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Back from the dead: Rare Greater Spotted Eagles have returned to the Chernobyl area after going extinct before the accident

25 January 2021 
By Dave Rowntree
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Greater spotted eagle on the nest by Valery Dombrovski

​Scientists from the British Trust for Ornithology (BTO) have been working with scientists in Belarus to help assess how wildlife is doing in the Chernobyl Exclusion Zone (CEZ), and it seems that some species are doing very well, very well indeed.

Before the nuclear accident that occurred on 26 April 1986 at the No. 4 reactor in the Chernobyl Nuclear Power Plant, Greater Spotted Eagles were locally extinct but with the absence of human interference and the natural rewetting of a large proportion of the CEZ, the eagle is now thriving. Endangered in Europe, Greater Spotted Eagles are an indicator of wetland habitat quality and at the last count, up to thirteen pairs were breeding in the CEZ.

The Greater Spotted Eagle isn’t alone: White-tailed Eagles, also locally extinct before the accident, have also returned and are once again breeding in the area. Unlike Greater Spotted Eagles, which migrate south during winter, White-tailed Eagles are resident, and their survival during winter in the Chernobyl Exclusion Zone is likely helped by the carrion that wolves supply. As hunting is illegal in the “zone”, wolves, and other large-mammals have rebounded to abundant levels. These complex interactions between species signify the ecological recovery that is happening there without human pressures.

Valery Dombrovski, an eagle expert from Belarus, has been collecting data on birds of prey from the CEZ since 1998. Scientists analysed how the rewilding occurring in the exclusion zone has changed the species present there. They found there were winners and losers: generalist and farmland predators, which had become super-abundant since the accident, strongly declined as the open habitats (former agricultural land) rewetted or became overgrown. However, as the landscape became more waterlogged, due to collapse or blocking of drainage canals, wetland species saw an increase in abundance. Over time, the raptor composition in the CEZ became more similar to other “wild” sites in Belarus with large areas of natural habitat (mires and raised bogs) and less similar to habitats with high agricultural and plantation forest cover.

Dr Adham Ashton-Butt, lead BTO scientist on the project, said: 
“Our work shows that rewilding could be a valuable method to conserve threatened species and restore ecosystems. Rewilding, or restoration with reduced management, is becoming an increasingly employed method to deal with the global biodiversity and climate change crisis. However, long-term data on the impact of rewilding on wildlife communities are scarce or non-existent. Our dataset offers a rare exception, allowing us to show the effects on birds of prey of over thirty years of land-abandonment of previously intensively farmed area.”

There were noticeable differences in breeding raptors over the study period, while some species fluctuated after land-abandonment. Broadly, top-predators and wetland specialists, such as the Endangered Greater Spotted Eagle, increased in abundance, coinciding with an increase in wetland area as former fields became flooded due to the collapse of drainage canals.

Generalist mesopredators and farmland specialists, such as the Buzzard, and Montagu’s Harrier, which had increased beyond normal numbers - likely due to the reduction in human interference - at the beginning of the study (twelve years after the Chernobyl disaster), suffered sharp declines which levelled off after a number of years.

​Lesser Spotted Eagles, which are expanding their range into Western Europe at the expense of closely related Greater Spotted Eagles, showed continuous declines, which alongside the increase in abundance of Greater Spotted Eagle shows the opposite relationship to the national trend.
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Mire CEZ by Valery Dombrovski
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