Bird populations across Europe are on the decline, and have been for the last 30 years, according to researchers, with the majority of losses coming from the continent's most common species.
Approximately 421 individual birds have perished in recent decades, 90 percent of them among the most common and widespread species, including house sparrows, skylarks, grey partridges and starlings.
"It is very worrying that the most common species of bird are declining rapidly because it is this group of birds that people benefit from the most," Richard Inger from the University of Exeter said in a statement.
These birds help to control agricultural pests, are important dispersers of seeds, and scavenging species play a key role in the removal of carcasses from the environment.
The good news is not all common bird species in Europe are declining. In fact, numbers of some less common birds have risen, such as great tits, robins, blue tits and blackbirds. Researchers believe this is the result of direct conservation action and legal protection in Europe.
"The study brings a very important message to conservation practice in Europe," added researcher Petr Vorisek, from the Pan-European Common Bird Monitoring Scheme (PECBMS).
After conducting research on 144 different species of European birds from many thousands of individual surveys in 25 different countries, the study authors highlight the need for better conservation efforts and wider scale environmental improvement programs, like urban green space projects and effective agri-environment schemes.
The researchers don not mention what could be causing such drastic drops in bird numbers, but possibly like hundreds of US bird species, it is the result of climate change.
"This is a warning from birds throughout Europe," noted Richard Gregory, Head of Species Monitoring and Research at the RSPB's Centre for Conservation Science. "It is clear that the way we are managing the environment is unsustainable for many of our most familiar species."
The findings were published in the journal Ecology Letters.