Nesting biology of white-tailed eagles (Haliaeetus albicilla) at the nest building stage in “Sengileevskiye gory” national park 

Mikhail V. Korepov, Candidate of biological sciences, associate professor of the sub-department of biology and chemistry, Ulyanovsk State Pedagogical University named after I.N. Ulyanov (4/5 Lenina square, Ulyanovsk, Russia); head of the department of science, “Sengileevskiye Gory” National park (1a Sadovaya street, Sengiley, Ulyanovsk region, Russia), E-mail: korepov@list.ru
Dar'ya A. Nikolaeva, Master’s degree student, Ulyanovsk State Pedagogical University named after I.N. Ulyanov (4/5 Lenina square, Ulyanovsk, Russia), E-mail: nikolaewadaria@gmail.com
Stanislav A. Stryukov, Candidate of biological sciences, head of the sector of paleontology, Ulyanovsk Regional Museum of Local Lore named after I.A. Goncharov (3/4 Noviy Venets boulevard, Ulyanovsk, Russia), E-mail: stanislav_str@mail.ru
Pavel O. Pavlov, Postgraduate student, Ulyanovsk State Pedagogical University named after I.N. Ulyanov (4/5 Lenina square, Ulyanovsk, Russia); researcher of the department of science, “Sengileevskiye Gory” National park (1a Sadovaya street, Sengiley, Ulyanovsk region, Russia); junior researcher of the department of nature, Ulyanovsk Regional Museum of Local Lore named after I.A. Goncharov (3/4 Noviy Venets boulevard, Ulyanovsk, Russia), E-mail: pavelmml@mail.ru
Irina P. Aryulina, Weather forecaster, Ulyanovsk Center for Hydrometeorology and Environmental Monitoring – branch of Volga Department for Hydrometeorology and Environmental Monitoring (32 Goncharova street, Ulyanovsk, Russia), E-mail: arulin55@gmail.com
Mariya N. Golubeva, Postgraduate student, Ulyanovsk State Pedagogical University named after I.N. Ulyanov (4/5 Lenina square, Ulyanovsk, Russia), E-mail: golybevamaha2021@yandex.ru 

Background. The white-tailed eagle (Haliaeetus albicilla) is a rare and vulnerable predator of Ulyanovsk region. The article presents original materials on the nesting biology of the species in the winter-spring period in the conditions of the breeding site, collected on the territory of “Sengileevskiye gory” national park. Materials and methods. To collect the material, an autonomous video surveillance system was used, installed over a perennial nest of white-tailed eagles. The observations continued from December 13, 2020 to April 24, 2021. Results. Demonstrative activity at the nest of white-tailed eagles began in the third decade of January. Active nest building began in the first decade of March. During the second decade of March, the birds began to imitate brooding. The male was the most active during the nest building period. The forage diet in the winterspring period consists of 5 species of vertebrates, among which fish predominates. Conclusions. The male plays the key role in initiating reproduction. Demonstrative nesting begins at the height of winter, active nest building in early spring. Imitation of incubation of clutches is most likely a manifestation of the protection of the nesting site under conditions of intraspecific competition. 

white-tailed eagle, Haliaeetus albicilla, breeding biology, Sengileevskie gory National Park 

Korepov M.V., Nikolaeva D.A., Stryukov S.A., Pavlov P.O., Aryulina I.P., Golubeva M.N. Nesting biology of white-tailed eagles (Haliaeetus albicilla) at the nest building stage in “Sengileevskiye gory” national park. Izvestiya vysshikh uchebnykh zavedeniy. Povolzhskiy region. Estestvennye nauki = University proceedings. Volga region. Natural sciences. 2022;(4):95–106. (In Russ.). doi:10.21685/2307-9150-2022-4-9