In North America there are seven native species of chickadee. Two of those species are the Black-capped Chickadee (Poecile atricapillus) which are found from New England to the West Coast along the northern tier of the United States and southern Canada, and the Carolina Chickadee (Poecile carolinensis) which resides in southeastern U.S.

The two species look extremely similar but under normal circumstances a birder can just look at the range map and go by that. If it is in the Black-capped range then it is that species and the same for the Carolina. But for a very thin strip across the U.S. there is a problem.

The native range of these two species overlap in a very narrow zone going from New Jersey to Kansas, and that zone takes a dip south along the Appalachian Mountains. In that narrow zone where the two species meet it becomes nearly impossible to tell one species from another since they can hybridize. And to add to the identity challenge in the overlap zone, each species can learn the song and call of the opposite species.

So here at my feeders, they are not Black-capped Chickadees or Carolina Chickadees, but just Chickadees. That keeps it simple.