Review of deaths and behavior of large birds of prey on power grid facilities in Tatarstan and Udmurtia (Russia), problems of modernization of 6–10 kV overhead power lines

The report analyzes the deaths of large birds of prey on power grid facilities of Tatarstan previously published in the literature since 2012 and additional ones, identified since 2019, including in the neighboring region – Udmurt Republic. Analysis of the data shows that immature Imperial Eagles (Aquila heliaca) up to 3 years old (n=11) died on the 6–10 kV power lines dangerous for birds. The percentage of fledglings that died near breeding territories after leaving their nests was 81.8% (n=9); one bird died in its second year of life and one bird died in its third year. The death of fledglings was identified in 8 breeding areas (in one of them twice), which is 3.9% of all known breeding areas of the Imperial Eagle in Tatarstan by the end of 2021 (n=205) and about 7.2% of 111 breeding areas in 16 administrative districts of southeastern Tatarstan where oil production is taking place. Two out of six fledglings, for which a time interval of death was established, died in the second half of August, and 2 eagles also died in the first and second halves of September. Distances from precisely known nests to locations where the fledglings died ranged from 0.26 to 11.7 km, 2.56 km on average (n=7). In 57.1% of cases deaths occurred at distances less than 1 km (from 260 to 600 m), and in 28.6% of cases at distances from 2 to 3 km. Observations of the behavior of imperial eagles in breeding grounds show a certain selectivity, namely avoidance of the most dangerous power lines. Adaptation of imperial eagles to the electric grid environment continues – 3 new breeding territories on the electric poles of high-voltage power lines were found. Two cases of death of immature White-Tailed Eagles (Haliaeetus albicilla) were identified on 6–10 kV power lines dangerous for birds deep in the forestland on narrow forest cleared strips in Tatarstan and Udmurtia, as well as the Steppe Eagle (Aquila nipalensis) in Udmurtia. Illegal exploitation and even construction of new 6–10 kV power lines dangerous for birds continues. Despite the measures taken to protect birds from death in the electric grid environment, the rate and quality of these measures are such that in the near future power lines will have a negative impact on eagles in the native area as they do now.