Since I live in Northern Virginia, I'm on the range border for Carolina and Black-capped Chickadees - two species that are nearly impossible to identify in this area.
So, some of my Chickadee images may be either species, especially since I haven't got good enough hearing to use their calls as a discriminator.
Here's a short 'YouTube' video taken at our home in Warrenton, VA: "Pair of Carolina Chickadees"