The diet of the greater spotted eagle (Aquila clanga) in Belarusian Polesie

Abstract

During 1999-2009 the food remains from the nests of 43 breeding pairs of the greater spotted eagle in Belarusian Polesie (southern Belarus) were collected. 797 prey items were determined, including mammals (40%, 15 species and Sylvaemus sp., 4 orders), birds (36%, 35 species and Phylloscopus sp., Corvidae sp., 11 orders), evertebrates (16%, Coleoptera, Odonatoptera, Gastropoda), reptiles (6%, 4 species and Lacerta sp.), amphibians (1%, Rana sp.) and fish (1%, 3 species). Small rodents from the genus Microtus (M. arvalis and M. oeconomus) as well as Arvicola amphibius were the most numerous mammal species, followed by Erinaceus roumanicus and Talpa europaea. Rallidae (mostly Rallus aquaticus, Porzana porzana and Crex crex), waders (mainly Galinago gallinago), dabbling ducks (mainly Anas platyrhynchos and Anas querquedula), Galliformes (Lyrurus tetrix), Ciconiiformes (Ardea cinerea and Botaurus stellaris) were the most numerous bird prey species. Emberiza schoeniclus was predominated prey species among Passerines. Reptiles were frequently represented by snakes (mainly Natrix natrix, but also Vipera berus and Coronella austriaca). Biomass predominance in diet of the greater spotted eagles is as follows: birds (67.9%), mammals (25.3%), reptiles (3.4%), fish (3.0%) and amphibians (0.3%). Prey species with a body mass of 51-200 g (41.9%) and 11-50 g (38.3%) were predominant in the food spectrum of the greater spotted eagles. In the weight category of 1-50g, mammals were dominant, but from the categories of 51-200 g and heavier, birds occupied the leading position. The prey which made the largest contribution in total biomass of the greater spotted eagle were in the prey weight category from 601 to 1200 g (34%), then from 51 to 200 g (24%), from 11 to 50 g (16.6%) and more than 1200 g (16%). The species of the genus Microtus were equally represented in prey set of the greater spotted eagle in habitats with different degrees of anthropogenic transformation (24% in each habitat type). The share of Arvicola amphibius in the diet of the greater spotted eagle decreased from 12% in natural habitats to 4% in transformed habitats; the share of birds decreased from 41% to 26% correspondingly. The share of Insectivora and Evertebrata, on the contrary, increased to 3% and 11% in natural habitats and to 6% and 27% in transformed habitats correspondingly.Abstrakt: V rokoch 1999-2009 boli zozbierané vzorky potravy z hniezd 43 hniezdiacich párov orlov hrubozobých v Bieloruskom Polesí (južné Bielorusko).797 identifikovaných vzoriek potravy zahŕňalo cicavce (40 %, 15 druhov a Sylvaemus sp., 4 rady), vtáky (36 %, 35 druhov a Phylloscopus sp., Corvidae sp., 11 radov), bezstavovce (16 %, Coleoptera, Odonatoptera, Gastropoda), plazy (6 %, 4 druhy a Lacerta sp.), obojživelníky (1 %, Rana sp.) a ryby (1 %, 3 druhy). Malé hlodavce rodu Microtus (M. arvalis a M. oeconomus) ako aj Arvicola amphibius boli najpočetnejšími druhmi cicavcov, nasledované druhmi Erinaceus roumanicus a Talpa europaea. Rallidae (hlavne Rallus aquaticus, Porzan...

Habitat alteration enables hybridisation between Lesser Spotted and Greater Spotted Eagles in north-east Poland

“…Our results show a significant variation in habitat preferences between LSE and GSE, which are sympatric in the Biebrza Valley. Occurrence of GSE in areas that are wetter and have more shrubs than those occupied by LSE is consistent with earlier observations of habitat preference of these two species in the Biebrza Valley (Pugacewicz 1995 ) and in Belarus (Ivanovsky 1996 , Dombrovski andIvanovsky 2005 ). Similarly, the observed habitat preferences of LSE agree with the results obtained by other authors, mainly with respect to the strong preference for grassland and nesting close to open areas (Treinys 2004, Mirski 2009, Zub et al 2010.…”

“…The expected pattern in our study was: GSE -mixed pairs -LSE, or the opposite, depending on the variable tested. This pattern assumes that GSE is the most specialised species (see Pugacewicz 1995, Dombrovski & Ivanovsky 2005, Lõhmus & Väli Ü. 2005, Dombrovski 2012 ) which: (1) to the highest extent avoids breeding in the vicinity of human settlements; (2) selects areas located deeper in the forest and less accessible for man; (3) utilises areas located the closest to the river bed (the source of spring floods); (4) nests in the oldest tree stands; (5) avoids urbanised areas, arable and forest land; meadows and pastures and farmland mosaics as they are not the most attractive foraging areas; and (6) shows preference for marsh areas and highly natural habitats, such as shrubland and wetland.…”

“…data). Both GSE and LSE build their nests in forest edges and they tend to hunt across open ground (Cramp and Simmons 1980, Dombrovski et al 2000). There are a number of important differences in habitat selection between the two species.…”

“…voles, passerines and frogs; Treinys and Dementavičius 2004, Zub et al 2010), while GSE prefers medium sized prey (e.g. ducks, waders, rails and water voles Arvicola amphibius , if available; Väli and Lõhmus 2002, Dombrovski 2010, Maciorowski 2013).…”

The importance of wetlands for the Greater Spotted Eagle Clanga clanga wintering in the Mediterranean Basin

“…In these areas its main prey includes various wetland bird species (ducks, waders, rails), rodents (e.g. water vole Arvicola amphibius ) and amphibians (Graszyński et al 2002, Väli and Lõhmus 2002, Dombrovski and Ivanovski 2005, Maciorowski et al 2005, Dombrovski 2010). Drainage of wetlands has been reported as a major cause of their decline and indirectly the reduction of population size may accelerate hybridisation with the Lesser Spotted Eagle Clanga pomarina (Lõhmus and Väli 2005, Maciorowski and Mirski 2014, Maciorowski et al 2015a).…”