Global abundance of birds

A study estimates the global abundance of bird species. Abundance estimates of fauna are important for research and conservation efforts. However, the abundance of bird species remains uncertain. Corey Callaghan and colleagues examined global occurrences and population estimates for approximately 92% of all extant bird species, using data from 2010 to 2019. Overall, the authors report, there are approximately 50 billion individual birds in the world, and the majority live in Palearctic and Nearctic biogeographic realms. Most bird species are rare, and 12% of species have population estimates of less than 5,000 individuals. Conversely, few bird species are abundant, and only the house sparrow, European starling, ring-billed gull, and barn swallow have an estimated global population of more than 1 billion individuals each. The authors also found that birds do not inherit abundance through speciation events, which is consequential for species' extinction risk. The most abundant orders of birds are perching birds, shorebirds, and waterfowl, whereas the least abundant orders are kiwis and mesites. Across feeding guilds, invertivores and omnivores are the most abundant groups of birds, whereas scavengers and nectarivores are the least abundant groups. The findings suggest that increased conservation efforts are necessary to maintain bird diversity, given that most bird species have few individuals, according to the authors.

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Article #20-23170: "Global abundance estimates for 9,700 bird species," by Corey T. Callaghan, Shinichi Nakagawa, and William K. Cornwell.

MEDIA CONTACT: Corey T. Callaghan, University of New South Wales, Sydney, AUSTRALIA; tel: +49-1573-727-8665; email: c.callaghan@unsw.edu.au

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