The Oystercatcher is a wading bird which you’re most likely to see on our West Wales coast. Particularly found around the mouth of estuaries such as the Teifi, Tywi and Dyfi. Look out for the oystercatchers hunting on rocky and muddy shores of Pembrokeshire, Ceredigion and Carmarthenshire for shellfish to eat.
The birds form huge flocks in winter and smaller groups in summer, and you’ll often hear them before they come into view making their typical screaming ‘peep’. Although their plumage is strikingly black and white, they sometimes look all-over dark if viewed against the light. They are about the size of a pigeon. They do not breed in West Wales but nest on the ground at inland sites. Chicks are extremely cute and emerge from the egg running and are able to forage for their own food immediately.
Watch the birds come whizzing in towards a sandbank and you’ll see how they seem to fall in a jumble, running along the sand. They argue amongst themselves and chase off other waders, piping and clamouring to establish dominance. They are not averse to stealing food from each other as well as other species – quite aggressive in their behaviour! The Oystercatcher’s bill is long, straight and bright orange – strong and powerful for prising open the shells of molluscs – particularly cockles and mussels. It also eats other invertebrates which it digs out of the mud but doesn’t eat oysters!
A remarkable fact about these birds is that they display resource polymorphism: the bills of individual birds develop differently, allowing them to attack their prey in different ways. Three types of feeder have been observed within the common Oystercatcher population:
1)  Stabbers – these get hold of a big mussel and stab at the join of the two shells to prise them apart.
2)  Hammerers – their bill is thicker and more robust. They lay the mussel on its side and smash into it.
3)  Tweezers – a fine, delicate bill ideally adapted to poking into sand for worms. Usually females.
So if you’ve got a good pair of binoculars and a fortnight to spend on the West Wales coast, you could be a witness to a flock of Oystercatchers changing their feeding technique…