IUCN Red List status for (a) all birds, (b) globally threatened birds as of 2017

Using the criteria and categories of the IUCN Red List (IUCN 2001), BirdLife International’s 2017 assessment of the world's birds concluded that 1,469 species (13% of extant species, or one in eight) are globally threatened with extinction (see figure a). These comprise 222 species classed as Critically Endangered (meaning that they are considered to be facing an extremely high risk of extinction; see figure b), 461 species assessed as Endangered (very high risk of extinction) and 786 listed as Vulnerable (high risk of extinction). An additional 1,017 species are considered Near Threatened because they are assessed as close to qualifying as globally threatened. Hence a total of 2,486 species or just under a quarter of all the world’s birds are treated as global conservation priorities. Only 58 species (0.5% of the total) are considered insufficiently known to be able to assess their threat status, and so are classified as Data Deficient.

Threatened species are not evenly distributed among bird families. There are particularly high proportions of threatened species among cranes (73%), albatrosses (68%), parrots (28%), pheasants (20%) and pigeons (20%). Furthermore, families and genera with few species have disproportionately high numbers of threatened species (Purvis et al. 2000). Even allowing for these taxonomic effects, larger-bodied species and those with low reproductive rates (owing to small clutch sizes) are also more likely to be threatened (Bennett and Owens 1997).