There are at least 50 billion individual wild birds in the world, according to a new study. House sparrows alone make up about 1.6 billion of these.
Three other species – European starlings, barn swallows and ring-billed gulls also have a population exceeding one billion birds.
However, one in ten bird species are rare with fewer than 5,000 individuals, the study has said.
This “snapshot” of the global bird population will help in conservation efforts to save birds from extinction, says a team at the University of New South Wales in Sydney, Australia.
Counting the number of birds in the world is a complex task, with no definitive answers.
Past rough estimates have come up with 200 to 400 billion individual birds drawn from 10,000 to 13,000 bird species.
The Australian researchers analysed 9,700 species of living birds using data recorded by birdwatchers on the online database, ebird, over the past decade.
They refined the data using modelling and information from experts on the ground to come up with what they say is a more accurate estimate.
The study, published in the Proceedings of the National Academy of Sciences, suggests most birds are found in the northern hemisphere: in Europe, northern Asia, northern Africa, parts of the Arabian Peninsula, and North America.
In contrast, very few birds are found in Madagascar and the Antarctic.