Migration routes of four juvenile Imperial Eagles Aguila heliaca from the Baikal region of eastern Russia

Abstract

From 1950 to 1999 there was a substantial decrease in the number of Imperial Eagles Aquila heliaca breeding in the Baikal region of eastern Russia, but there have been no apparent changes in habitat or breeding success within this region. Identification of wintering and stopover sites is therefore necessary to discover whether negative impacts at these sites could be causing the observed population decline. To this end, we satellite-tracked four juvenile Imperial Eagles from Lake Baikal to their wintering grounds. Two sibling eagles were tracked in 1998 and two siblings from a different brood in 1999. The eagles migrated through eastern Mongolia and central Inner Mongolia (China), and wintered from south China to Thailand. Siblings independently used the same migration flyway, and the flyway was different between families. These results provide useful information for determining the causes of the decline in the population of Imperial Eagles in the Baikal region.