The Red List published by the International Union for the Conservation of Nature (IUCN) is the go-to database of the world’s imperiled species. Using standardized criteria, it categorizes each species along a spectrum of extinction risk ranging from Least Concern and Near-threatened to Endangered and Critically Endangered.

Range size is one of the criteria used to assign categories, yet, as birders know, a species may not be present throughout the area delineated in its range map. Looking to improve the categorization process, a team led by conservation biologist Natalia Ocampo-Peñuela, of Duke University, recently used elevation data and high-resolution satellite imagery to identify potentially suitable habitat for hundreds of forest-dwelling birds across the tropics. (The Gray-winged Cotinga above, a Brazilian endemic species, was one of them.) The Red List labeled 18 percent of the birds as threatened.

Not surprisingly, the refined ranges were smaller than the ranges used by the IUCN. The authors determined that if the IUCN range-size criteria were applied to the more accurate ranges, 210 of the species examined (43 percent) would be placed in a higher threat category. The total includes 189 birds that are now considered not at risk and, based on the new estimates of suitable habitat, could be considered Vulnerable, Endangered, or Critically Endangered. — Julie Craves

A version of this article appeared in the January-February 2017 issue of BirdWatching magazine.

IUCN Red List of Threatened Species.

 

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Originally Published December 30, 2016