There are about 50 billion wild birds in the world, according to new research that uses citizen science observations to try to estimate the number of populations of nearly 10,000 species.
The paper, led by scientists at the University of New South Wales, suggests that there are around six times as many birds on the planet as humans, but that many individual species are very rare.
Four species belong to what researchers have dubbed “the billion club,” with populations estimated at over one billion. These are the house sparrow, which is found in many parts of the world, the common starling, ring-billed gull, and barn swallow.
Researchers developed estimates for 9,700 species, including penguins, emus and kookaburra, based on hundreds of millions of bird sightings recorded by birders on eBird, one of the largest citizen science projects on biodiversity in the world.
They combined the recordings with professional scientific observations to develop an algorithm that would estimate the number of populations for almost any species. The team of scientists found that there were relatively few common bird species, but a large number of rare species.
“They can be rare for natural reasons – they really only live on an island or on top of a mountain for example – or they can be rare because of human causes,” said Will Cornwell, an environmentalist at UNSW. and one of the journal’s authors. main authors.
He said that over time he hoped the models could indicate which species were in decline and where conservation efforts were needed.
Many Australian birds number in the millions. They include the Rainbow Lorikeet (19m), Sulfur-crested Cockatoo (10m) and Laughing Kookaburra (3.4m).
Sean Dooley, the National Public Affairs Officer of BirdLife Australia, is a longtime bird watcher and contributes to citizen science programs. He said the document showed the value that citizen observations can bring to scientific knowledge.
“It’s a great first step in trying to figure out what we have,” he said.
“If we can continue to do this over time, that will be the important thing because we know that we are seeing a huge loss of wildlife. Being able to come close to quantifying what’s going on is essential.
Cornwell said that by combining bird watching and professional monitoring records for bird species that had been the subject of rigorous academic studies, scientists were able to develop a model that fits some of the uncertainties that can arise from citizen science.
He said the model was then applied to birds that had not been professionally studied.
The figure of 50 billion individual birds represents the median estimate of the model produced for the total number of birds in the world.
“The whole idea came from the fact that there are a few species of birds that are really very well studied,” said Cornwell. “But there is this huge collection of citizen scientists who travel all over the world and count every bird they see.
“The really big breakthrough of this article was that we could take the science and citizen science data and then fill the void for birds that are not studied by professional scientists.”
Cornwell said there were still uncertainties in the numbers and researchers plan to refine the model as more professional research on more species occurs.
He said the research highlighted information gaps caused by the significant scientific attention given to bird species in developed regions of the globe compared to developing countries and the need to refine estimates of the world population for all species.
He said it also shows the role that citizen science can play in these efforts. Scientists will make another round of estimates in a few years.