How many bird species in the world?

Photo by BarrytheBirder

Are there 9,000 or 20,000 species in the world?

It's been almost a year since a study doubled the number of bird species in the world by redefining 'species'.   Joel Cracraft, an evolutionary biologist and ornithologist at the American Museum of Natural History in New York, and some colleagues, settled on a new figure at 18,043.   But it could be as high 20,000.   The new figure is an extrapolation of a study of 437 biological bird species, which on average, were split into 2.4 taxa each.   A current list of 9,159 species therefore grew to over 18,000.   How accurate and valid is this extrapolation?   No one really knows.   What I know is that I was right, a long time ago, to forget about being a lister. Now I just enjoy myself watching and listening and appreciating the simple existence of my feathered friends.   Which means I can experience the presence of a single species a hundred times and never stop marvelling at its differences and similarities to me.   Amen.

Please comment if you wish.

BarrytheBirder