I was lucky enough to be alone in a hide, and see this. Anyone know whether it was Knot or Dunlin? There were also about 1,000 oystercatchers on the island next to the knot/dunlin.
Presumably waiting for high tide to abate, when they could return to feeding on the mud. A wonderful sight - and worth the long trek from the car park, through the mud (and with the wind blowing mightly chill!).
Wader murmuration - 10 seconds