Leaving out poultry and pets, roughly how many wild birds are alive in the world?
Try it yourself first
🐘 Animals · birds
Enter an estimate in birds.
Notepad
End a line with = to calculate it.
Show the answer and the method
Answer
About 50 billion birds
Only four wild species number more than a billion individuals: the house sparrow, the European starling, the ring-billed gull and the barn swallow.
How to estimate it
Earth's land area is 150 million square kilometres, which is 15 billion hectares. A rich woodland can hold 10 or more birds per hectare, farmland a few, and deserts or ice sheets almost none. Take 3 birds per hectare as a worldwide average. 15 billion × 3 = 45 billion birds. A 2021 study based on citizen science data arrived at about 50 billion wild birds.
Source: Callaghan, Nakagawa and Cornwell 2021, PNAS
More questions: Animals
- Roughly how many species of birds are known to science today?
- A peregrine falcon folds its wings and dives onto its prey. What is the highest speed recorded in such a dive, in kilometres per hour?
- Roughly how many chickens are alive on Earth at any given moment?
- Researchers from Hong Kong and Germany pooled hundreds of field studies to estimate the number of ants alive on Earth. What figure did they arrive at?
- The Arctic tern commutes between the Arctic and Antarctica, chasing summer all year. About how many kilometres does one bird fly in a single year?