Who Is Most Numerous?

Girl holding 2-month-old chicken (photo from Wikimedia Commons)

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.

Hen and chicks (photo from Wikimedia Commons)

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

Worldwide distribution of domestic chickens, gray=absent (gray added to map from “Mapping the Global Distribution of Livestock”, PLOS ONE, 2014)

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.

Human population density, 2005 (map from Wikimedia Commons)

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.

Distribution map of red-billed quelea (map from Wikimedia Commons)

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)

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