Taxonomy... yes, the debates go on. There are several lists of birds out there, and no sign that things will be agreed upon and coordinated in the near future. Regarding woodpeckers, here in this photo is one taxon that moves between being a 'species' or a 'sub-species' depending upon which 'authority' is followed. I have this down as an American Three-toed Woodpecker Picoides dorsalis, although it was, and still is by some, regarded as a race of Picoides tridactylus. Photo taken in Oregon, USA, July 2014, Gerard Gorman.