Imperiled Eagles Are Altering Their Migration Routes to Avoid the War in Ukraine

Greater spotted eagles—large, dark brown raptors that live in Europe, Asia and Africa—are “extremely rare.” Fewer than 10,000 individuals are estimated to exist worldwide, and the International Union for Conservation of Nature classifies them as a vulnerable species with a declining population. The eagles have almost entirely disappeared from Western Europe, and now, according to a study published in Current Biology last week, they have another threat to contend with: the war in Ukraine, which is altering the birds’ migratory journeys.

Each spring, hundreds of the raptors fly north through Ukraine to their breeding grounds in southern Belarus—and researchers discovered that now, greater spotted eagles are deviating from their usual flight paths because of exposure to conflict events.

“When the conflict started in February 2022, we were kind of watching things unfold on the news like everyone else, but sitting there also with the feeling that we know our birds are about to pass through that area and wondering what that might mean for them,” Charlie Russell, the study’s lead author and an environmental scientist at the University of East Anglia in England, tells CNN’s Amarachi Orie.

Across the globe, human activity is putting migratory animals at risk. A February report from the United Nations Environment Program found that nearly half of Earth’s migratory species are facing population decline, and one in five species listed by the researchers is facing extinction. Humans have long disrupted animals’ annual migration paths by destroying habitats, building roads through migratory routes, emitting noise and light pollution and causing climate change.

Still, the impacts of war on wildlife have been more difficult for researchers to predict or track.

“On rare occasions, wild animals can benefit from human conflict,” Josh Milburn, who has researched the ethics of animals and warfare but was not involved with the new study, tells the Guardian’s Nicola Davis. “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.”

Using the GPS tracking data of 19 migrating greater spotted eagles from March and April 2022, alongside data on weather conditions and records of conflict events from the Armed Conflict Location and Event Data project, the researchers uncovered how exposure to the active war zone in Ukraine altered the eagles’ migratory routes and rest patterns.

They found that the eagles flew an average of almost 53 miles more than in previous years and strayed more from their usual paths. Females took 246 hours to complete the journey compared to 193 hours pre-conflict, while males took 181 hours to migrate compared to 125 pre-conflict.

While en route to their breeding grounds, about 30 percent of the tracked eagles made stopovers, compared to 90 percent from 2018 to 2021. Stopover sites are locations along long-distance migratory routes that provide food, water and shelter for rest and replenishment.

“These types of disturbances can have significant impacts on the behavior and potentially fitness of the eagles,” Russell says in a statement. “For individuals breeding in these areas, or other species that are less able to respond to disturbance, the impacts are likely to be much greater.”

The travel differences between sexes may be due to differing migration strategies. Before reaching Ukraine, males typically journey from wintering grounds in eastern Africa, while females migrate from Greece. “This could also impact breeding success if a disproportionate number of either sex is heavily affected by events linked to the war,” according to the statement.

Researchers worry that the conflict in Ukraine is inhibiting the eagles’ breeding and, as a result, hurting their ability to survive as a whole. Eagles that have been tired out by a longer migratory journey might delay breeding or struggle to provide for their chicks.

The study helps quantify the impacts of war on the vulnerable species, and scientists hope it will inform the eagles’ conservation post-conflict.

“Our findings show how human disturbance can inadvertently impact wildlife,” study co-author Adham Ashton-Butt, a senior research ecologist with the British Trust for Ornithology, says in the statement. “Migratory birds such as greater spotted eagles are drastically declining all over the world, and it’s imperative that we better understand and mitigate our effects on these charismatic species.”

Aaron Boorstein | READ MORE

Aaron Boorstein was an intern with Smithsonian magazine.