One of North America’s most beloved and familiar birds, the Yellow-rumped Warbler, may be at least three separate species, If the species were to be split, it would upend a status quo that has lasted for almost five decades and would restore two cherished common names that many bird watchers still fondly use.
For most of the last century the Yellow-rumped Warbler was two species, the Myrtle Warbler of the East (and far north) and the Audubon’s Warbler of the West. But in 1973 scientists lumped them based on evidence that the two species routinely hybridize in a narrow zone in western Canada.
Now, evidence from more than 37,000 regions of the birds’ DNA suggests that Myrtle and Audubon’s really are separate species—and so is a third, isolated form known as “Goldman’s warbler” that is almost entirely restricted to Guatemala. A fourth form known as the “Black-fronted” warbler lives in the mountains of northern Mexico but its species status is more debatable. Adapted from Cornell Laboratory of Ornithology