Europe’s breeding bird populations have shifted on average 1 kilometer north every year for the past three decades, likely driven by the climate crisis, according to one of the world’s largest citizen science projects on biodiversity.
The European Breeding Bird Atlas 2 (EBBA2) provides the most detailed picture yet of the distribution of the continent’s birds, after 120,000 volunteers and field-workers surveyed 11 million square kilometers, from the Azores in the west to the Russian Urals in the east.
The book documents changes in the range of Europe’s 539 native bird species in the 30 years since the first EBBA, which was published in 1997 but was based on observations from the 1980s. It shows that since the first study, each population can be found around 28 kilometers further north.
Mediterranean species such as the European bee-eater and little egret are now reaching the UK, France, and the Netherlands, mainly due to milder winters. Eurasian bitterns, pied avocets, and red kites have also expanded their range, probably in response to better protection of habitats coupled with laws banning persecution.
Overall, 35 percent of birds increased their breeding range, and 25 percent contracted their breeding range. (As for the rest, either they did not show any change or the trend is unknown.) Forest birds and those protected by international legislation have generally expanded their range, while farmland birds occupy a smaller total area.
Generally, if a species is present in more areas it is less likely to go extinct, but it could be spreading out because of habitat deterioration, and not because the population has increased. “The results are confirmation that the major driving forces are climate change and land-use change. At the same time, the situation is really very complex, and that’s why we will provide this data set for further exploration and investigation,” said Petr Voříšek from the Czech Society for Ornithology.
Iván Ramírez, senior head of conservation at BirdLife Europe and Central Asia, said: “Those birds that have been legally protected have been doing better than those which are not protected. This is a really important message within the European Union. We have one of the oldest policies—the Birds Directive—and we can prove that it works.” Birds protected by the Bern Convention, such as white-tailed eagles, are also doing better.
As the climate warms, forests are stretching into boreal and Arctic regions. In parts of northern Europe, there has also been tree planting (mainly for wood and paper) and land abandonment (specifically in Mediterranean areas), which have damaged farmland birds but benefited many woodland species such as woodpeckers and warblers.
Alpine species are also losing out as scrubby trees and vegetation colonize higher mountain slopes, shrinking the range of mountain grassland specialists such as wall creepers and water pipits.
Generally, farmland birds are big losers, suffering overall declines in population and reduced distribution because agricultural intensification means there is less food, such as insects and residue from harvesting. A report titled “State of Nature in the EU 2013-2018” showed 80 percent of key habitats were in poor or bad condition, and intensive farming is a major driver of decline. The UK’s farmland birds have declined by 55 percent since 1970.
If birds are forced into new habitats on the edge of their range, this can also put them under stress, particularly migratory species such as swifts and swallows, where small changes in timing have considerable implications. “Birds are optimized machines,” said Ramírez. “They have been learning for generations and millennia how to do these migrations. They have genetically been designed to do a migration of x kilometers. If you’re putting x plus 10 or 15 kilometers, you are putting them under stress.”