According to scientists, the use of pesticides and fertilizers in intensive farming is the main reason for the decline in the number of birds in the UK and the rest of Europe.
Compared to the last generation, 550 million fewer birds fly over the continent, and their decline is well documented. But the relative importance of different impacts on bird populations has not yet been known.
A group of more than 50 researchers, after analyzing data collected by thousands of citizen scientists in 28 countries over nearly four decades, found that intensive agriculture is primarily responsible for the decline in bird populations on the continent.
They found that the number of wild birds of all species on the continent has declined by more than a quarter since 1980, but the decline has deepened by more than half among agricultural species.
Birds that feed on invertebrates, including swifts, yellow wagtails and spotted flycatchers, have been hardest hit. “This is more than a smoking gun,” said Richard Gregory, senior researcher at the RSPB and one of the study’s lead authors.
“I don’t think the study looked at all of these factors at once, in such a sophisticated way, adjusting for one variable next to another; and it comes out with a very clear message.”
studying published in Proceedings of the National Academy of Sciencesstudied how 170 bird species have responded to four widespread human impacts, including agricultural intensification, forest cover change, urbanization and the climate crisis.
The study states that the most dramatic decline in the number of agricultural species occurred at 56.8% since the start of the studies. The number of urban birds decreased by 27.8%, and among forest birds – by 17.7%.
But in all contexts, intensive agriculture, which was on the rise across Europe, has been identified as a major factor in the decline, and the mass destruction of invertebrates as pests has created a “trophic cascade” up the food chain.
“The losses are very heavy,” Gregory said. “And many of them are reverting to such a diet of insects or association with insects, which suggests a connection with the way we farm the land.”
Urbanization, which is also on the rise across Europe, has been identified as the next most important factor putting pressure on bird populations. Gregory says many cities are steadily losing what small patches of green space they had, while modern architecture has also played a role.
“We know that many of the city’s birds – swifts, house swallows, house sparrows, starlings – that live in these conditions, that their numbers are declining very much, we think this is due to problems related to food resources, but also the construction of houses and how it is changing, how modernization is removing their natural nesting sites in these areas,” Gregory said.
Northern, cold-loving bird species have also been found to be under intense pressure, with numbers down 39.7% due to rising temperatures across Europe as a result of the climate crisis. The study notes that there were both winners and losers when temperatures changed, with numbers of southern species that prefer warmth dropping by just 17.1%.
