Орлан-белохвост в Нижегородской области, Россия

• Main Authors: Бакка, С., Киселева, Н.
• Format: Text
• Language: unknown
• Published: Общество с ограниченной ответственностью «Сибэкоцентр» 2008
• Subjects: ХИЩНЫЕ ПТИЦЫ; ПЕРНАТЫЕ ХИЩНИКИ; ОРЛАН-БЕЛОХВОСТ; Bakka; Sura; Haliaeetus albicilla; White-tailed eagle; Aquila chrysaetos; Pandion haliaetus; Орлан-белохвост
• Online Access: http://cyberleninka.ru/article/n/orlan-belohvost-v-nizhegorodskoy-oblasti-rossiya; http://cyberleninka.ru/article_covers/14731926.png

The White-Tailed Eagle (Haliaeetus albicilla L.) was listed in the Red Data Book IUCN at the end of ХХ century. The number of the species was stopped to decrease and began to restore in Western Europe and several regions of Russia in 1980-s. The positive trend of the species number in the N. Novgorod district has not been noted recently. However registrations of adults and young birds, finds of new nests in 2006-2007 have caused to project number of species appreciably increasing. It has induced us to generalize all the collected data on the White-tailed Eagle in the N. Novgorod district. For processing data we used GIS-software. As a result we created the database including 57 breeding territories which were divided into 5 categories: confirmed confirmed breeding; possible records of adults in the breeding season or juveniles; probable -records of birds during breeding season following data of the local people questionnaire and are not checked up; single birds were registered or the White-tailed Eagle records were up to 1990; potential suitable site for breeding in the zone continuously inhabited by eagle c suitable habitats; vanished a site where the nest destruction and loss of conditions for breeding are confirmed. Probably no less than 80-100 pair of White-tailed Eagles bred in the N. Novgorod district at the beginning of XX century, that estimations were some greater than modern number. Birds inhabited riparian forests in the Volga, Oka, Sura, Vetluga river valleys. The species number was not decreased up to 1940-50-s and regularly noted on all islands and shallows of the Oka and Volga rivers that time (Puzanov et al., 1955). According to E.M. Vorontsov (1967), White-tailed Eagles were noted more often, than Golden Eagles (Aquila chrysaetos). All information about the species breeding were exhausted findings of 3 nests which have been cut down during the clearing of the Cheboksarskiy water reservoir bed and one living nest which subsequently has fallen down together with the tree in 1981-94. Following data of modern surveys under conditions of obvious increasing the number of the White-tailed Eagle we can not speak about regular records of the species«on all islands and shallows of the Oka and Volga rivers», however more than 10 nests have already known. Probably there was the sharp decreasing the number of the White-tailed Eagle since 1950-s to the middle of 1980-s. In the middle of 1990th A total of 4-7 pairs were estimated to breed in the district (Bakka, Bakka, 1997). Later the positive trend was noted. And following information in the Red Data Book of the N. Novgorod district (2003) a total of 7-9 pairs bred in the district. Analyzing data of the White-tailed Eagle records and using GIS-software (Table 1) we can give new estimations of number and distribution of the species in the district. Now a total of 40-60 pairs are projected to breed in the N.Novgorod district. Modern parameters of the White-tailed Eagle distribution in different habitats are presented in the Table 2. The minimal distance between neighbors was 3 km. The distance between neighbors was 3-4 km in optimal habitats in the Unzha spur of the Gorki water reservoir and in the left side of the Cheboksarskiy water reservoir opposite to the Sura river. We observed 10 nests of the White-tailed Eagle. They located on trees of three species: pine (7 nests), poplar (2) and oak (1). The height of nest locations ranged from 15 up to 20 m, an average of 16.8 m. All nests found on banks of the Gorki water reservoir were built on pines. Nests found on banks of thr Cheboksarskiy water reservoir were on deciduous trees. We only twice registered White-tailed Eagles nesting on platforms installed on pines. In contrast to Golden Eagles and Ospreys (Pandion haliaetus), it seems that White-tailed Eagles have not yet preferred artificial nests. The average brood size was 1.33±0,5 fledglings (n=9; range 1-2). We twice registered White-tailed Eagles wintering near nonfreezing sites of the Volga river. The White-Tailed Eagle (Haliaeetus albicilla L.) was listed in the Red Data Book IUCN at the end of ХХ century. The number of the species was stopped to decrease and began to restore in Western Europe and several regions of Russia in 1980-s. The positive trend of the species number in the N. Novgorod district has not been noted recently. However registrations of adults and young birds, finds of new nests in 2006-2007 have caused to project number of species appreciably increasing. It has induced us to generalize all the collected data on the White-tailed Eagle in the N. Novgorod district. For processing data we used GIS-software. As a result we created the database including 57 breeding territories which were divided into 5 categories: confirmed confirmed breeding; possible records of adults in the breeding season or juveniles; probable -records of birds during breeding season following data of the local people questionnaire and are not checked up; single birds were registered or the White-tailed Eagle records were up to 1990; potential suitable site for breeding in the zone continuously inhabited by eagle c suitable habitats; vanished a site where the nest destruction and loss of conditions for breeding are confirmed. Probably no less than 80-100 pair of White-tailed Eagles bred in the N. Novgorod district at the beginning of XX century, that estimations were some greater than modern number. Birds inhabited riparian forests in the Volga, Oka, Sura, Vetluga river valleys. The species number was not decreased up to 1940-50-s and regularly noted on all islands and shallows of the Oka and Volga rivers that time (Puzanov et al., 1955). According to E.M. Vorontsov (1967), White-tailed Eagles were noted more often, than Golden Eagles (Aquila chrysaetos). All information about the species breeding were exhausted findings of 3 nests which have been cut down during the clearing of the Cheboksarskiy water reservoir bed and one living nest which subsequently has fallen down together with the tree in 1981-94. Following data of modern surveys under conditions of obvious increasing the number of the White-tailed Eagle we can not speak about regular records of the species«on all islands and shallows of the Oka and Volga rivers», however more than 10 nests have already known. Probably there was the sharp decreasing the number of the White-tailed Eagle since 1950-s to the middle of 1980-s. In the middle of 1990th A total of 4-7 pairs were estimated to breed in the district (Bakka, Bakka, 1997). Later the positive trend was noted. And following information in the Red Data Book of the N. Novgorod district (2003) a total of 7-9 pairs bred in the district. Analyzing data of the White-tailed Eagle records and using GIS-software (Table 1) we can give new estimations of number and distribution of the species in the district. Now a total of 40-60 pairs are projected to breed in the N.Novgorod district. Modern parameters of the White-tailed Eagle distribution in different habitats are presented in the Table 2. The minimal distance between neighbors was 3 km. The distance between neighbors was 3-4 km in optimal habitats in the Unzha spur of the Gorki water reservoir and in the left side of the Cheboksarskiy water reservoir opposite to the Sura river. We observed 10 nests of the White-tailed Eagle. They located on trees of three species: pine (7 nests), poplar (2) and oak (1). The height of nest locations ranged from 15 up to 20 m, an average of 16.8 m. All nests found on banks of the Gorki water reservoir were built on pines. Nests found on banks of thr Cheboksarskiy water reservoir were on deciduous trees. We only twice registered White-tailed Eagles nesting on platforms installed on pines. In contrast to Golden Eagles and Ospreys (Pandion haliaetus), it seems that White-tailed Eagles have not yet preferred artificial nests. The average brood size was 1.33±0,5 fledglings (n=9; range 1-2). We twice registered White-tailed Eagles wintering near nonfreezing sites of the Volga river.