Despite its name, the Oystercatcher doesn't "catch" nor usually eat oysters, but it does eat other shellfish including cockles and mussels.
This is the Eurasian Oystercatcher, also known as the Common Pied Oystercatcher.
It is also known as the Sea Pie (from pied meaning black and white). These have muddied their vivid red/orange bills
probing for small shellfish and worms.
The range of the Common Pied or Eurasian Oystercatcher is coastal Western Europe, Central Asia and coastal Far East.
While UK birds are resident, Scandinavian, Central Asian and Far Eastern birds migrate south for winter.
Size comparison with Black-headed Gull
They can form huge flocks - see link below