||Pimm S, Raven P, Peterson A, Sekercioglu CH, Ehrlich PR. Human impacts on the rates of recent, present, and future bird extinctions. Proc Natl Acad Sci U S A. 2006 Jul 18 103(29):10941-6 DOI: 10.1073/pnas.0604181103 abstract and p.10942 left column 5th paragraphPubMed ID16829570
|| BirdLife International (2000) Threatened Birds of the World (Lynx Edicions and BirdLife International, Cambridge, U.K.)
||Abstract: "Unqualified, the statement that ≈1.3% of the ≈10,000 presently known bird species have become extinct since A.D. 1500 yields an estimate of ≈26 extinctions per million species per year (or 26 E/MSY)." P.10942 left column 5th paragraph: "Counting Historical Extinctions. Birdlife International produces the consensus list of extinct birds (primary source, ref 13) and a regularly updated web site www.birdlife.org/datazone/species/index.html. Hence-forth, [investigators] call these sources simply Birdlife. Until the May 2006 revision, the list of recent extinctions totaled 129 species, or 1.3% (primary source)."