Earth is home to 50 billion birds, new study finds

Earth is home to 50 billion birds, new study finds

By Lucy Jones  May 19th, 2021

There are six birds for every human on the planet according to new research out of UNSW.


Citizen science and advanced algorithms have been used to determine the global bird population for the first time. The research, conducted by a team of scientists from the University of New South Wales, estimates that there are 50 billion individual birds on the planet. That's six birds for every human.

"Humans have spent a great deal of effort counting the members of our own species — all 7.8 billion of us," Associate Professor Will Cornwell, ecologist and co-senior author of the study, said in a statement.

"This is the first comprehensive effort to count a suite of other species."

The study found that, of the 9,700 different bird species on earth, a handful of species make up the majority of the world's bird population with rarer birds only found in much smaller numbers. The research helps scientists understand which bird populations are currently at risk and where to focus conservation efforts.

"Quantifying the abundance of a species is a crucial first step in conservation. By properly counting what’s out there, we learn what species might be vulnerable and can track how these patterns change over time – in other words, we can better understand our baselines," Dr Corey Callaghan, the study's lead author, explained.

The researchers found just four bird species belong to what they have called 'the billion club', these are: the House Sparrow (with a population of 1.6 billion), the European Starling (1.3 billion), the Ring-billed Gull (1.2 billion) and the Barn Swallow (1.1 billion).

In Australia, there is an abundance of some of our most iconic birds — Rainbow Lorikeets (19 million), Sulphur-crested Cockatoos (10 million) and Laughing Kookaburras (3.4 million) — but rare native species like the Black-breasted Buttonquail have populations of less than 100.

“We'll be able to tell how these species are faring by repeating the study in five or 10 years,” Professor Cornwell said.

“If their population numbers are going down, it could be a real alarm bell for the health of our ecosystem.”

Bird watchers all around the globe contributed to the findings, with data generated from more than 600,000 citizen scientists who logged bird sightings through online database eBird between 2010 and 2019.

“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,” Dr Cornwell told the Guardian.

The research captures 92 per cent of the world's bird species, with the remaining 8 per cent excluded due to lack of available data. The research team acknowledged this gap in the findings, with Dr Callaghan saying the numbers provide a starting point for understanding bird biodiversity.

"We will need to repeat and refine this effort to really keep tabs on biodiversity – especially as human-caused changes to the world continue and intensify."

You can read the study in full here.

Positive Environment News has been compiled using publicly available information. Planet Ark does not take responsibility for the accuracy of the original information and encourages readers to check the references before using this information for their own purposes. 


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Lucy Jones

Lucy started her career working as a writer and editor in print and digital publishing. She went on to create content for Australia's leading sustainable fashion platform while completing her Master of Cultural Studies. Lucy spends her downtime at the beach, crocheting and hanging out with her cat Larry. She believes words can change the world and is stoked to help Planet Ark spread the message of positive environmental change.

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