How many birds are there in the world? Over 600,000 citizen scientists helped find out –

How many birds are there in the world? Over 600,000 citizen scientists helped find out – fr

TORONTO – In a monumental effort, Australian researchers have attempted to estimate the number of birds in the world using observational data from more than 600,000 citizen scientists.

According to the study, published Tuesday in the Proceedings of the National Academy of Sciences, there are about 50 billion individual birds in the world – or about six birds for every human on the planet.

“Humans have put a lot of effort into counting the members of our own species – all 7.8 billion of us,” said Will Cornwell, University of New South Wales Science ecologist and co-lead author. of the study, in a press release. .

“This is the first global effort to count a series of other species.”

As for bird species, the UNSW study found that there were around 9,700 different species, including flightless birds, such as emus and penguins.

Of these species, only four had the distinct honor of being part of what researchers dubbed “the billion club,” meaning they had an estimated global population of over one billion. These species included the house sparrow (1.6 billion), European starlings (1.3 billion), ring-billed gulls (1.2 billion) and barn swallows (1.1 billion).

“It was surprising that only a few species dominate the total number of individual birds in the world,” said lead author of the study, Corey Callaghan, who completed the research while a postdoctoral researcher at UNSW Science. .

“What made these species so evolutionarily successful?”

The dataset for the study included records for almost all bird species (92 percent) currently alive. The remaining eight percent, the researchers said, were excluded because they were so rare that there was a lack of data available about them.

In order to calculate these population estimates, the researchers used nearly a billion bird sightings recorded by birders between 2010 and 2019 on the eBird online database, one of the largest science projects related to it. to the world’s biodiversity, managed by the Cornell Lab of Ornithology.

They combined this data with detailed case studies and developed an algorithm to estimate the actual global population of each bird species. This calculation also took into account the “detectability” of each species – that is, the likelihood that the bird was spotted by someone and registered on eBird, the researchers said.

“Although this study focuses on birds, our large-scale data integration approach could serve as a model for calculating species-specific abundances for other groups of animals,” Corey Callaghan, who is now based at the German Center for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, said.

Why did these researchers find it important to estimate the world’s bird population? Callaghan said it was a critical first step in conservation.

“By properly counting what is out there, we learn which species might be vulnerable and can track how those patterns change over time – in other words, we can better understand our benchmarks,” he said.

And although 50 billion is a lot of birds, not all species thrive as well as those in the “billion club,” scientists have warned. Some species, including the Chinese crested tern, the noisy scrub bird, and the invisible rail, have global populations estimated at less than 5,000.

“We’ll be able to tell how these species are doing by repeating the study in five or 10 years,” said Cornwell. “If the number of their populations decreases, it could be a real wake-up call for the health of our ecosystem. ”


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