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Aug 27 2011

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White-tailed Eagle (Haliaeetus albicilla)

White-tailed Eagle

[order] ACCIPITRIFORMES | [family] Accipitridae | [latin] Haliaeetus albicilla | [authority] Linnaeus, 1758 | [UK] White-tailed Eagle | [FR] Pygargue a queue blanche | [DE] Seeadler | [ES] Pigargo Europeo | [NL] Zeearend

Subspecies

Monotypic species

Genus

Members of the genus Haliaeetus are large to very large eagles, with long, broad wings and medium to short rounded or wedge-shaped tails. The bill is large, strong and compressed. The legs are short and the toes and talons powerfully developed

Physical charateristics

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.

Listen to the sound of White-tailed Eagle

[audio:http://www.planetofbirds.com/MASTER/ACCIPITRIFORMES/Accipitridae/sounds/White-tailed Eagle.mp3]

Copyright remark: Most sounds derived from xeno-canto


wingspan min.: 190 cm wingspan max.: 240 cm
size min.: 76 cm size max.: 92 cm
incubation min.: 34 days incubation max.: 42 days
fledging min.: 75 days fledging max.: 42 days
broods: 1   eggs min.: 1  
      eggs max.: 3  

Range

Eurasia : widespread

Habitat

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

Reproduction

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.

Feeding habits

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.

Video White-tailed Eagle

httpv://www.youtube.com/watch?v=LCvq52_mj54

copyright: youtube


Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size may be moderately small to large, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
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.
White-tailed Eagle status Least Concern

Migration

Resident, dispersive, or migratory according to latitude and age-class. Apparently wholly migratory in Russia north of c. 60 degrees N, 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.

Distribution map

White-tailed Eagle distribution range map

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