Eagles that have migratory routes through Ukraine have shifted their flight paths to avoid areas affected by the conflict, researchers have found.
GPS data has revealed that greater spotted eagles not only made large detours after the invasion began, but also curtailed pitstops to rest and refuel, or avoided making them altogether.
The upshot, the team say, is that the vulnerable raptors took longer to reach their breeding grounds, and probably expended more energy to get there.
“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,” said Charlie Russell of the University of East Anglia, a co-author of the study.
The researchers warned the situation could delay breeding, as the eagles could need longer to recuperate, and affect the survival chances of any young, as prey may be less available when the eggs hatch.
Writing in the journal Current Biology, Russell and colleagues reported how they analysed migration routes taken by 19 greater spotted eagles as they flew through Ukraine to breeding grounds in southern Belarus in March and April 2022 – just weeks after the Russian invasion of Ukraine began. While females travel from overwintering grounds in Greece, males travel from sites in east Africa.
The researchers compared these paths with 65 migrations recorded from 20 birds in 2018-21.
The findings suggest the eagles travelled an extra 53 miles (85km) on average after the invasion. Russell said one eagle added an extra 155 miles to its route.
The journey took, on average, 55 hours longer after the conflict started, with males found to have a lower flight speed than before the conflict began.
And while 90% of eagles made stopovers in Ukraine before the conflict, only 32% did so after the invasion, with some sites avoided altogether.
The team said the greatest deviations from a direct path occurred where military activity was higher. However, Russell said, the degree to which the eagles appeared to have been affected varied.
Indeed while one eagle, nicknamed Borovets, continued to fly via Kyiv despite intense fighting, another – known as Denisa – shifted its path after flying within a kilometre of explosions and battles around the outskirts of the city.
Russell said the detours appeared to have been made on the fly in response to sporadic events.
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“It is not like the birds are checking the news every morning to figure out where they should or shouldn’t fly on their migrations,” he said.
Russell said the results may underestimate the impact of the conflict, given some eagles could also be exposed to such stresses during the breeding period itself.
“Right now, there is not much that we can do, but it’s important that we are understanding the stresses on these populations, so that in a post-conflict scenario we can help to not just support greater spotted eagle populations and help them recover, but ecosystems as a whole,” he added.
Dr Josh Milburn, a philosopher at Loughborough University whose research explores ethical questions about animals and warfare, said the study expanded on what is already known about the negative effects of the conflict on Ukraine’s domesticated and captive wild 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.”
