Today I saw a Herring Gull and a Common Gull (UK common names) "worm-dancing" on an area of wet grass. Worm-dancing is when the bird taps its feet on the ground rapidly in order to drum worms to the surface (that its a worm hunting behaviour might be conjecture, I'm not sure it's been proven).
Shortly after, a pair of Jackdaws landed and also began hunting, but without dancing. They walked over the area poking about in the grass, whereas the gulls stayed in the same place.
So my question is firstly, which species/families has worm-dancing been observed in, and secondly is this thought to be learned behaviour (this might be determined by it being a local phenomenon in certain populations)?
EDIT: Originally misidentified a common gull as a black headed gull (corrected above). Today I saw a black headed gull alongside the two larger gulls, and it was hunting like the jackdaws, not worm-dancing. There might possibly be a size/weight requirement to be able to worm-dance effectively, if we accept the hypothesis that it's a method of bringing worms to the surface.