The two chickadee types look identical, so which is which? Apparently they don't know either, since they will breed with each other where the two overlap. Of course, I live in an area where they overlap, so I cannot tell which is which.
They are tough to photograph because they are always on the move. I have no idea how many pictures of empty branches I took on their behalf.
Really enjoyed your galleries! This one is a particular favorite, as I can well imagine how hard it was to capture them. Always on the move! Keep up the great work.