Differential movement of adult and juvenile Cinereous Vultures (Aegypius monachus) (Accipitriformes: Accipitridae) in Northeast Asia

Abstract

We report on differential movement of adult and juvenile cinereous vultures (Aegypius monachus) in the northeast Asia. Adult vultures remain in Mongolia throughout the year, whereas many juvenile vultures migrate from their breeding grounds in Mongolia to wintering grounds in the Republic of Korea (South Korea). We trapped adult and juvenile Cinereous Vultures in Mongolia and Korea to attach wing tags (n = 270 fledglings and 10 adults) and, for some, global positioning system telemetry units (n = 31 fledglings, 18 juveniles, and 10 adults). While adult birds never left Mongolia, fledglings and juveniles wandered more widely into Russia (rarely), China, and the Korean Peninsula. Most telemetered fledglings and juveniles for which we obtained data migrated seasonally between Mongolia and South Korea. Juvenile vultures used larger summer home ranges than adults. Juveniles used much smaller winter than summer home ranges. Over the course of the year, adult and juvenile vultures moved similar amounts that differed seasonally. How juvenile vultures learn the migration route between Mongolia and Republic of Korea remains unknown. Our results have important conservation implications, as factors influencing the survivorship of migratory birds can strongly impact populations.