The Biology of the Species
Measuring from 69 to 91 cm, the white-tailed eagle is one of the large birds of pray in Slovenia. Even more. It is a true glider with its wing span between 220 and 250 cm. Females are slightly larger than males. Its head is somewhat paler and has a large yellowish beak. Young white-tailed eagles have a dark coloured plumage. The adult birds have a short wedge-shaped white tail and long gliding wings. The species belongs to a class of typical gliders since it skilfully manipulates air currents. Airborne, it is less agile and therefore more vulnerable to low flying air-crafts and large windmills. The old Slovenian name for this species is Jezerec (Laker), indicating its primary feeding habitat. Mainly, it hunts fish in the upper water layers (carps, wels catfish, etc.). It also feeds on foxes, hares, young roe deer, and even carrion in winter. It builds a large tree nest near water. The nesting period is in the first half of the year. In the month of March the female lays from 1 to 3 eggs. Chicks fly from their nests in the first half of June. Parents teach them hunting skills and caution them not to get injured during their hunting or get stuck in the water.
The species lives close to open water surfaces of lakes, accumulations, sea shores and large rivers where it feeds, while it nests near quiet forest areas in the tall trees or rocky cliffs.
It is very picky about its nest location and builds it far away from the civilisation. During the nesting season the white-tailed eagle becomes very sensitive to all kinds of disturbances, in particular during the laying of eggs. During the laying period the species is threatened by nest-predators (egg thieves, falconers) and nature photographers as well as others who deliberately or unintentionally intrude on their immediate environment.
The time when chicks fly from their nests for the first time is also considered as very risky. Inexperienced super precocials may land in the middle of forest with no possibilities to ride favourable air currents and continue their flight and gliding.
The species is found in small numbers. It is spread across the Europe and Asia. White-tail eagles prefer living near large standing and slowly flowing waters. There are some five pairs of white-tail eagles living in Slovenia. The first nest was found near the Reško lake. A larger concentration of these birds lives along the Sava river, e.g. at the Lonjsko polje, the Kopački rit, etc.
Conservation status of the species in the Kočevsko Special Protection Area: uncertain
One pair of white-tail eagle constantly is constantly seen in the area. In the recent years no successful brooding of chicks was recorded.
The key objective is to provide peace in the nesting and feeding habitat by the Reško lake with access restrictions. The nest by the Reško lake will be equipped with surveillance cameras. The winter feeding station will be also built and be supplied with carrion in the winter time. In the scope of the project, the bird-watch stations will be built to watch the white-tail eagle and other birds, while aslo the boating and fishing will be prevented along the upper part of the lake by constructing a barrier on the lake which is protected as a fish reserve. A wooden protection fence against the cattle along the upper part of the lake will prevent cows a direct access to the lake. An educational path with didactic tools at the lower part of the lake will inform visitors about the surrounding nature, forest, the white-tail eagle and other Natura 2000 species.
In Slovenia, the white-tail eagle is a protected species. The white-tailed eagle is defined as a vulnerable species (VU) on the Red List of Threatened Species (2011 IBA revision).