Steppe Eagle’s population structure migrating through the bottleneck of Eilat in spring

Abstract

Steppe Eagles (Aquila nipalensis) migrate in large numbers past key migration flyways from almost its entire breeding region. On its spring migration route from Africa many birds fly through the bottleneck of Eilat in southern Israel. Migration timing and age structures in the population are often key elements of conservation works. In the four springs of 2015 to 2018 we systematically counted the passing Steppe Eagles at two count stations. An average of 15,039 Steppe Eagles were counted per spring. We also recorded the ages of many of the Eagles. We found patterns in the Eagle's migration that is related to the age of the eagles. Adults arrive early and are most abundant, followed by sub adults, and juveniles in timing and numbers. Furthermore, we compared our data of the structure of the passing populations with different flyways and wintering sites and found significant differences. The flyway in Eilat is mostly occupied by adult migrating birds, 72% of the aged birds were adults in the survey. The different usage of flyways by ages can be an important factor in future conservation projects.