Golden Eagle, Aquila chrysaetos

Golden Eagle

Golden Eagle, Austria, © Henning Werth

Names

English: Golden Eagle
Scientific: Aquila chrysaetos
German: Steinadler
Spanish: Águila real
French: Aigle royal

Taxonomy and Subspecies

Either 6 subspecies [Watson 1997], or 5 [Bauer et al. 2005] recognized. In Europe there are two subspecies. A.c. chrysaetos in most of Europe eastwards to western Siberia. A.c. homeyeri occurs on the Iberian Peninsula, some islands in the Mediterranean, North Africa, Middle East, Caucasus and Iran. [Watson 1997].

Size

Length: 80-93 cm
Wingspan: 190-230 cm
Weight: Males 2,870-4,550 g, Females 3,750-6,660 g

Maximum Age

38 years in the wild, 57 years in captivity. [Mebs & Schmidt 2006]

Habitat

In Europe the Golden Eagle lives mostly in remote mountainous areas, in northern Europe also on lower ground [Forsman 1999]. In some areas, like Scotland the species also lives at the coast, for example on Mull or Skye. The Golden Eagle needs large territories with enough prey and places free of human disturbance where it can build it's nest. It prefers open country or forests with a lot of open spaces where it can hunt. For nest construction, either large trees or cliffs are needed.

Distribution

The Golden Eagle has one of the largest distributions of all eagles. It occurs over most of western North America from Alaska down to Mexico. In the Old World, it occurs from western Europe eastwards to Japan. In Europe Golden Eagles live in Scandinavia, northern Britain, parts of eastern Europe, south-east Europe, Turkey, the Alps, Italy and the Iberian Peninsula.
It is absent from densely populated areas like most of Germany (except the Alps) and most of France, Poland, England, Wales, Hungary, and the Czech Republic. [Mebs & Schmidt 2006]
It was also was extirpated from Ireland, where a reintroduction program is currently underway (see below under Conservation).

Migration

Adult birds mostly sedentary, except in the very north. Juveniles disperse more widely, often serveral hundred kilometers, in some cases more than 2,000 kilometers. [Mebs & Schmidt 2006]

Breeding and Reproduction

Golden Eagles first breed after they are 4 or 5 years old. The nest is build on cliffs or large trees. Normally two eggs are laid, rarely one or three. After hatching, the younger eagle is often killed by it's older sibling. Two chicks are raised only in about every fourth successful brood. This is more often, than in Lesser Spotted Eagles, but less often than in other large eagles like White-tailed Eagles or Eastern Imperial Eagles [Mebs & Schmidt 2006].
In very rare cases, three young fledge (with examples from Scotland, Sweden and Switzerland).

Food and hunting

Feeds mostly on medium sized mammals and birds. Important mammal species are the Alpine Marmot Marmota marmota (in the Alps), Hares, Rabbits, Foxes (incl. adult foxes). The young of Chamois Rupicapra rupicapra, Roe Deer Capreolus capreolus or Alpine Ibex Capra ibex, are taken regularly during the spring.
The Golden Eagle is also capable of killing adult Chamois . It will push them over the edge of a cliff which often kills the Chamois. Such prey is too heavy for the eagle to lift as a whole.
Important birds species are Willow Grouse Lagopus lagopus, Ptarmigan Lagopus muta, Black Grouse Tetrao tetrix, seabirds (at the coast), raptors like Common Buzzards and others. In Spain, the Red-legged Partridge Alectoris rufa is often taken.
Locally, other important prey are turtles (on the Balkans) or West European Hedgehog Erinaceus europaeus (on Gotland in Sweden). [Mebs & Schmidt 2006] Carrion also is an important food source, especially for juvenile and immature birds and during winter.

Population

The biggest populations in Europe are in the Alps, Scotland, Scandinavia and Spain. The population in the Alps is around 1,200 breeding pairs and seems to be stable. In Bavaria, the breeding success was quite low during the last decades and the population of about 50 pairs has been stable mostly because of eagles from Austria or Switzerland moving to Bavaria. In recent years, the breeding success has improved in some areas in Bavaria due to conservation programs (for example by trying to reduce disturbance at the nest sites). The British population, which lives almost entirely in Scotland is about 442 according to the RSPB [RSPB 2008]. In Scandinavia there are about 1,700 - 2,000 pairs [Mebs & Schmidt 2006]. In Spain, there are about 1,440 pairs [SEO 2007]

Threats

Persecution has caused serious a decline of Golden Eagles in many parts of their range and restricted their distribution to remote areas. Today Golden Eagles are legally protected in most countries and persecution has declined dramatically over much of the eagle's range, for example in the Alps.
But in some countries (for example Scotland, southern Europe), illegal persecution through shooting or poisoning is still a major problem. Poisoning is sometimes directed at the eagles themselves, sometimes at mammals like wolves or foxes. In Scotland, poisoning intensity is greatest on land managed for grouse hunting [Watson 1997]. In the eastern Highlands, many suitable territories remain unoccupied. This is thought to be caused by persecution [SRSG 2008]. Sometimes, nests are deliberately destroyed by game managers [Watson 1997].
There is similar persecution in England and this has so far prevented the Golden Eagle from recolonising England in significant numbers. According to the RSPB, there is a continuing threat from egg collectors in some areas [RSBP 2008].
In Spain illegal shooting and poisoning remains one of the most serious threats to Golden Eagles. In Castilla y León, about 2% of the Golden Eagle population is killed through shooting and about 3% of the nests are either robbed or destroyed [SEO 2007]. The use of poison has also increased in Spain. Golden Eagles often feed on carrion (especially the young and during the winter) and so are easy targets for illegal poisoning.

Conservation

For the Golden Eagles, various measures must be taken to secure populations and help them increase where possible:

Persecution through shooting and illegal poisoning must be reduced dramatically where it's a problem. That can be achieved through public education and better law enforcement.
Wind farms should only be built after a detailed environmental study on the effects of the wind farm on the eagles. Those studies most not only be done in breeding areas, but also in locations that are visited during migration, especially where many eagles concentrate during migration. The dispersal of juvenile Golden Eagles should be studied in more detail in many areas so that also can be taken into account before wind farms are built.
The death of Golden Eagles through electrocution could be reduced to zero if all power lines were modified and made bird safe. In some Countries (for example Germany) there are now laws that require power lines to be made bird safe in the future (in Germany, until 2012). But power lines should be secured all over Europe. That would not only benefit Golden Eagles, but also most other raptor species and other birds like owls or storks.
Human disturbance must be reduced to a minimum, especially close to the nests, but also in important hunting areas. For this to be effective, a close monitoring of eagle territories is essential. Only then can disturbance by humans (helicopter flights, climbing, hang gliding, hiking) be reduced effectively.

Status IUCN/BirdLife

Least Concern

Status Global Raptor Information Network

Lower risk

Interviews about the Golden Eagle

Interview with Mike McGrady about Golden Eagles in Scotland

References

[Bauer et al. 2005] Bauer, H.-G., Bezzel, E. & Fiedler, W. 2005. Das Kompendium der Vögel Mitteleuropas. Aula-Verlag

[Forsman 1999] Forsman, Dick (1999). The Raptors of Europe and the Middle East. A Handbook of Field Identification. Poyser, London

[GRIN 2008] Global Raptor Information Network. 2008. Species account: Golden Eagle Aquila chrysaetos. Downloaded from http://www.globalraptors.org on 11 Jun. 2008

[Mebs & Schmidt 2006] Mebs, Theodor & Schmidt, Daniel (2006). Die Greifvögel Europas, Nordafrikas und Vorderasiens. Kosmos Verlag, Stuttgard.

[RSPB 2008] RSPB bird guide account: Golden Eagle. Downloaded from http://www.rspb.org.uk/wildlife/birdguide/name/g/goldeneagle/index.asp on 13 Jun. 2008

[SEO 2007] SEO/BirdLife Spain, Juan M. Vaerla Simó 2007. Aves Amenazadas de España, Lynx Edicions.

[SRSG 2008] THE GOLDEN EAGLE - Downloaed from http://www.scottishraptorgroups.org/raptors/golden_eagle.php on 16. Jun 2008

[Watson 1997] Watson, Jeff (1997). The Golden Eagle. Poyser, London

Books

Forsman, Dick (1999). The Raptors of Europe and the Middle East. A Handbook of Field Identification. Poyser

Mebs, Theodor & Schmidt, Daniel (2006). Die Greifvögel Europas, Nordafrikas und Vorderasiens. Kosmos Verlag.

Preston, Charles R. & Leppart, Gary (2004). Golden Eagle: Sovereign of the Skies. Graphic Arts Center Publishing Company

Watson, Jeff (1997). The Golden Eagle. Poyser

Websites

Golden Eagle - BirdLife Species Factsheet

Global Raptor Information Network species account for the Golden Eagle

Golden Eagle Trust - Reintroduction Program in Ireland

Golden Eagle information by the RSPB

steinadlerschutz.de - Golden Eagle conservation in Allgäu/Bavaria

Roy Dennis, Highland Foundation for Wildlife Golden Eagle species description by the Scottish Raptor Study Groups