Marsh-or Willow-tit

One of the wintervisitors is this lovely bird, having a small black cap.
He is either the Willow-tit, (Matkop), (Parus Montanus), or
the Marsh-tit, (Glanskop), (Parus Palustris).
Look-alikes, only their song is different.

It is raining all day, however he is coming all the time to the feeding table.