[order] Falconiformes | [family] Accipitridae | [latin] Haliaeetus albicilla | [UK] White-Tailed Eagle | [FR] Pygargue queue blanche | [DE] Seeadler | [ES] Pigargo Europeo | [IT] Aquila di mare codabianca | [NL] Zeearend

Zeearend determination

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White tail and yellow bill as in Bald Eagle, but head and neck pale buff rather than pure white, contrasting much less with rest of plumage. tail wedge shaped. Female averages larger. Juvenile blackish brown, with tail, head, bill and iris all dark, whitish markings on axillaries. gradually attains adult plumage over 5-6 years, but tail not wite until 8th year, bill yellow after 4-5 years.

It is closely associated with wetlands, principally large lakes and rivers, from the lowlands to 5,000 m. It generally nests in trees near water and in upland areas on cliffs. Within its wide range the White-tailed Eagle breeds in quite different habitats, from the treeless marine fjords in Greenland and the outer coast of Norway to the brackish, forested coasts of the Baltic, and from the northern taiga lakes and rivers of Fennoscandia and Russia to the alluvial forests and floodplains in central and southern Europe. As always, a sufficient prey base is crucial for reproduction. Shallow waters with high production are essential in most areas. In forested areas nests are exclusively built in trees, and mature tree stands are needed for nesting. Being sensitive to disturbance at the nest, the Sea Eagle requires breeding sites with low human activity. The nearest acceptable distance to potential sources of disturbance varies strongly between areas, being larger in open habitats with exposed nests than in more secluded sites. A gradual relaxation in sensitivity to human disturbance has been observed recently in some areas, probably as a result of less persecution.
The species is very faithful to its breeding sites, with the same sites being occupied by generation after generation of eagles. This long continuity places special concern and attention to the long-term conservation of breeding areas, especially in our time of rapid change. When nesting in trees this big eagle builds huge nests which are added to year by year, and therefore needs strong nest-trees; such trees are usually much older than the rotation period in modern forestry

This bird is breeding in south-western Greenland, Iceland and in a large part of Eurasia, from the Balkan Peninsula, Germany and Norway to northern China and eastern Siberia. During last century and the first half of this century the species has declined dramatically and has disappeared from many regions. Since 1970 its western populations have increased, and have been able to become established again in several regions. In Central Europe and Greece the decrease is still going on, however. The population of the European Union was of 149-161 breeding pairs, while the total European population can be estimated at 3500 pairs. This species has been suffering and is still suffering in some regions from persecution, acute poisoning, nest destruction and wetland reclamation.
The White-tailed Eagle is a long-lived, slow-reproducing raptor, compensating for a low annual offspring production by high adult survival. This makes the species most sensitive to a decrease in adult survival, compared with a decrease in juvenile survival or a temporary decrease in productivity. A reduction in productivity over many years, however, will threaten the population, as demonstrated by the critical situation in the Baltic region from the 1960s until the mid-1980s as a result of contamination with pollutants. Despite the dangers, a juvenile reaching adulthood has a high chance of survival, birds live to over 35 years old.

Usually closely associated with water, the White-tailed Eagle feeds mainly on fish and water birds (ducks, coots, grebes, gulls etc.). Fish prey is taken close to the water surface and most hunting for fish is in shallow waters. During early summer, fish dominates the food in most areas, whereas birds increase in the diet later in the breeding season and in autumn and winter according to availability. Commercial fish-ponds are important feeding grounds for local populations in central and southern Europe. In some freshwater habitats, mammal prey is also readily utilized, e.g. muskrat. Birds are captured on the water and on the ground, rarely on the wing. Carrion is an important food source during winter. In some northern populations, carrion is an important source of food during the breeding season as well. Piracy of food, targeted at e.g. Osprey, gulls and cormorants, is often practiced. The White-tailed Eagle is quite capable both as a hunter and a fisher, although less agile than more specialized raptors.

Haliaeetus albicilla has been down listed to Least Concern, as a recent reassessment of its European population suggests that it no longer approaches the thresholds for the IUCN Red List criteria. Following a large recovery in many European countries during 1970-19903, the species continued to increase virtually everywhere during 1990-2000, including key populations in Norway and European Russia (which together hold >55% of the European population). A few small populations in extreme southeast Europe continued to decline, but these losses were outweighed by large increases farther north and west. The European population is now estimated at 5,000-6,600 pairs, encompassing 50-74% of the global population. Although some losses may be taking place in Asian Russia due to increased logging and oil industry development, these are outweighed by increases in Europe. Populations in Kazakhstan are also increasing. The species has its strongholds in Norway and Russia, and important populations in south-west Greenland (to Denmark), Sweden, Poland and Germany. Smaller numbers breed in Iceland, United Kingdom, Finland, Estonia, Latvia, Lithuania, Belarus, Austria, Czech Republic, Slovakia, Slovenia, the former Yugoslav states, Bulgaria, Romania, Hungary, Moldova, Greece, Turkey, Iran, Armenia, Georgia, Azerbaijan, Ukraine, Kazakhstan, Turkmenistan, Mongolia, mainland China, and Japan. It formerly bred in Algeria and may still do so in Iraq. It requires large and open expanses of lake, coast or river valley, within the boreal, temperate and tundra zones, nearby to undisturbed cliffs or open stands of large, old-growth trees for nesting. Its food is vertebrates (fish, mammals and especially birds), from marine, freshwater and terrestrial environments. It is mainly migratory in the north and east of its breeding range, but sedentary elsewhere. Threats that affect this species include loss and degradation of wetlands, human disturbance and persecution, environmental pollution, collision with wind generators, and indiscriminate use of poisons. Modern forestry methods reduce the availability of suitable nesting habitat. [conservation status from birdlife.org]

First reproduction usually from age 5 (6th calendar year), sometimes as early as 3 or as late as 7+. Territorial pairs are highly faithful, generally occupying the same territory throughout life, and territories tend to be occupied by succeeding generations of eagles. Several territories have been occupied by Sea Eagles for a century or more. As populations increased again in recent years, old vacant territories were the first to be re-occupied by new eagles, after a pause of 20 - 40 years. The nests are built in trees or on cliff ledges, or on the ground as locally in Greenland, Iceland, Norway and rarely elsewhere. Nesting also occurs rarely on pylons, towers. In forested areas, tree-nesting is preferred and mature trees are clearly favored to support the huge nests. The age of nest-trees are usually well above the rotation period in forestry (as long as such trees are available).
In the taiga and sub-boreal forest region most nests are in pine Pinus silvestris, whereas in Central and Southern Europe nests are commonly found also in deciduous trees. Nests are generally placed in the top third of the tree. Normally, two or more alternate nests are found in a breeding territory. Utilizing a mainly stable prey base, the breeding frequency is high (c90% in Swedish populations. The time of egg-laying varies with latitude and climate, starting in late January in southern Europe, mid-February in the Baltic Sea and late March or early April in the northern more continental areas. Most pairs in a population usually lay within a period of 3 - 4 weeks. Clutch size 1-3 (very rarely 4), mean 2.1 but lower in some northern populations. Incubation period 35 - 38 days, nestling period 70-86 days. Nestlings grow from c80 - 95 g at hatch to 4-6 kg at fledging, the steepest gain in weight occurring during the first 5 weeks of life. Fledged young are usually dependent on the parents for food for 1 -2 months and disperse from the territory c2 - 3 months after fledging. Annual breeding success (pairs rearing young) in healthy populations is usually c60-80% and brood size 1.6 - 1.8.

Resident, dispersive, or migratory according to latitude and age-class. Apparently wholly migratory in Russia north of c. 60N, where fresh waters freeze and waterfowl prey absent in winter; elsewhere in west Palearctic, most adult pairs strictly resident all year, though juveniles and immatures wander extensively, mainly south to south-west. Young tend to be gregarious in winter where common; small numbers reach Iraq, Israel, and north Mediterranean west to Spain, and stragglers to North Africa.