Winter Visitors Arriving

It's a little calmer and warmer today, grey but not actually raining. Down at the creek this morning (half tide again) there was a larger than usual variety of visitors, but almost all alone; one swan, one kingfisher, one jay, one robin, one crow, one sandpiper. The sandpiper is a regular winter visitor, seen for the first time today. This is the third winter I have seen it at the creek, but there only ever seems to be one. There were quite a lot of ducks, as well. A mallard with what seemed to be three half grown ducklings, and two gadwall. A grey mullet was floating idly with his back out of the water, then suddenly leapt a good foot clear of the surface, somersaulting before diving back in. I wonder what upset him?