White-Tailed Eagle in the Republic of Tatarstan
Authors:   Kazan Federal University, Elabuga Institute, National Park “Nizhnyaya Kama”, Bekmansurov R.H. , Bekmansurova N.V. ,   Municipal budgetary institution of additional education, the Center for Children and Youth Tourism and Excursions “Yuldash”, Kostin E.S. ,   State Natural Reserve of complex profile “Spassky”, Gorshkov Yu.A. ,   Volzhsko-Kamsky State Nature Reserve, Karyakin I.V. ,   Russian Raptor Research and Conservation Network; Sibecocenter LLC
Published: October 2023

The White-Tailed Eagle (Haliaeetus albicilla) has been a key species for projects on study and conservation of large raptors in Tatarstan, which has been continuously carried out since 2011. The main monitoring studies were carried out in the upper part of Kuibyshev and Nizhnekamsk reservoirs, where large population groups have been formed since the end of the 20th century. Protected areas were the main monitoring plots. Currently, the section “Raptors of the World” of the web GIS “Faunistics” contains data on 210 White-Tailed Eagle breeding territories in Tatarstan. Research in the 20th and 21st centuries formed the basis (about 23%) of this database (Karyakin, 1992; 1994; 1997; Barabashin et al., 2002; Korepov, 2004; Pavlov, 2005; Korepov, 2006; Nikolenko, 2006; Korepov et al., 2013). But about 3% of the territories that were identified during this period have been empty for a long time, as breeding territories and nests were not found there over the past 13–15 years of observations. Remaining breeding territories were identified after 2010, and most of them we classify as occupied by White-Tailed Eagle. On some of them, there was a change of nests and, accordingly, displacement of breeding territories, and the number of breeding pairs varied in different years on some monitoring plots, even in protected areas, such as Volga-Kama Nature Reserve and “Nizhnyaya Kama” National Park. This may be due to the conditions of a particular season, and, in part, the long formation of new pairs after bird deaths. The frequent change of nests that were located near the former breeding territories is probably also associated with the change of birds in a pair. In general, the tendency of successful breeding on no more than 50% of breeding territories continues in recent years. There are no changes in fertility rates, with broods stable at 1–3 nestlings. Additionally, calculations were carried out to determine the start of egg laying based on determining the nestling age, mainly by the wing length (Helander, 1981) and deduction of the average incubation period of 37 days. The timing of egg laying for 2018–2023, just as for 2011–2016 (Bekmansurov, 2019), maintained a wide range from February 23 to April 3, but the peak of egg laying shifted from the first half of March to its second part. We used a smaller sample in calculations (n=65, 55% of the previous sample), which may affect overall results and conclusions. Nevertheless, the shift in main timing of egg laying could be associated with change in wintering conditions in and near White-Tailed Eagle natal area, since observations have shown that in winter, many territorial individuals did not move from breeding territories far and for a long time. To level out errors in calculations, we divided indicators into groups, and the March indicators were divided into 6 groups by 5 calendar days. Yet a common error is found in both old and new data, associated with the incubation period of 37 days. Thus, a video camera installed in White-Tailed Eagle nest showed that the incubation period for a single egg this season was 35 days, with it being laid on the night of March 24–25 and hatching on the night of April 28–29. It is unknown exactly how many pairs have differences in egg incubation time, but it is likely that an adjustment of an incubation period is necessary to level the calculations of breeding dates. We continued to ring nestlings, but in smaller numbers than previously, and mainly on more accessible nests. We are yet to receive direct evidence that ringed birds have bred, but photographic observations of ringed adult birds in the natal region suggest their nesting. 14 nestlings were tagged with trackers in Volga-Kama Nature Reserve and “Nizhnyaya Kama” National Park before leaving the nests (five nestlings in 2018, four in 2019, four in 2021, one in 2022). They confirmed the general southwestern direction of migration that was previously identified by colored tags and specified the wintering sites in an area between the Middle and Lower Volga, Lower reaches of Don and water reservoirs in Ukraine. Wintering sites in Kazakhstan and Trans Urals were identified as well. Five birds moved to wintering sites for over 1000 km (1360 km maximum). Two birds moved to the closest wintering sites, 285 and 508 km away. Two birds demonstrated the maximum territorial connections with distances of 1860 and 1890 km between the extreme points of wintering sites and further migrations. Of the birds tracked during the first autumn migration, three (21.4%) dropped out of study, two of them died at a distance of 610, 1009 km from the nests, and one bird was found sick at a distance of 501 km. One bird (7.14%) died during the second autumn migration 508 km away, another (7.14%) died during the third wintering at a distance of about 1080 km from the nest. The reasons for the death of these birds remain unknown. One bird died from a gunshot wound after return from the third wintering near the natal area at a distance of about 250 km from the nest. Contact with two birds (14.28%) was lost, possibly due to a tracker malfunction. Currently, tracking is carried out for three birds born in 2018, one – in 2021, one – in 2022. None of the three five-year old birds took part in breeding, but all of them lived in the natal region during the breeding season. Modernization of bird-hazardous overhead power lines continues in Tatarstan. Modernization program focuses on ensuring the protection of birds from electric shock, not only in nesting areas, but also near rural areas, where birds are concentrated around rural settlements, livestock farms, grain flows, and especially in places where meat products are disposed of, which attract White-Tailed Eagle in winter. In recent years, it was planned to build a complex of wind power plants in Tatarstan, at least at five sites located off the banks of the Kama and Volga, near the concentration of White-Tailed Eagle breeding territories. We hope that arguments for moving construction sites to safer places will be taken into account, as well as the need for more bird-friendly wind turbine technologies.