Greater Spotted Eagle, almost always only one chick fledges. Golden Eagles raise two chicks more often. It is not yet 100% clear what favors the raising of two chicks. Sufficient food is definitely important. Maybe it’s also helpful if the second chick is a female and the first a male. Female eagles are bigger and stronger than males, so maybe when the second is a female (and the first a male), it can reach the size and strength of the first born after some time in the nest. There are some cases where Golden Eagles raised three chicks successfully. But this is a very rare exception.

Food

Golden Eagles are powerful hunters and are capable of killing large prey like Black Grouse, Red Foxes and small deer species. Normally they feed on middle sized mammals like marmots, rabbits or Prairie dogs (depending on location). They also hunt birds like Ptarmigan. Occasionally they kill crows, Ravens or even raptors like the Common Buzzard. In Denmark, Golden Eagles killed young Cormorants in the nest and there are also reports of Golden Eagles killing adult Cormorants in the air. A very interesting hunting method is used on the Balkan, where the eagles dropped turtles from up to 60 meters above the ground in order to break their shells.

Conservation

The Golden Eagle is not globally threatened. That does not mean that the species is safe everywhere. In many countries the population is low and restricted to remote areas (like in Germany, France or many parts of the USA). Golden Eagles are still illegally persecuted in some countries, for example in Scotland. Some hunters there see them as a competition because the eagle feed on Scottish Grouse, which is a very popular game bird. In Scotland, as in other countries, the Golden Eagles are sometimes shot or poisoned. There are many places in Scotland that would be suitable Golden Eagle habitat, but where none breed. Some conservationists think this is due to persecution.
In order to protect Golden Eagles, illegal persecution must be stopped. Current populations must be fully protected if not already done so. The use of pesticides should be reduced. Wind farms should not be build close to breeding or hunting territories or on migration routes. Disturbance around nests must be kept at a minimum, for example climbing must not be permitted there during the courtship and breeding season.
The current population in the Western Palearctic is around 10.000 breeding pairs, with Spain, Scandinavia, Turkey and the Alps being the strongholds.

For more information about Golden Eagles:
Golden Eagle page at globalraptors.org
Golden Eagle Trust in Ireland