18,000 Bird species in the world? (1 Viewer)

Just thought I'd flag this up, as it's quite interesting, though my own interpretation is that authors are really stretching the definition of what a species is. Basically, according to a new study published here, there are almost twice as many bird species as we first thought.

In short, the authors did two things: (1) they randomly selected a sample of 200 currently recognised species, examined a wide range of specimens in museums and looked for diagnosable differences in plumage pattern, colour and morphology to see which could be split. (2) They looked at the genetics of 437 currently recognised species and distinct genetic groupings in each. For these analyses they concluded that there are around 1.9 to 2.4 "distinct" species per biological species and extrapolated from this to derive the total figure.

I'm no genetists / evolutionary biologist, but to me the whole underlying premise of the study is a bit strange. I.e. the authors derive their total by assuming any distinguishable sub-species is actually a good species. I don't really know enough about species concepts to comment on this seriously, but a mate of mine published a study a while back suggesting that things that are considered good species in birds tend to be quite a lot less genetically distinct that good mammal species, suggesting that ornithologists are a bunch of splitters compared to mammalogists!

Anyway, perhaps the UK400Club (UK800 Club??) will adopt this revised taxonomy...;-)

The concept of a "species" as opposed to a "subspecies", "form", "variety" or just a random difference not worthy of recognition is conflicting depending on who you ask, and over what taxonomic group. For instance in plants and fungi there are several "species" which differ only in tiny details (sometimes only geographic location, or the shape of certain spores), while there are birds that differ quite readily but are still considered the same "species" (for instance, many eastern/western subspecies from Europe-Asia and even across America).

I don't think we can ever find an absolute solution. As time goes on new authors go back, merge old species, while others later then split them again. There is rarely an ultimate consensus on the matter.