Electrocution of Steppe Eagles and Golden Eagles in Mongolia

We examined the spatial and temporal distribution of Steppe Eagle (Aquila nipalensis) and Golden Eagle (Aquila chrysaetos) electrocutions at power distribution lines in Mongolia from 2013 through 2015. Steppe Eagles were electrocuted most frequently during the summer in the steppe zone of Mongolia, coinciding with their occurrence as summer breeding visitors. In contrast, Golden Eagles were electrocuted mainly during the winter, when birds dispersed from their mountain or northern breeding areas and overwintered in open steppe landscapes. Eagles were more likely to be electrocuted at the crossarm than at the pole top. Pre-existing mitigation methods at power lines in Mongolia, comprising grounded metal perch deflectors and deterrents placed centrally on crossarms between the pole and pin insulator, did not significantly reduce electrocution rates for eagle species compared to unmitigated crossarms. We recorded an exceptionally high electrocution rate involving 22 Golden Eagles at one 98-km-long power line, possibly because of high prey abundance in the vicinity. The electrocution risk faced by eagles in Mongolia has diminished in recent years, because a nationwide program to insulate dangerous distribution lines was implemented in 2019–2022, and because the Mongolian government amended the national standard relating to distribution lines in September 2021 to include bird safety. Despite this progress, compliance needs to be enforced as dangerous lines continue to be constructed.