Smooth v Crunchy

As an experiment, I tried smooth peanut butter to see if it was more popular than crunchy. The first day, I caught sight of a new visitor but he didn't linger. Yesterday, he was to and fro a few times, but never long enough for a photo. Today, he's made the smooth peanut butter tree his own. I can't ID him easily. Marsh tit or Black cap? I've never seen either in my garden before.