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The paper describes the observation in Belarus of an adult greater spotted eagle breeding female pale morph “fulvescens”, which retained the same light colour of plumage for five successive years. The data on the presence of pale morph adult birds in the collections of some zoo museums is also analysed.

The northern hawk owl is a real irruptive species that respond to irregular changes in the food supply. When prey levels are adequate, it breeds and winters within northern forests. Decreased prey availability can start winter invasions, the timing and magnitude of which are the subject of this study. Mainly the citizen data were extracted from the national bird websites to obtain data on the number of northern hawk owls observed in 2010–22. This paper demonstrates that through citizen data large amounts of information can be collected over wide areas, entire Europe in this case.

Przewalski’s wild horses (Equus ferus przewalski) are an endangered species and current conservation efforts aim to maintain genetic diversity and reintroduce wild populations. From 1998 to 2004, 36 Przewalski’s horses were introduced in the Chernobyl Exclusion Zone (CEZ) with no subsequent direct management, and current population size and genetic diversity are unknown. We used remote cameras positioned at the entrance of abandoned structures within the CEZ to elucidate visitation of these structures by Przewalski’s horses and other large mammals to assess the use of this method for monitoring the horse population within the CEZ. We estimated frequency of structure use in winter (Nov 2016–Feb 2017) and summer (Mar 2018–Oct 2018) periods and estimated basic group characteristics such as group type (all male vs. mixed sex), group size, and number of foals. Przewalski’s horses were detected 35 times at 9 of 10 monitored structures in winter and 149 times at all 8 monitored structures in summer. Eight other mammalian species were documented using abandoned structures. Mixed sex groups of horses contained 5.30 ± 0.25 adults and 1.00 ± 0.12 foals (mean ± S.E.). All-male groups contained 1.59 ± 0.15 individuals. Our data suggest Przewalski’s horses routinely use abandoned structures in the CEZ with visitation patterns tending to be nocturnal in winter and crepuscular in summer. Congregation of horses in these structures could have implications for future monitoring of the population by providing detailed information on demographics, population size, and genetic diversity which would benefit management plans for this population and provide a baseline for future work.

The diet of the greater spotted eagle (Aquila clanga) in Belarusian PolesieDuring 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 Sylvaemussp., 4 orders), birds (36%, 35 species and Phylloscopussp., Corvidae sp., 11 orders), evertebrates (16%, Coleoptera, Odonatoptera, Gastropoda), reptiles (6%, 4 species and Lacertasp.), amphibians (1%, Ranasp.) and fish (1%, 3 species). Small rodents from the genus Microtus(M. arvalisand M. oeconomus) as well as Arvicola amphibiuswere the most numerous mammal species, followed by Erinaceus roumanicusand Talpa europaea.Rallidae (mostly Rallus aquaticus, Porzana porzanaand Crex crex), waders (mainly Galinago gallinago), dabbling ducks (mainly Anas platyrhynchosand Anas querquedula), Galliformes (Lyrurustetrix), Ciconiiformes (Ardea cinereaand Botaurus stellaris) were the most numerous bird prey species. Emberiza schoenicluswas predominated prey species among Passerines. Reptiles were frequently represented by snakes (mainly Natrix natrix, but also Vipera berusand 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 Microtuswere 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 amphibiusin 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.

Colour ringing of the Spotted Eagles (Aquila pomarina, Aquila clangaand their hybrids) in Europe - a reviewDuring the years 2000-2008 1377 Spotted Eagles (SE) (Aquila pomarina, Aquila clangaand their hybrids) have been colour ringed in Europe. Out of these, 1303 (94.6 %) were young birds and 74 (5.4 %) were adults. Out of the total, 1290 (93.7 %) were the Aquila pomarinaLesser Spotted Eagles (LSE) - 1229 (95.3 %) young and 61 (4.7 %) adults, 50 (3.6 %) were the Aquila clangaGreater Spotted Eagles (GSE) - 44 (88.0 %) young and 6 (12.0 %) adults and 37 (2.7 %) were the Aquila pomarinax Aquila clangahybrids (LSE x GSE) - 30 (81.1 %) young and 7 (18.9 %) adults. With respect to the individual European countries the following SE species and numbers were ringed: Slovakia 636 (46.2 %), Poland 333 (24.2 %), Estonia 153 (11.1 %), Germany 116 (8.4 %), Lithuania 68 (4.9 %), Latvia 45 (3.3 %) and Belarus 26 (1.9 %). In the article authors presents a review on Spotted Eagle colour ringing programmes running in individual European countries.