White-tailed Eagle, Haliaeetus albicilla

White-tailed Eagle

White-tailed Eagle, Germany, June 2009, © Markus Jais

Names

English: White-tailed Eagle, White-tailed Sea Eagle
Scientific: Haliaeetus albicilla
German: Seeadler
Spanish: Pigargo europeo
French: Pygargue à queue blanche

Taxonomy and Subspecies

No subspecies. The population in Greenland is no longer considered a subspecies [GRIN 2009, Mebs & Schmidt 2006]. Closely related to the North American Bald Eagle Haliaeetus leucocephalus. They are sometimes considered to form a superspecies [Bauer et al. 2005].

Size

Length: 77-95 cm
Wingspan: 200-245 cm
Weight: Males 4,100-4,600, Females 5,200 - 6,900g

Largest eagle in Europe. A spectacular sight!

Maximum Age

36 years in the wild, 50 years in captivity. [Mebs & Schmidt 2006]

Habitat

Most of the time, especially during the breeding season, found close to water. But can also be found away from water, for example in agricultural areas when enough is food available.
Found at the coast but also along large rivers and lakes. White-tailed Eagles often build their nest in forests, but sometimes also in small groups of trees, even surrounded by agricultural areas.

Distribution

The most western population is on the west coast of Greenland. A small population lives on the west coast of Iceland. A small (reintroduced), but increasing population lives in Scotland. In Scandinavia mostly along the coast of the North and Baltic Sea. In central Europa the White-tailed Eagle breeds in Denmark, Germany, Austria, Slovakia, Hungary and the Czech Republic. In Germany mostly in the north and east but recently expansion to the south with a now a small population in Bavaria. Austria has been recolonised recently. From Poland on eastwards via the Baltic States, Belarus and Russia eastwards to the Pacific. Patchily distributed in south-east Europa with only small populations in most countries.
The White-tailed Eagle has increased it's distribution in the last 40 years after a - sometimes huge - population increase in Scandinavia, north-eastern and central Europa. In 2006 a pair started breeding successfully in The Netherlands.

Migration

Adults of central Europa mostly sedentary [Mebs & Schmit 2006]. Birds from northern Russia and northern Asia mostly migratory [Bauer et al. 2005].
Northern birds may spend the winter in central Europa, for example in Austria along the Danube or along the March river (border between Austria and Slowakia).
Juveniles and immature birds move around more.

Breeding and Reproduction

Nests are built on trees or (along the coast) also on cliffs. White-tailed Eagles nests can become very large, especially when the eagles (often several generations of eagles) at to the nest every year.
The large eagles prefer old and big trees, especially European Beech and Scots Pine. But sometimes much smaller and more instable trees are chosen if no other options are available. In northern Germany there is a nest close to the Wadden Sea in a young poplar plantation. When the eagles built their nest there for the first time, the trees were only around 30 years old. Still, the pair has raised young successfully over several years since their first breeding attempt.
White-tailed Eagles normally start breeding with about 4 or 5 years but in rare cases, even 3 year old birds have nested successfully.
1-3 (normally 2) eggs are laid. Incubation time is about 38 days and the young stay in the nest for about 80-90 days [Mebs & Schmidt 2006].
Like in most raptors, after hatching, the female feeds the young and protects them against predators and weather. The male does most of the hunting. The female will help hunting when the chicks are about 4 weeks old [Mebs & Schmidt 2006].
Normally either one or two chicks fledge. Normally about 50% of the successful pairs raise two chicks, the rest only one. Three chicks are rare [Mebs & Schmidt 2006].

Food and hunting

The White-tailed Eagle has a very varied diet. It feeds on fish, birds and mammals. The percentage of each of this groups varies during the year and also from place to place. The White-tailed Eagle is an opportunist. It will use the food source that is most easily available. During the breeding season, fish is often the most important source of food followed by birds. But this can vary depending on local food supply. Especially during winter, carrion is an important food source. In a study done in northern Germany [Nadjafzadeh & Krone 2008], fish were the most important food source all year around. But it's percentage varied. In April fish made up almost 90% of all food, while in December it was below 50%. Birds were the 2nd most important food source except for November when mammals were as common as birds. In December, mammals were even more important than birds. Let's look a little closer at the different food sources:

Birds

The White-tailed Eagle hunts mostly water birds like ducks, geese, grebes or coots. But it is quite flexible here. It can also hunt birds away from water, for example Pheasants. Even large birds like Black and White storks or Common Cranes are sometimes killed.
At the coast, White-tailed Eagles make use of the large seabird colonies, often killing young birds.

White-tailed Eagles are known to kill nestlings of other birds, for example of Common Buzzards, White Storks or Great Cormorants. Especially a Great Cormorant colony can become a valuable source of food. The cormorants don't defend their nests as aggressively as other birds like gulls. When a White-tailed Eagle arrives, they mostly panic and leave the nest. It is then easy for the large eagle to kill the young cormorants in the nest. This can have a dramatic effect on the cormorants and their breeding success. Beside the young cormorants killed by the eagles, many eggs get destroyed and young probably die when the adult cormorants leave the nest in panic. In Schleswig Holstein (northern Germany), whole colonies have moved because of heavy predation by White-tailed Eagles. [Kieckbusch & Koop 2008]

Fish

Fish are in many areas the most important prey, especially during the breeding season.

Mammals

Mammals are often taken as carrion, especially during winter when many mammals die because of the cold weather and low food supply. In eastern Germany, White-tailed Eagles have been observed to feed at wolf kills.
The White-tailed Eagle is also capable of hunting mammals itself. Popular are susliks, rabbits, different species of hares or muskrats. White-tailed Eagle on Greenland also kill Arctic Fox, especially the pups.
[Fischer 1984] mentions attacks on Roe Deer. This were old and/or week animals. The White-tailed Eagle was observed to grab the Roe Deer at the back and was carried 20 meter and 60 meter in another case. In one case, three eagles were later observed feeding on the dead deer. But killing Roe Deer is a very rare and exceptional occurrence. A healthy Roe Deer is not among the White-tailed Eagle's regular prey.
Other mammals being killed mentioned in [Fischer 1984] are young seals (up to 10 kg), European Otter, young wild boar and domestic cats.

White-tailed Eagles either hunt from a perch or from flight while searching for suitable prey. Good divers like cormorants, grebes or even divers (loons) are hard to catch, at least when they aren't sick or injured. Those birds are often hunted together by two birds, usually a pair, but also adults together with young birds [Fischer 1984].

Population

The population of the White-tailed Eagle in Europa has increased dramatically during the last 30 years. [Mebs & Schmidt 2006] give a number of around 6000 pairs for Europe. The numbers are probably already higher now. For example, for Germany [Mebs & Schmidt 2006] give a number of 470 pairs (a spectacular increase from only about 110 pairs in Germany in the 1960s) for the year 2004. In 2008, the population was already around 600 pairs.
Another example is the population in countries along the Danube river. For this area, [Mebs & Schmidt 2006] give a population between 315 and 405 pairs. According to [Probst et al. 2009], the population in this area was already between 559 and 611 pairs, although a better knowledge of the population may also have lead to a higher number of pairs. But the population has definitely increased in those countries.
Here are the detailed numbers for the countries along the Danube River according to [Probst et al. 2009] in the years 2005-2008:

Country Population in pairs
Bavaria and Baden-Würtemberg (Germany)6
Austria7-10
Czech Republic60
Slovakia 4-8
Hungary 204-210
Slovenia 7-11
Croatia 150
Bosnia and Herzegovina 5
Serbia 70-100
Montenegro 0
Romania 30
Bulgaria 10-15
Ukraine (along the Danube) 6

The country with the largest populations in Europe are Norway with about 2.000 pairs in 2003 (probably higher today), the European part of Russia with 1,000-2,000 pairs and Poland with 660 pairs in 2004. In Sweden there are about 350 pairs and in Finland 250 [Mebs & Schmidt 2006].
The reintroduced population in Scotland has reached 46 territories in 2009.

Threats

Despite the population increase during the last 30 years, the White-tailed Eagle still faces many threats. Natural causes of death can be diseases or predation of the young, for example by crows. The most common natural cause of death are territorial fights with other White-tailed Eagles.
But many eagles die because of human-caused problems. Some birds are still shot which is a shame in the 21st century. But at the moment, the numbers of birds shots appears to be low and other human-caused problems are much more severe.

In Germany, by far the highest number of birds die because of lead poisoning, followed by collisions with trains, trauma (violent impact which could not be further determined), suspected illegal poisoning, electrocution, collision with wind mills, collision with power lines, confirmed poisoning, collision with cars, shot birds and mercury poisoning [Krone et al. 2009].
Collision with trains is quite common in Germany. This happens when animals like Roe Deer get killed by trains and are not removed from the rails. The eagles find the carrion and feed on it. When a fast train (ICE trains in Germany can reach 300 km/h) approaches, the eagles often can not take off fast enough or when they can, they can get caught in the suction caused by the train.
That illegal poisoning still occurs is very sad. The real number of poisoned birds is probably much higher as not all birds are found. In at least 10 cases, the poisoning could be verified as the cause of death in Germany, in another 19 cases, illegal poisoning was suspected [Krone et al. 2009]. In Hungary, between 1998 and 2008, at leat 28 White-tailed Eagles were poisoned [Horváth 2009].
Electrocution and collision with power lines is another important cause of death for White-tailed Eagles, as there are still many power lines in areas where the eagles occur, that are not safe for birds. The huge White-tailed Eagle with a wingspan up to 245 cm can easily touch a power line while taking off from a pylon (or while landing). The birds also can touch two lines at the same time, causing a short circuit which normally kills the bird.
The most important cause of death in Germany is lead poisoning [Krone et al. 2009], which happens when the Sea Eagles eat carrion of deer, boars or waterfowl, that was shot with lead ammunition. Not all shot animals die immediately after shooting and when then escape the hunters, they die later somewhere else and are then eaten by carrion eating birds like White-tailed Eagles. Often, the hunters leave parts of the shot animals (the guts) in the field. When they contain lead, this can cause the death of eagles when they feed on the remaining guts.
The increasing number of wind farms has also caused some death in recent years. A study in Germany found 15 dead White-tailed Eagles as victims of windmills (the only raptors with more victims where Red Kites and Common Buzzards) [Dürr & Langgemach 2006].

Conservation

The conservation of this magnificent bird must address all the threats mentioned above.
Electrocution should be a problem of the past and all power lines should either be put in the ground or make secure for all birds.
Wind farms should not be placed close to current nests, frequently visited feeding areas and other places where many individuals might concentrate. Possible future breeding territories due to range expansion (e.g. in Bavaria, Belgium or France) should also be kept free from wind turbines and other potential threats like dangerous power lines.
Lead ammunition must be banned across Europe not only for White-tailed Eagles but also for the conservation of many other raptor species (for example Golden Eagles and Bearded Vultures).
Wetlands and forests with suitable trees must be protected and or restored where damaged. Enough suitable trees for nest building need to remain in the forest (e.g. old beeches and pines). Disturbance during the breeding season (e.g. due to forest work) must be kept to a minimum.
Illegal persecution where it still occurs (e.g. Hungary, Austria, Germany or Ireland) must be stopped and the culprits should be punished according to the local laws.

Status IUCN/BirdLife

Least Concern (LC)

Status Global Raptor Information Network

Lower risk

Interviews about the White-tailed Eagle

Interview with Alv Ottar Folkestad about the White-tailed Eagle in Norway

Interview with Remo Probst about the White-tailed Eagle in Austria

Interview with Emil Todorov about the White-tailed Eagle in Bulgaria

Interview with Dejan Bordjan about the White-tailed Eagle in Slovenia

Interview with Claire Smith about White-tailed Eagles in Scotland and the reintroduction project in eastern Scotland

Interview Maxim Gavrilyuk about the White-tailed Eagle in Ukraine

References

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

[Dürr & Langgemach 2006]. Dürr, Tobias & Langgemach, Torsten (2006). Greifvögel als Opfer von Windkraftanlagen in Deutschland. Großvogelschutz im Wald. Jahresbericht 2006. Projektgruppe Seeadlerschutz.

[Fischer 1984] Fischer, Wolfgang (1984). Die Seeadler, 4. Auflage, Die Neue Brehm-Bücherei, Ziemsen Verlag, Wittenberg-Lutherstadt.

[GRIN 2009] Global Raptor Information Network. 2009. Species account: White-tailed Eagle Haliaeetus albicilla. Downloaded from http://www.globalraptors.org on 26 Aug. 2009

[Horváth 2009] Horváth, Zoltáan (2009). White-tailed Eagle (Haliaeetus albicilla) populations in Hungary between 1987-2007. (published in Probst 2009]).

[Kieckbusch & Koop 2008] Kieckbusch, Jan Jacob & Koop Bernd (2008); Seeadler beeinflussen die Kormoran-Brutbestände; In Großvogelschutz im Wald, Jahresbericht 2008 page 4-5; published by Projektgruppe Seeadlerschutz Schleswig Holstein e.V.

[Krone et al. 2009] Krone, Oliver & Kenntner, Norbert & Tataruch, Frieda (2009); Gefährdungsursachen beim Seeadler (Haliaeetus albicilla). (published in [Probst 2009])

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

[Nadjafzadeh & Krone 2008] Nadjafzadeh, Mirjam & Krone, Oliver (2008). Nahrungsspektrum und Fressverhalten des Seeadlers (Haliaeetus albicilla) in Norddeutschland; Bleivergiftungen bei Seeadlern: Ursachen und Lösungsansätze, page 31-43; Leibniz-Institut für Zoo- und Wildtierforschung (IZW), Berlin

[Probst et al. 2009] Probst, Remo & Kohler, Bernhard & Krone, Oliver & Ranner, Andreas & Rössler, Martin (2009). Schutzanforderungen für den Seeadler im Herzen Europas - Ergebnisse des Workshops der WWF-Österreich Tagung in Illmitz, 18. November 2007. (published in [Probst 2009])

[Probst 2009]: Probst, Remo (Hrsg.; 2009). Der Seeadler im Herzen Europas - Tagungsband der WWF Österreich Seeadler Konferenz von 17.-18. November 2007 in Illmitz - Denisia 27: 172 pp.

Books

[Fischer 1984] Fischer, Wolfgang (1984). Die Seeadler, 4. Auflage, Die Neue Brehm-Bücherei, Ziemsen Verlag, Wittenberg-Lutherstadt.

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.

Websites

BirdLife Species Factsheet for the White-tailed Eagle

GRIN species account for the White-tailed Eagle

Roy Dennis, Highland Foundation for Wildlife

Projektgruppe Seeadlerschutz

White-tailed Eagle in Poland

White-tailed Eagle in Austria

White-tailed Eagle reintroduction in Ireland