The eagle of the forests
The lesser spotted eagle is smaller than most other eagles in Bulgaria. Still, its wingspan can reach 145 cm, but it weighs no more than 1600 grams.
As with many raptors, females and males look alike, with just a minor difference in size, so there is almost no sexual dimorphism. However, differences can be observed between the young and the adult birds. The young of the lesser spotted eagle are chocolate brown with a prominent golden patch on their nape. The adults have brown plumage.
In the breeding season the lesser spotted eagle often emits a squealy ‘wiiik, wiiik’, and in the other seasons it is identified by its repetitive ‘k-ye k-ye’ call that resembles the yelps of a small dog.
The eagles’ menu
Lesser spotted eagles feed on small mammals, mainly voles and other prey of similar size: rodents, amphibians, reptiles, small birds and insects. The pairs on Sakar Mountain catch also hedgehogs which is regarded as a feeding adaptation for the species.
Threats to the lesser spotted eagle
Helping the eagle
According to research lesser spotted eagles prefer to nest at the forest edge, near open spaces with scrub-grass communities in the forests, or near agricultural land in the vicinity of territories with available and accessible food resources. Good practices and models for the improvement and sustenance of feeding grounds and food resources for the species include:
restoration of abandoned grass and scrub-grass communities;
transformation of arable land into pastures or implementing favorable schemes for culture rotation;
restoration of scrub vegetation;
pasture rotation and effective management;
construction of food trenches and other methods to increase the abundance of animals that the species uses as a source of food.
The practices for the creation, restoration and sustenance of forest landscape structures and sections of the forest edge near open spaces include:
the creation and restoration of forest shelter belts that are important as rest stops during migration, as well as in the breeding season of the lesser spotted eagle;
restoration and sustenance of transitional tree-scrub vegetation (ecotone) as a key habitat for the species that form the diet of the lesser spotted eagle.
Satellite tagging of lesser spotted eagles
In the summer of 2020 for the first time in Bulgaria three young lesser spotted eagles of the local population were tagged with GPS/GSM transmitters. The transmitters are fitted on the young eagles when they are about to leave the nest and have already reached the size and strength of adult birds. The transmitters are small devices that are fitted on the back of the birds with specially designed straps. They weigh only 70 g so the birds get used to them and they can carry them all their life. The transmitters have solar panels to charge their battery so they have a long life span.
Tagging lesser spotted eagles with transmitters will contribute to revealing the model of dispersion of the young individuals, their migration routes, their rest stops; it will also facilitate the collection of important data about the threats they face in their wintering grounds, as well as along their migration route.
Satellite tracking will enhance research on the habitats lesser spotted eagles use and prefer, as well as on the life span of the species. The collected data will contribute for the preparation of a demographic model for the species, and it will outline the main directions for a more effective conservation not only regionally but globally too.
You can follow the stories of Kubrat, Tervel and Svoboda – the three lesser spotted eagles that were tagged with transmitters, – on the map here.
Safe electricity pylons and poles
There are several ways to make power lines safe for the birds:
Replacement of overhead power lines that are dangerous for the birds with underground lines. This approach completely eliminates the risk of electrocution or collision for the birds and guarantees a reliable energy supply for people.