218 Acta Zoologica Lituanica, 2005, Volumen 15, Numerus 3 ISSN 1392-1657 NEW DATA ON NUMBERS AND DISTRIBUTION OF BIRDS OF PREY BREEDING IN BELARUS Valery Cheslavovich DOMBROVSKI1, Vladimir Valentinovich IVANOVSKI2 1Institute of Zoology NAN B, Akademichnaya 27, 220072 Minsk, Belarus. E-mail: [email protected] 2APB-Birds Conservation Belarus, P.O. Box 306, 220050 Minsk, Belarus. E-mail: [email protected] Abstract. During 19982002, all species of diurnal raptors were counted in Belarus. The method used was observation of a study area with the help of optics from a series of points and subsequent mapping of the hunting and presumed nesting ranges of birds of prey. The total area surveyed was about 9,000 km². Estimated quantity of the species: Honey Buzzard 8,00011,000 pairs; Black Kite 200230; Red Kite 310; White-tailed Eagle 85105; Short-toed Eagle 530700; Marsh Harrier 6,0009,000; Hen Harrier 600800; Montagus Harrier 3,0005,000; Goshawk 3,5005,000; Sparrowhawk 6,500 8,500; Common Buzzard 18,00024,000; Lesser Spotted Eagle 3,2003,800; Greater Spotted Eagle 150200; Golden Eagle 2535; Booted Eagle 1015; Osprey 150180 pairs; Common Kestrel 1,2001,700; Red-footed Falcon 1030; Merlin 300350; Hobby 2,5002,700; Peregrine 03 pairs. Key words: birds of prey, number, distribution, breeding density, Belarus INTRODUCTION (Circus pygargus) and Marsh Harrier (Circus aerugi- nosus) in the last summary on birds of Belarus (Niki- Study of birds of prey in Belarus was rather irregular. forov et al. 1997). In the middle of the 20th century purposeful study of raptors was carried out only in Polesie (southern part of Belarus): in National Park Belovezhskaya pushcha MATERIAL AND METHODS (Datskevich 1997) and to a certain extent in Pripyatski Reserve (Klakotski 1976). Till the beginning of the Field studies 1980s due to contribution of Dr V. Ivanovski the centre During 19992002, in the framework of the project of scientific investigations of birds of prey moved to on study of number and distribution of Greater and Poozerie (northern part of Belarus). The rest of Belarus Lesser Spotted Eagles (Aquila clanga and Aquila territory has befallen from the field of vision of pomarina) in Belarus, supported by the RSPB, the specialists, and the materials during this time were col- BirdLife International partner in the UK, the counts of lected occasionally, at the same time with other counts rare birds of prey were carried out in the territory of of birds in the course of different faunistic expeditions. the Republic of Belarus. The counts of rare breeding As a result, last population estimates for birds of prey raptor species were carried out in 81 census plot with usually were based on materials obtained in Poozerie area of about 9,000 km². Additionally we used the data (northern part of Belarus) (Ivanovski 1990a, b; Red collected during different faunistic studies in 1993 Data Book of the Republic of Belarus 1993; Hagemeijer 2000 and results of counts of birds of prey in Polesski & Blair 1997). It has unpleasant consequences: popu- radio-ecological reserve in 1998 during expedition of lation estimates for some species with high numbers the Institute of Zoology, National Academy of Sciences in southern Belarus were lowered (Greater Spotted of the Republic of Belarus. Eagle (Aquila clanga), White-tailed Eagle (Haliaeetus The main method used in counting was visual obser- albicilla), Hen Harrier (Circus cyaneus)). It is necessary vation with the help of binoculars and telescopes (2060×) to mention also that attention of ornithologists was at- from a series of points at 23 km from each other and tracted mainly by rare species. Any census data on at a distance of 5001,000 m from the edge of the common species were absent. It was a reason of erro- forest observed (Dombrovski 1998a). The points were neous population estimates for several common species located so as each forest sector could be viewed several (for example, Honey Buzzard (Pernis apivorus), times from different perspectives. When suitable open Common Buzzard (Buteo buteo), Montagus Harrier areas were absent, counting from tops of tall trees 219 New data on numbers and distribution of birds of prey breeding in Belarus standing out above the area was practised. Duration of tification. Special attention was paid to birds with observation sessions was at least four hours. Best timing nesting behaviour (display, alert, aggressiveness, of observation was 10:00 a.m. 3:00 p.m., i.e. the bringing construction material and foodstuff to the time of main summer activity of birds of prey. On nest). Later the borders of the hunting and presumed cloudy and rainy days counts would either be cancelled nesting ranges were mapped. for the whole day, or would only start from the moment when permanent fine weather has re-established. Calculation of total population estimates of the Majority of study plots was inspected twice: in late birds of prey AprilMay during the period of active displays for main Study plots were selected in such a way, that all 25 geo- part of species of birds of prey, and in late JuneJuly, botanical units according to the scheme of Yurkevich et when adults actively hunt to rear the nestlings. al. (1979) were comprehended (Table 1, Fig. 1). All distinctive features of birds under observation were We used somewhat different approaches to calculate recorded (peculiar plumage colour, absence of pen- the population numbers of different species: feathers and tail feathers) for their individual iden- For the species which were recorded in our region dur- Table 1. Number and distribution of study plots for rare birds of prey species according to geo-botanical division of Belarus. See also Figure 1. Region Geo-botanical unit Area, km2 Number of plots Area of plots, km2 01 012,220 07 0,587 02 012,000 14 0,951 Region of lakes (Poozerie) 03 000,990 01 0,078 04 007,800 03 0,275 Total 033,010 25 1,891 05 007,075 06 0,386 MinskOshmiany 06 001,875 01 0,106 07 019,000 05 0,392 Total 027,950 12 0,884 08 014,500 02 0,230 OrshaMogilev 09 006,000 01 0,288 10 003,750 01 0,060 11 005,250 02 0,302 Total 029,500 06 0,880 12 012,150 07 0,332 13 002,750 03 0,304 Region of Neman 14 009,000 01 0,290 15 001,500 02 0,206 16 009,600 02 0,227 Total 035,000 15 1,359 17 008,600 03 0,286 Lower Berezina 18 006,000 02 0,292 19 011,400 03 0,314 Total 026,000 08 0,892 20 010,600 06 0,448 West Polesie 21 013,000 08 1,386 Total 023,600 14 1,834 22 008,300 02 0,300 23 005,000 02 0,264 East Polesie 24 006,400 03 0,447 25 012,250 05 0,400 Total 031,950 12 1,411 Grand total 207,010 92 9,151 220 Dombrovski V. C., Ivanovski V. V. given species was not counted in any geo-botanical unit, this district was excluded from further calculations of total population estimates. The calculations were based on vegetation map (1:500,000) and physio- geographical map (1:100,000 or 1:200,000). For the species that avoid the neighbourhood with man (Greater Spotted Eagle, Short-toed Eagle) we corrected the estimates according to the number of populated localities in given area. Counts of common, widely distributed species (Marsh and Montagus Harrier, Honey Buzzard, Common Buz- zard, Sparrowhawk (Accipiter nisus) and Goshawk (Accipiter gentilis)) were carried out in not all geo-bo- tanical regions of Belarus. Thus, we used for extrapo- lation the materials of counts in 25 study plots with total area of about 2,900 km². These study plots were located in main landscape types of Belarus (Table 3). Figure 1. Geo-botanical division of Belarus according to The extrapolation for total Belarus area was carried the scheme of Yurkevich et al. (1979). Numbers correspond out according to mean population density of species to botanical units (see Table 1). and total area of suitable habitats. ing breeding period, but were not counted during our censuses (Red Kite (Milvus milvus), Red-footed Falcon RESULTS AND DISCUSSION (Falco vespertinus) and Peregrine (Falco peregrinus)) we give only available facts of records. Honey Buzzard (Pernis apivorus). Common, widely For Golden Eagle (Aquila chrysaetos) we indicate all distributed species (Tables 3, 4). Till present the popu- known nesting areas where monitoring was carried out. lation numbers were underestimated because of rare For rare and protected species connected with some spe- breeding records (Nikiforov et al. 1997). According to cific habitat types (Black Kite (Milvus migrans), Short- results of our counts, this species is second the most toed Eagle (Circaetus gallicus), Greater and Lesser numerous species after the Common Buzzard. The high- Spotted Eagles, Booted Eagle (Hieraaetus pennatus), est density was recorded in deciduous broad-leaved for- White-tailed Eagle, Hen Harrier, Merlin (Falco ests alternated with open areas (23.4 pairs/100 km²). columbarius), Common Kestrel (Falco tinnunculus) Willingly occupies wet forests in the borders of peat and Hobby (Falco subbuteo)) the calculations were bogs, where sometimes is the most numerous species based on numbers of breeding pairs counted in study among raptors (Dzmitranok & Dombrovski 1999). Does plots (Table 2). The densities were extrapolated on the not avoid the neighbourhood with human settlements. area of suitable habitats for each geo-botanical unit. If So, in suburbs of Minsk in mosaic habitat with small Table 2. Breeding density of some rare bird of prey species in study plots in different geo-botanical regions of Belarus.