Bird populations in France have decreased by a third over the last 15 years, according to researchers who sounded the alarm on March 20. The birds are reportedly starving to death.

“The situation is catastrophic,” said Benoit Fontaine, a conservation biologist at France’s National Museum of Natural History and co-author of one of two studies – one national and the other covering a large region in central France.

“Our countryside is in the process of become a veritable desert,” said Fontaine in a statement released by the National Centre for Scientific Research (CNRS), which also contributed to the findings.

As reported by the Agence France-Presse (AFP), the common white throat, the ortolan bunting, the Eurasian skylark and other once-ubiquitous species have all fallen off by at least a third. A migratory song bird, the meadow pipit, has declined by nearly 70%.

Researchers think the intensive use of pesticides on vast tracts of monoculture crops, especially wheat and corn, is to blame. They explained the problem is not that birds are being poisoned, but that the insects on which they depend for food have disappeared.

“There are hardly any insects left, that’s the number one problem,” said Vincent Bretagnolle, a CNRS ecologist at the Centre for Biological Studies in Chize.

He noted that recent research has uncovered similar trends across Europe, estimating that flying insects have declined by 80%, and bird populations have dropped by more than 400m in 30 years.

In France, the two studies also blame industrial-scale agriculture.

“What is really alarming, is that all the birds in an agricultural setting are declining at the same speed, even ‘generalist’ birds,” which also thrive in other settings such as wooded areas, said Bretagnolle.

“That shows that the overall quality of the agricultural ecosystem is deteriorating”.