Since time immemorial, farmlands have been as alive with bird songs as the sound of the wind. But now, these melodies are falling silent. For the last forty years, bird species that live in and among farmlands have plummeted worldwide, a downward spiral researchers say has flown under the public's radar.

“There's either large, charismatic animals [that] everybody knows are disappearing, or unknown species that vanish without being noticed—but what of the fate of the common species that are also disappearing without warning?” asks Benoît Fontaine, a conservation biologist at France's National Museum of Natural History.

In March, Fontaine and his colleagues announced the results of a survey of France's bird populations. The findings, which grabbed headlines around the world, were grim; since 1989, France's farmland bird populations have shrunk by a third.

The catastrophic decline of France’s farmland birds RELATIVE ABUNDANCE OF COMMON BIRDS IN FRANCE (1989 = 1.0) GENERALIST BIRDS (14) 1.2 1.0 WOODLAND BIRDS (24) 0.8 URBAN BIRDS (13) FARMLAND BIRDS (24 species) 0.6 Since 1989, France’s common farmland birds have declined by 33 percent—a wipeout that’s “approaching an ecological catastrophe,” according to the 2017 results of a long-term national monitoring survey. In 2016 and 2017, the birds’ decline quickened, leading some experts to fear that “silent springs” will soon strike France’s cultivated plains. 0.4 0.2 0 1989 1993 1997 2001* 2005 2009 2013 2017 *Sampling methods changed in 2001 to improve accuracy SOURCE: French National Museum of Natural History The catastrophic decline of France’s farmland birds RELATIVE ABUNDANCE OF COMMON BIRDS IN FRANCE (1989 = 1.0) GENERALIST BIRDS (14) 1.2 19% increase 1.0 WOODLAND BIRDS (24) 3% decline URBAN BIRDS (13) 0.8 30% decline 0.6 FARMLAND BIRDS (24 species) Since 1989, France’s common farmland birds have declined by 33 percent—a wipeout that’s “approaching an ecological catastrophe,” according to the 2017 results of a long-term national monitoring survey. In 2016 and 2017, the birds’ decline quickened, leading some experts to fear that “silent springs” will soon strike France’s cultivated plains. 0.4 0.2 0 1989 1993 1997 2001* 2005 2009 2013 2017 *Sampling methods changed in 2001 to improve accuracy SOURCE: French National Museum of Natural History The catastrophic decline of France’s farmland birds RELATIVE ABUNDANCE OF COMMON BIRDS IN FRANCE (1989 = 1.0) GENERALIST BIRDS (14) 1.2 19% increase 1.0 WOODLAND BIRDS (24) 3% decline URBAN BIRDS (13) 0.8 30% decline FARMLAND BIRDS (24 species) 0.6 Since 1989, France’s common farmland birds have declined by 33 percent—a wipeout that’s “approaching an ecological catastrophe,” according to the 2017 results of a long-term national monitoring survey. In 2016 and 2017, the birds’ decline quickened, leading some experts to fear that “silent springs” will soon strike France’s cultivated plains. 0.4 0.2 0 1989 1993 1997 2001* 2005 2009 2013 2017 *Sampling methods changed in 2001 to improve accuracy SOURCE: French National Museum of Natural History

Zoom in to the local level, and the findings grow more alarming. Across France, birds well-adapted to human environments are on the upswing. But in the farmland of France's Deux-Sèvres region, these generalists are also in freefall, with some species down by 85 percent since 2009. Researchers take this decline as a sign of the ecosystem's poor health.

Down on the farm, birds of all kinds are vanishing To see what France’s bird meltdown looks like up close, the National Center for Scientific Research recently studied cereal plains in western France’s Deux-Sèvres region. Not only were the area's agricultural-specialist birds shrinking in numbers, but generalist birds were too—a joint decline that experts link to intensified land use and pesticides. AVERAGE NUMBER OF MALE BIRDS PER square mile (from 160 locations, 2017) 30 15 7.5 Ground-nesting birds are victims to intensive mechanical work, which reduces nesting cover and chick food on farms. population DECLINE (2009 to 2017) 0% 15% 20% Eurasian skylark 40% The switch to taller, fall-sown cereals pushed the birds' nests into more vulnerable areas. 60% 72% 86% decline 80% Little bustard Red-legged partridge 100% Habitat fragmentation and hunting have chipped away at the native bird’s numbers. Birds in hedges alongside disrupted farms have also seen losses, as pesticides kill off the insects they eat. 0% 20% 40% 60% 60% 80% 90% decline 84% Common whitethroat Cirl bunting 100% Yellowhammer Pesticides and herbicides killed off insects and seed-rich patches of weeds. Generalist birds still have habitats, yet they’re also declining—suggesting that the ecosystem’s overall health is degrading. 0% 20% 40% 52% 54% 60% 85% decline Eurasian blackcap Common nightingale 80% European turtle dove Even common birds well adapted to human activity have seen declines. 100% SOURCE: Vincent Bretagnolle, Long-Term Socio-Ecological Research Zone Atelier Plaine & Val de Sèvre, CNRS, France Down on the farm, birds of all kinds are vanishing 30 To see what France’s bird meltdown looks like up close, the National Center for Scientific Research recently studied cereal plains in western France’s Deux-Sèvres region. Not only were the area’s agricultural-specialist birds shrinking in numbers, but generalist birds were too—a joint decline that experts link to intensified land use and pesticides. AVERAGE NUMBER OF MALE BIRDS PER square mile (from 160 locations, 2017) 15 7.5 Ground-nesting birds are victims to intensive mechanical work, which reduces nesting cover and chick food on farms. Birds in hedges alongside disrupted farms have also seen losses, as pesticides kill off the insects they eat. Generalist birds still have habitats, yet they’re also declining—suggesting that the ecosystem’s overall health is degrading. Bird population DECLINE from 2009 to 2017 0% 15% 20% Eurasian skylark 40% 52% 54% The switch to taller, fall-sown cereals pushed the birds' nests into more vulnerable areas. 60% 60% 72% 86% decline Eurasian blackcap Common nightingale 84% 85% Common whitethroat 80% Little bustard 90% Cirl bunting European turtle dove Even common birds well adapted to human activity have seen declines. Red-legged partridge 100% Yellowhammer Habitat fragmentation and hunting have chipped away at the native bird’s numbers. Pesticides and herbicides killed off insects and seed-rich patches of weeds. SOURCE: Vincent Bretagnolle, Long-Term Socio-Ecological Research Zone Atelier Plaine & Val de Sèvre, CNRS, France

“The Silent Spring that Rachel Carson warned of could become a reality unless we act very quickly,” said Center for Biological Studies ecologist Vincent Bretagnolle, who led the local study, in a statement.

“This is a very important story to communicate, although it is not a new story,” said Ian Burfield, the global science coordinator for BirdLife International, in an email to National Geographic.

Why are these birds vanishing?

Long before the dawn of agriculture, some birds adapted to living in open environments such as grasslands. As these landscapes bent to humans' will, the birds followed suit, building their nests in hedgerows and eating croplands' insects and seeds.

But since the 1960s, agriculture's “green revolution” has dramatically reshaped how we grow food. In the industrialized world, croplands have transformed into mechanically sculpted monocultures, nourished with fertilizers and protected with herbicides and insecticides.

This shift staved off fears of global starvation, tripling agricultural output even as humans doubled in number. But for birds, this brave new world of intensification has meant death by a million pinpricks. Non-crop areas where birds once nested are now inhospitable fields of corn or wheat; mechanized mowing has injured birds or mangled their nests.

Insecticides are also thought to slash farmland birds' food supplies. In 2014, Dutch researchers found that use of the insecticide imidacloprid correlated with declines of Dutch bug-eating birds. Three years later, researchers announced that from 1989 to 2016, Germany had lost three quarters of its flying insects by mass—a nosedive tentatively connected with modern agriculture.

“When I was a kid, we spent our holidays crossing France with a car, [and] after the trip, we had to clean the windshield, because it was full of pieces of insects that had crashed,” says Fontaine. “Now, that’s no longer the case. It’s clean after the whole trip.”

Scientists consider this vanishing dire. On Thursday, 233 researchers from around the world published a joint letter in Science calling for restrictions on neonicotinoids, a class of insecticides widely used in agriculture.

How do we fix it?

Among threatened birds living today, agriculture in its present form poses the single biggest extinction threat, according to BirdLife's 2018 State of the World's Birds report. So to spur the birds’ rebound, researchers say that farming practices must change radically to become more sustainable. There are no easy fixes.

Agriculture is the leading risk for threatened birds * Most of the forces threatening bird populations are generated by humans, at least in part. Currently, expanding agriculture and aquaculture pose the greatest risks; in the future the leading risk factor for many birds may be climate change. Agriculture and aquaculture Logging Hunting and trapping Invasive species Industry and urbanization Climate change and severe weather Pollution Geological events (Includes human disturbances, mining, fires) Other 0% 25% 50% of species affected SOURCE: BirdLife International Agriculture is the leading risk for threatened birds * Most of the forces threatening bird populations are generated by humans, at least in part. Currently, expanding agriculture and aquaculture pose the greatest risks; in the future the leading risk factor for many birds may be climate change. Agriculture and aquaculture Logging Hunting and trapping Invasive species Industry and urbanization Climate change and severe weather Pollution Geological events Other 25% 50% of species affected 0% (Includes human disturbances, mining, fires) SOURCE: BirdLife International Agriculture is the leading risk for threatened birds * Most of the forces threatening bird populations are generated by humans, at least in part. Currently, expanding agriculture and aquaculture pose the greatest risks; in the future the leading risk factor for many birds may be climate change. Agriculture and aquaculture Logging Hunting and trapping Invasive species Industry and urbanization Climate change and severe weather Pollution Geological events Other 0% 25% 50% of species affected (Includes human disturbances, mining, fires) SOURCE: BirdLife International

“People are looking for simple solutions: 'Oh, this pesticide is toxic, let’s swap it out for another one.' I see that as a dead end,” says Christy Morrissey, a University of Saskatchewan ecologist who studies pesticides' effects on North American birds and co-signed the neonicotinoids letter.

“It’s not about one pesticide being a problem,” she adds. “It's that they’re a symptom of a bigger problem: the complete and utter dependence on chemical inputs.”

At projects across the world, researchers and farmers are working together to craft a new “agroecological” future. Test farms in the U.S., Canada, and the U.K. are diversifying their plots and building natural refuges for local birds. Morrissey is assembling a network of Canadian researchers to develop new ways to monitor farms' soil health, water quality, and biodiversity.

Some initiatives also address farmers' economic concerns. Fontaine points to one recent pilot project in Italy that provided insurance to farmers who were willing to forego pesticides. Not only did farmers' businesses stay steady, but yields didn't drop much either.

“[Farmers] are not the bad guys. If they can do farming in a way that is better for biodiversity, of course they're willing to do that,” says Fontaine. “Plus, they're the ones who really know the field, and they're in the best place to make the changes.”

That said, Fontaine admits that change hasn't come easy. In March, when Fontaine's team announced its survey's grim results, even sympathetic farmers lamented that their hard work had been for naught.

“What they do is visible at the very small scale, [but] changes have to be done on a much larger scale,” says Fontaine.