Have eagles changed their migration routes due to war? Let’s find out with Ukrainian ornithologists

Recently, Ukrainian journalists reported that Russia's full-scale war against Ukraine has affected bird migration. The news story was based on a study published in Current Biology, a biology journal. The research claims that some eagles flew an average of 85 kilometers more during migration in 2022 than usual, which extended their migration time by 55 hours.

The news seemed shocking, and many media outlets picked it up but missed some crucial details. We're here to delve into the specifics and find out what's really happening with the birds during the war in Ukraine. Spoiler alert: it's not just the war affecting their migration routes, behavior, and nesting choices. Other human-made dangers can be encountered anywhere.

What the published research actually says

The research focuses on a relatively small number of greater spotted eagles from the Ukrainian northwestern region of Polissia, who were moving west during migration, avoiding areas with active combat. Scientists also compared migration paths from years before Russia's full-out invasion only with 2022 and provided no data for the subsequent war year 2023.

Other scientists criticized the publication. Some believe the data is insufficient, while others argue that the war doesn't significantly impact bird migration routes, at least not the eagles. One of these scientists is ornithologist Stanislav Viter, who holds a PhD in biology.

"Polissia's eagles do not fly over combat zones! They never did, as their migration routes lie along the Carpathian Mountains, through Podillia [west-central and southwestern parts of Ukraine], and then through the Eastern Balkans. So, the fighting has nothing to do with it," says Viter. 

However, civil aviation traffic as one of their navigation markers could have caused some changes in migration—the Ukrainian airspace was closed for planes on February 24, 2022, when Russia unleashed its full-scale war. The scientist argues that the shift in migration routes was short-term. The leading factor for these changes wasn't the explosions but the loss of other navigation markers. 

"In 2022, I observed the same thing on the Siverskyi Donets River [in Ukraine's east], but by 2023, I saw a noticeable migration even over or near combat zones. Nesting of species like the common buzzard, honey buzzard, white-tailed eagle, black kite, and booted eagle within 20 kilometers of the front line remained intact," Sviatoslav Viter says.

The scientist also argued in his social media post that the migration route changed in 2022, and the changes lasted only for one season.

"[The changes] didn't happen because of the fighting or explosions, as migrating birds of prey are indifferent to these explosions. They even visit battlefields to feast on fresh human flesh," says Stanislav Viter. "The changes in migration routes in 2022 were due to the loss of one of their navigation markers, namely the established routes of civil aviation in Ukraine and nearby areas in Russia. This caused the migration route distortions for one season. By the fall of 2023, large eagles were flying through the war-torn Kharkiv region and stopping in the suburbs near the village of Khorosheve, where locals hear explosions constantly!" 

What else could affect bird behavior?

Vitalii Hryshchenko, Deputy Director for scientific work at the Kaniv Nature Reserve of Taras Shevchenko National University of Kyiv, says white storks arrived in Ukraine significantly later in 2022 than usual. However, this was not caused by the hostilities but by the cold weather along their migration routes.

"A severe cold snap in Turkey caused the birds to get 'stuck' before crossing the Bosporus. This might have also affected the eagles," the scientist speculates.

Birds suffer during war and in peacetime

A black kite with a transmitter, whose behavior Czech scientist Ivan Literák has studied since 2019, did not start breeding in its nesting site in the village of Dvorichna in the northeastern Kharkiv region in the summer of 2022. At that time, Dvorichna was occupied by Russian forces, and now the front line is just a few kilometers away from the village.

Stanislav Viter comments that birds do not nest in combat zones 20-30 km wide or in areas of scorched earth. If their habitat disappears, they have nowhere to nest, raise their young, and find food. Any interference, whether a fire caused by fighting or selective logging in forests, affects bird behavior.

We need to pay attention to not only the front-line areas but also the entire territory of Ukraine, hiding many more threats to birds.

"I suggest focusing more on the destruction of raptors' habitats by forest fires caused by hostilities, such as in the Serebrianske Forestry in the Luhansk region. We also should consider the destruction of predatory bird habitats in peacetime before Russia's full-out invasion when domestic land users destroyed nesting areas of birds of prey far more than the artillery fire of both the Ukrainian Armed Forces and Russian forces combined, at least in the Kharkiv region," Viter stresses.

What do we know about the impact of other wars on birds?

The full-scale war has been ongoing for two years, while the war in Ukraine's east has continued for ten years. This time is long for human life but too short for research. The short duration makes it too early to draw conclusions about how modern warfare affects bird migration.

However, we found other studies, such as those by Sir Hugh Gladstone, a Scottish landowner who wrote a book about the impact of the First World War on birds from 1914 to 1918.

Although bird life was described as almost normal in artillery zones and near trenches, many species were likely driven out of areas destroyed by shelling. However, the impact on bird life, as far as can be judged, was minimal, and birds in the most heavily shelled areas showed a remarkable ability to adapt to conditions that would have been considered impossible before the war. The studies mention that birds adapted to loud explosions and were indifferent to the noise of battle.

Gladstone dedicated a separate chapter to the impact of war on migration. The data is vague and cannot be scientifically evaluated, but the Scottish scientist mentions minor changes in migration routes. Some birds chose new flight routes, did not return from wintering grounds, or selected new regions for nesting and raising their young. The author writes that in 1915, many different birds, especially those species that migrate through the Carpathians, were observed in Tavria Governorate (now Crimea, parts of Kherson, and Zaporizhzhia regions in Ukraine).

"Those birds whose nests were usually located in areas affected by the war were forced to migrate. Birds had to leave their homes and migrate to other places, leading to increased flights of certain bird species to specific locations," the study states.

The researcher also argues that 60 species of migratory birds stopped visiting Great Britain due to shelling, but this claim was soon disputed. The book presents many interesting observations, although they were collected from eyewitnesses, leaving a high probability of errors. The author concluded the chapter on migration by stating that there is still much potential for further research.

No to premature conclusions 

We can only settle the debates among ornithologists and provide definitive conclusions after the war.

"In general, we can't say that birds are avoiding Ukraine during migration or that there's a significant decrease in the number of birds. The scale of the war isn't enough to deter birds from migrating. Some birds avoid the area, while others continue to fly through—it's all very individual," says Stanislav Viter.

He says many factors, like weather conditions and food distribution, can influence bird migration.

"We don't have enough data, and the impact on birds is very localized, within a very narrow strip," Viter adds.

Restoring destroyed areas after war

We can help birds restore their homes where their habitats have been destroyed. For instance, the Kreminna Forest Hunting Reserve, which includes the burnt Serebrianske Forestry, can be restored. Stanislav Viter suggested this plan:

"First, we should cut down the burnt pines, plant new ones, and leave the undamaged areas as they are. The birds will return over time. The Serebriansky Forest impacts a few pairs of birds so they can nest in nearby places. The damaged area is limited, and the harm is local," says Viter.

Protecting undamaged areas

Ukraine can also conserve new areas. If some bird habitats were destroyed, other areas not yet affected by human activity could become new homes for birds. It's crucial to protect the remaining natural habitats.

According to biologist Oleksii Vasyliuk, head of the Ukrainian Nature Conservation Group, new protected areas will significantly improve conditions for biodiversity. These areas can compensate for the loss of wildlife during the full-scale war.

Rather than just saving the last remnants, restoring natural ecosystems where they once were is the modern foundation for sustainable development in Europe. In recent years, European countries have increasingly made bold and forward-thinking decisions to stop global climate change and ensure a secure future for the entire continent.