A few decades back, Princeton used to be smack in the middle of the zone of hybridization, making it virtually impossible to identify Chickadee species with certainty, short of a DNA test, since a hybrid individual can take on characteristics, including calls, of both species. With global warming, the very narrow zone has been moving northward at a rate of 0.7 miles per year, so that with each passing year Princeton is slipping out of the hybrid zone and into the Carolina zone. Tough to tell with this image, but your prior Chickadee post seemed to lack the "hockey stick" appearance caused by the white secondary edges of the Black-capped, suggesting this could be a Carolina. But the safest course, for now, would be to call it a "Chickadee sp." Once again, a very fine image.