GPS tracking showed that greater spotted eagles made significant detours and reduced or skipped rest stops after the invasion, leading to longer and more energy-intensive journeys to their breeding grounds.
Charlie Russell, a study co-author from the University of East Anglia, likened this to running a marathon without water breaks and then being asked to run additional miles.
“It’s kind of like if you were to run a marathon but you had no water breaks. And at the end, someone asks you to run an extra seven or eight miles,” he said.
The researchers warned that this could delay breeding as the eagles would need more time to recover, potentially impacting the survival of their young due to reduced prey availability at hatching time.
In their paper published in Current Biology, Russell and his team analyzed the migration routes of 19 greater spotted eagles traveling through Ukraine to southern Belarus in March and April 2022, shortly after the Russian invasion. They compared these routes to 65 migrations recorded by 20 birds between 2018 and 2021.
The study found that the eagles traveled an average of 85 km (53 miles) further after the invasion, with one eagle adding 249 km (155 miles) to its journey. The trips took an average of 55 hours longer, and males had a lower flight speed; whereas 90% of eagles made stopovers in Ukraine before the conflict, only 32% did so afterwards, with some areas being completely avoided due to high military activity.
The greatest deviations from the direct path were observed in areas with heightened military activity.
Josh Milburn from Loughborough University noted that the study highlights the negative impacts of war on wild animals, reflecting similar findings from other conflict zones regarding both conservation and the suffering of individual animals.
“On rare occasions, wild animals can benefit from human conflict,” he said. “But the findings of this study echo what we know from previous research focused on other war zones: war has an overwhelmingly negative impact on wild animals, both in terms of conservation goals and in terms of the suffering of individual animals,” he added.
