A “New” Species for Your Life List
Do you have a Winter Wren on your life list? The word on the street is that Winter Wren will be split into two species – “western” Winter Wren and “eastern” Winter Wren. The two Winter Wren groups breed side by side without any hybridization in a narrow zone of contact in northeastern British Colombia.
The Check-list of North American birds is the official source on the taxonomy of birds found in North and Middle America, including adjacent islands. This list is produced by the North American Classification Committee (NACC), an official committee of the American Ornithologists’ Union. Results of the voting are not made public until July in the annual Supplement to the A.O.U. Check-List.
Fortunately, Audubon Guides follows this list exactly and updates almost immediately each time there is a supplement published. Although the last updates included minor name changes for things like Nelson’s Sharp-tailed Sparrow becoming just Nelson’s Sparrow, sometimes there are major changes like Winter Wren.
Why was Winter Wren proposed as two species? It takes science to tease apart closely related species, sometimes called cryptic species. Scientists first noted that call notes were quite different between western and eastern populations. More recently, DNA from birds in each population showed a large divergence.
The scientists who conducted the research also wrote the proposal to the committee for splitting Winter Wren. They proposed naming the western population, Pacific Wren, while the eastern birds would remain Winter Wren.
What’s the difference? Eastern birds average more white spots on their backs and they have lighter-colored throats, and are duller brown or less rufous. But it is the differences in call notes that most notable (pun intended!). Calls of birds in the pacificus group are “noisier” and higher pitched.
When (or if) it becomes official in July, many of you will have a new species on your life list. But, more importantly, we all understand the ecology of these birds just a little bit better.