The aim of the monitoring activities is to investigate the impact of the approaches implemented within the conservation activities for the protection of the Lesser Spotted Eagle

Monitoring of

the Lesser Spotted Eagle

The monitoring of the Lesser Spotted Eagle starts after the spring migration of the species to its breeding sites and covers the period between the occupation of the breeding territories and the flight of the young birds out of the nests (March-August). In the second half of March and in April, visits to the breeding territories of the species are carried out to establish the presence of pairs in them and their status. In May-August, observations are conducted to identify newly occupied territories and the approximate location of eagles’ nests. Field experts enter the collected data directly into the specially developed SmartBirds Pro application, through which the information is uploaded to the BSPB ornithological database.

The search for the exact location of the nests of Lesser Spotted Eagles is carried out mainly in the autumn-winter period (November-March), after the leaves shedding of broadleaf forests – main nesting habitat of the species. In cases where the eagles’ nest is in lower canopy cover forests or on single trees, the nest search is carried out during the brood-rearing period (June-July) or in the pre-breeding period (March-April). All suitable trees are checked for the presence of nests. The coordinates of each nest found are taken with GPS and re-entered into SmartBirds Pro. All nests found during the fall/winter season are checked again in the spring to determine if they are occupied by Lesser Spotted Eagles or other raptor species.

Once all active nests have been identified, regular visits are made to determine the status of the pairs. The first visit is conducted in May to establish if pairs are breeding or not. If so, a second visit is conducted in June/July to establish the number of hatchlings. The third visit takes place in July/August to establish the number of fledged chicks. The following nesting parameters are considered during the survey:

nesting success

 number of fledged chicks/number of incubating pairs;

success rate

 (number of successful pairs)/(number of incubating pairs) x 100;

nesting rate

(number of incubating pairs)/(number of monitored pairs) x 100.


number of survived fledglings/number of occupied areas.

Breeding pairs are those that have started incubating. Breeding is considered successful when the pair has raised at least one chick that has fledged from the nest or has reached 80% of the average age for fledging. More information on all these indicators is provided by photo traps installed in the nests of five pairs of Lesser Spotted Eagles.

After the young Lesser Spotted Eagles have fledged, each nest which had a brood is visited during September-October and food debris is collected from the nest, the perimeter below the nest, and the areas used by the birds for resting. The collected material is determined with the help of the osteological collections of National Museum for Natural History-Bulgarian Academy of Sciences by a team of ornithologist, mammologist and herpetologist.

Thus information on the diet of Lesser Spotted Eagles is obtained. SmartBirds Pro is an application for professional use in conducting specialized monitoring, as well as for single observations of amateur naturalists. Thanks to it, each of us can contribute to tracking changes in Bulgarian populations of wild birds, mammals, amphibians, reptiles, invertebrates, and protected species specifically. By installing the app on your Android mobile device, you can record every wild animal you observe.


the impact

of the implemented


In addition to monitoring the Lesser Spotted Eagle, the project also carries out monitoring of the impact of the implemented activities on the stakeholders‘ attitude towards the LSE.

Initially, three types of information will be collected – on the attitudes of project stakeholders, on important socio-economic parameters of the Natura 2000 project areas and on the ecosystem services of key Lesser Spotted Eagle habitats.

Hundred on-site interviews will be carried out once specific representatives of the key stakeholders have been identified. The results of these interviews will be analysed and summarised in a Public Attitude Assessment Report.

In addition, a Socio-Economic Impact Report and an Assessment Report on the Ecosystems and their Services affected by the implementation of the project activities will be prepared. The above three reports can be considered as baseline reports that capture the situation at the beginning of the project.  Three similar final reports will be prepared at the end of project implementation to provide information on the actual impact of the project activities.

All activities

Scientific Research






Campaign to prevent crimes against wildlife