Friday, September 24, 2010
David Sibley writes about the difficulties involved in identifying these two new species. Telling them apart is very difficult, and best done by their call notes. Even differentiating the call notes is challenging. So why are these species recognized? The DNA patterns of these two populations do not mingle and are consistent, even where the two forms overlap, for call and song types. (For a detailed discussion of these wrens' genetics, follow this link.) I guess fortunately for us Minnesotans, the Pacific Wren is very unlikely to occur here--see the maps posted by Sibley. Birders along the front range of the Rockies, where both species migrate or winter, will probably not be sure which species they encounter.
Posted by Dan Tallman at 8:52 AM