There are 18,000+ species of birds in the world, not 9,000+ as commonly accepted. Possibly as many as 30,000.
That's the opinion of four ornithologists, including two who taught at the University of Minnesota. They made their case for this bold position in a research paper published in November in the on-line scientific journal Plos|One.
It’s not that birders somehow have overlooked half of the bird world. The birds have been seen. Birders just haven’t looked closely enough.
Confirmation of this lies at the molecular level, the four ornithologis say. That is uncommonly close.
The Minnesota men, co-authors of the paper, are Drs. Robert Zink and John Klicka.
Zink until last year held the Breckenridge Chair in Ornithology in the Bell Museum at the University of Minnesota. He left to take a position at the University of Nebraska.
Klicka is Curator of Birds and Professor at the University of Washington's Burke Museum. He did his undergraduate work here as a student of Zink.
The title of the paper is “How Many Kinds of Birds Are There, and Why Does It Matter?” Lead author was Dr. George F. Barrowclough, American Museum of Natural History. Co-authors were Zink, Klicka and Dr. Joel Cracraft, also of the museum.
In the birding world the word “split” means that one species has been determined to be two. It happens every year, ornithologists given this responsibility accepting new research, elevating a bird(s) to species level.
Clues can come from something as simple as range or song or mating compatibility. One species might be found on the west side of a state, its counterpart on the east.
“Many of these splits have been shown before,” Zink wrote in an email.
For example, he wrote, recent research showed that there were two species of the shorebird willet, not one. Winter Wren, a Minnesota nester, has been split by geographic range, becoming Pacific and Winter wrens (west and east).
Red Crossbills, currently a single species, give call notes as they fly in northern Minnesota. At least 10 distinct call types are recognized. Zink and his associates would say there are 10 species of Red Crossbill (a suspicion held by some birders for years).
“This goes on and on,” Zink wrote. “Many, many species have been found to be two or more.” Others await discovery.
“There are very few if any species in our analysis,” Zink wrote, “that are not (physically) or geographically discrete.” The study did not include all bird species. xxxxxxx
“What we have done is essentially forecast where the endpoint might be,” he wrote, “It’s somewhere in excess of 20,000 (bird) species (worldwide)”
He thinks it might be as high as 30,000.
This position is corroborated by study of molecular genetics, Zink said, all explained in the paper. These are details not visible with a better pair of binoculars.
Why does it matter? It’s of conservation importance. We have to understand what we seek to preserve.
It’s possible that birders eventually could find it difficult to know exactly what they’re looking at. That was an issue for some of us long before the study was published.