But I just want to point out a couple of things with this slide. Previous work on birds of paradise, almost all of which has been done in the Ornithology Department at the American Museum of Natural History over the last four or five decades, has recognized about 40 to 43 biological species. What I did is go through all of the collections that we have for birds of paradise and look at this whole problem again from the standpoint of phylogenetic species. So I would examine variation within these different populations and ask, are they diagnosably different? In some instances, they may be a little bit different and they may have been described as subspecies so the names are already there, but I asked are they diagnosably different or not? When you look at these populations in this way, you find out that there's about 90 phylogenetic species, about twice as many.
In my study some of the subspecies within these biological species were elevated to species rank about 65 of them actually were all elevated to species rank. But then there are a number of subspecies that really aren't diagnosably different from other subspecies. So, you synonymize those, you sink them. So you end up with about twice as many phylogenetic species of birds of paradise than you do biological species.
Several colleagues and I have done a study of the world's birds. We took random samples of the world's birds and asked within this random sample of biological species - a couple of hundred of them - how many phylogenetic species are there. As it turns out, about twice as many. So we estimate that approximately 18,000 phylogenetic species of birds exist in the world today, rather than the 8500-9000 biological species.
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