18 February 2021

Which bird species is the most numerous on earth? It depends on what you’re counting. All birds? Or just wild birds?

For all birds, the domestic chicken (Gallus gallus domesticus) wins the prize with 25.9 billion as of 2019.

Chickens live on every continent except Antarctica as shown on the map below. (Gray indicates absence. Yellow to brown shows increasing density.)

Compare the chicken map to human population density and you’ll see a correlation. There are 7.8 billion humans on earth as of March 2020.

As for wild birds, the sparrow-sized red-billed quelea (Quelea quelea) is the most numerous with a population of 1.5 billion as of 2018.

Queleas live only in Africa and thrive best where human grain crops provide abundant food. Queleas correlate to humans too, but not nearly as much as chickens.

Learn how chickens became the Most Numerous Bird On Earth in this 2014 vintage article (at the link).

(photos and maps from Wikimedia Commons and PLOS ONE; click on the captions to see the originals)