When is a Junco a Junco? Scientists continue to change the names of birds
Why is it that birds of the same species may look very different in various regions, but have the same name? For instance, Dark-eyed Juncos in the Pacific Northwest may have a reddish back and a dark “hood” (Oregon race), while Dark-eyed Juncos in the northeast are generally a slate-gray color, without a hood (slate-colored race). Who decides where the lines are drawn between species? Why can birds that look very similar, like Black-capped Chickadees and Carolina Chickadees, be distinct species, while others that look obviously different, like Dark-eyed Juncos from the Oregon and slate-colored races, be the same species?
Dark-eyed Juncos of the “Pink-sided” race, like the bird seen here, commonly winter in Colorado, Arizona, New Mexico, western Texas, and northern Mexico.
A history of name changes
Committees of 8-10 highly experienced ornithologists and taxonomists make official changes in species names. For North American birds, the Committee on Classification and Nomenclature of the American Ornithologists’ Union (AOU) maintains the official checklist. AOU checklists are updated every few years as new information on bird biology leads the committee members to either divide one species into two or more species (splitting), or to group species together under one name (lumping). Changes are often made based on new information regarding the genetics of the birds, how birds communicate (song-types), or the frequency of hybridization. Some groups of birds have been split and lumped several times. For instance, Dark-eyed Juncos had been split into as many as 7 different species before being lumped together under one name. Members of the titmouse family have been split from 3 species to 5 species since 1983 (see the history of name changes in titmice (see the history of junco and titmouse name changes below).
The Oregon race of the Dark-eyed Junco, easily distinguished by the dark “hood”, winters in much of the western U.S. and in British Columbia. Vagrants may be found across the continent.
Tufted Titmouse is split into two species
This year, the AOU committee has made a change of note for FeederWatchers in Texas, where there is now a “new” species that may appear at feeders.The American Ornithologists’ Union recently divided the Tufted Titmouse into two distinct species.
The Tufted Titmouse, familiar to many FeederWatchers across eastern North America, continues to be known by the same name. However, the race in south-central Texas has been “split” off from the Tufted Titmouse and named the Black-crested Titmouse. The two species look very similar, with the only obvious differences being in the crest. The crest of the Black-crested Titmouse is indeed black, and is often raised higher than the gray crest of the Tufted Titmouse. The change was made because scientists have recently discovered that the two species are genetically and vocally distinct. Despite the fact that they are now considered distinct species, they do hybridize where they come into contact with one another along a narrow zone through east-central Texas.
How to report titmice and juncos to FeederWatch
What about those confusing Juncos? While the Oregon, pink-sided, white-winged, slate-colored, and gray-headed races are all considered Dark-eyed Juncos, we’d like online FeederWatchers to report which race is seen at your feeders. With this information, we can map the geographic distribution of the various junco races in the winter. While the various races of juncos do not automatically appear on the checklist of likely species found in your region, you may easily add the various races to your list by clicking on the “Add a Species” button. Learn more about the junco subspecies on the Lab’s All About Birds web page .
FeederWatchers in the southwest should note that Yellow-eyed Juncos may visit feeders in southern Texas, Arizona, and New Mexico. Please submit any sightings of these species on a Rare Bird Form, and use the write-in section on your standard data forms to report Yellow-eyed Juncos.