Productivity and diet of lesser spotted eagle (Aquila pomarina) in Lithuania in 2001-2003

In 2001-2003, the data on the productivity and diet of Lesser Spotted Eagle (Aquila pomarina) were collected in Central, Northern and Eastern parts of Lithuania. Though during the mentioned period productivity varied greatly, mean productivity of 0.61 was very similar to that more than 10 years ago. During the study period successful breeders made up 59%; 3% of all successful breeding attempts resulted in two nestlings. The productivity correlated with the share of small rodents in the diet. With a decrease of the diet share of small rodents, the diet share of amphibians increased. Therefore we assume that Lesser Spotted Eagle in the study area behaves partly according to the alternative prey hypothesis. It is also likely that during the last decade small rodents became predominant in the diet of eagles, whereas the role of other kind of prey became less significant. Extensive agriculture can be one of the possible reasons for this. We also suggest that changes in agriculture during the last decade did not have direct influence on mean productivity. Due to the lack of data we are not able to judge about changes in population abundance.

Rimgaudas Treinys, Deivis Dementavius, Acta Zoologica Lituanica, 2004, Volumen 14, Numerus 2