2016

Lesser Spotted Eagles Get Their Leg Bands

Each year, Uģis Bergmanis, Senior Environmental Expert of JSC “Latvia's State Forests” (LVM) carries out monitoring of lesser spotted eagles, by banding the birds with rings, which helps exploring bird life expectancy, migration routes, wintering areas, as well as the size of the nesting areas and origin of the nesting eagles.

"Leg-banding of the eagles is carried out together with examination of their nesting success. If a young eaglet is found in the nest, it is banded with a ring of the Latvian Ringing Centre, as well as with an orange aluminium ring for the identification of the bird from a distance," says the Environmental Expert.

Banding of young birds takes place in mid-July, when they are practically grown up. In turn, adult eagles are ringed in early August, when the meadows are mowed, fields of crops threshed, making it easier to access the sites by off-road vehicles, delivering the trapping equipment to the nesting areas.

For trapping of adult eagles, a tamed sea eagle and a large net are used as a decoy-duck. Nesting lesser spotted eagles in defence of their territory and the young eagle, attack the sea eagle and get entangled in the net. Also adult eagles are ringed with coloured rings.

"An eagle can make a nest in three days," says the LVM Expert. Eagles often change their nests with another species of birds of prey - the common buzzard; therefore the greatest challenge is to understand where the eagles nest. The common buzzard comes to Latvia earlier and chooses its nest first. When the lesser spotted eagle arrives and finds that its nest is already taken, it either makes new nest, or uses a nest that is already made. Nesting durability in a given area is determined by the suitability of the forest for making several nests, as well as by the availability of suitable hunting areas near the nest.

Six species of eagles nest in Latvia: lesser spotted eagle, spotted eagle, which is a very rare species, golden eagle, sea eagle, osprey and serpent eagle. The lesser spotted eagle is the most common species, and it usually nests in mixed forests and deciduous forests, and makes its nest in spruces, birch-trees, aspens and oaks.

LVM Expert Uģis Bergmanis has been engaged in studies with lesser spotted eagles already for several decades. Monitoring is a biological data acquisition system consisting of two important elements: a common methodology and a lengthy period when the bird observation is carried out.