Effects of the Russian-Kazakh frontier zone: Increased mortality of red-listed diurnal birds of prey on overhead power lines in the Orenburg Region frontier steppe

Abstract

The report focuses on rare diurnal birds of prey killed by electrocution on 6 – 10 kV hazardous overhead power lines in the Orenburg Region steppe, located in the extreme southeastern European part of the Russian Federation, on the border with Kazakhstan. Field surveys of power lines over a ten-year period indicated that 94% of rare diurnal birds of prey (steppe eagle, imperial eagle, long-legged buzzard, lesser kestrel, red-footed falcon) killed in the study area died from electrocution within a 50-km wide Russian-Kazakh frontier zone. Within that frontier area, 75% of birds died in a 25-km wide band. Statistically significant differences were found in the average values for dead birds in the distance ranges of 0 – 25 km, 25 – 50 km and > 50 km from the Russian-Kazakh border. The total number of killed birds also differed significantly among the marginal distance groups of 0 – 25 km and > 50 km. It is assumed that the increased concentration of birds of prey in the frontier zone is associated with better feeding conditions and reduced anthropogenic load, compared to other more developed and transformed areas in agricultural and technogenic terms. Complete insulation of power lines within at least the 25-km frontier zone would significantly reduce mortality of red-listed diurnal raptors on overhead power lines in the region.