Young golden eagles leave their parents' territory late

When young golden eagles spread their wings and leave their parents' territory, it's not because they've suddenly become skilled fliers, says a new study tracking 92 eagles in the Alps. Despite being able to fly proficiently just months after fledging, many young eagles remain in their parents' territory for nearly a year. Lead researcher Hester Brønnvik from the Leibniz Institute for Zoo and Wildlife Research explains that being able to fly well and actually leaving are two distinct processes.

The study, published in Royal Society Open Science, involved tagging young eagles shortly after they left the nest and monitoring their movements for up to a year. Eagles frequently traveled long distances, sometimes exceeding 77 kilometers, but often returned to their parents' territory. While their soaring skills were necessary, they didn't predict when eagles would finally leave.

Instead, the study found that eagles that ventured farther from their territory and soared higher were more likely to eventually emigrate. This suggests that factors like motivation, competition, food availability, and weather play a significant role in the decision to leave. The researchers propose that in densely populated areas like the Alpine population of golden eagles, staying in the parental territory longer may be safer than venturing into a crowded and competitive landscape.

This delay in independence, a phenomenon seen in various species with long parental care, may not be unique to eagles and could reflect a broader trend where skill acquisition doesn't necessarily predict independence.