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Each year Uģis Bergamnis, the senior environmental expert of JSC “Latvijas valsts meži”, carries out monitoring of lesser spotted eagles in Latvia and rings them so that they could be recognised in the following years and to follow the nesting success of lesser spotted eagles and their habits in our forests.

The LVM expert has been researching lesser spotted eagles for several decades: “Monitoring is a biological data acquisition system with two important points. Firstly, unified methodology, and, secondly, long-term period when birds are monitored,” explains Uģis Bergmanis.

Six species of eagles nest in Latvia – lesser spotted eagle, greater spotted eagle (very rarely encountered), golden eagle, white-tailed eagle, osprey and short-toed eagle. The lesser spotted eagle is the most abundant, usually they nest in mature mixed tree or deciduous tree forests, build nest mostly in tops of spruce, birch, aspen and oak trees.

The ringing of eagles is done together with the monitoring of nesting success. If a young eagle is found in the nest, it is ringed with a ring of Latvian Ringing Centre and also with an orange aluminium ring that can be recognised from afar.

The ringing of young birds is carried out in mid July when they are almost fully grown. However, the mature eagles are ringed at the beginning of August, when meadows are cut, fields are harvested, thus it is easier to get closer to the nesting region and bring the bird catching equipment with an off-road car. A real, tamed white-tailed eagle as a decoy and a large net is used to catch mature eagles. Nesting lesser spotted eagles by defending their territory and the young eagle and their hunting territory are attacking the white-tailed eagle and get entangled in the net. Mature eagles are also ringed with the coloured rings.

“An eagle can build its nest in three days,” says the LVM expert. Eagle is frequently changing its nest with other vulture bird species – common buzzard – thus, the most difficult part of the monitoring is to understand which nest is inhabited by an eagle. Common buzzard returns earlier to Latvia and is the first to select its nest. When lesser spotted eagle comes and sees that his nest is already taken, he either builds a new nest or uses some other already existing nest. The lasting of nesting in one territory is determined by the suitability of forest for more nests, and also from suitable hunting territory near the nest.