A study conducted by the American Museum of Natural History suggests that there are about 18,000 bird species in the world. Previously, scientists believed the number of species was about half of this potential new total.
The work done by researchers focused on "hidden" avian diversity, meaning birds which that look similar to one another, but are actually different species. Most checklists used by bird watchers and scientists claim that there are 9,000 to 10,000 species of birds. This number was determined by the "biological species concept," which defines species in terms of which animals can breed together.
This new research suggests that the biological species concept is an out-of-date tool used in the study of birds. Rather, studying birds through morphology—the study of physical characteristics like plumage pattern and color—showed nearly two different species for every 200 birds studied!
The scientists who collaborated on the study believe a combination of the biological species concept and morphology could yield the most accurate results. The continued study of birds and the possible increase in the number of species has implications for preserving biodiversity and invigorating many other conservation efforts.