by Elizabeth Gamillo/Smithsonianmag.com
According to a new study, there are at least 50 billion total wild birds—or six birds for every human on the planet.
The new paper, published this month in the journal Proceedings of the National Academy of Sciences, examined data collected by users of the citizen science database eBird and compared it with data collected by Partners in Flight and BirdLife International to check the accuracy. The researchers then combined the three pools of data to create an algorithm that estimated the population sizes for other species that were not the subject of the professional studies and lacked significant data, reports Adam Vaughan for New Scientist.
“The really big breakthrough in this paper was we could take the scientific data and the citizen science data and then fill the gap for birds which are not studied by professional scientists,” says ecologist and co-author Will Cornwell of the UNSW to Lisa Cox for the Guardian.
Out of all 9,700 species analyzed, four birds reached what the researchers call the “billion club,” or species with an estimated global population of over a billion. These included the house sparrow at 1.6 billion, the European starling at 1.3 billion, the ring-billed gull at 1.2 billion, and the barn swallow at 1.1 billion.