Right in the middle of the Dee Estuary (SJ185875) is the island of Hilbre - a tidal island only accessible on foot for a few hours at low tide. Every autumn, it attracts thousands of oystercatchers which come here to feed and rest.
Like other long-legged birds, oystercatchers often stand on one leg and pull the other into the warm feathers covering their bellies in order to conserve heat.
As well as oystercatchers, curlews also flock here in good numbers, generally to feed in the soft mud and sand of the estuary, but also, on occasion, among the rocks. The majority of the birds that come to Hilbre are migrating waders, but some smaller birds pass through too.
Chris Williams is an electrician by trade, but he spends every spare hour counting and ringing birds here on the island. There are also seals, and this lazy lot are making use of the sand banks at low tide. Behind them on the North Wales coast is the headland of Point of Ayr.
Colin Wells, is the RSPB warden responsible for coordinating the huge job of counting the estuary's 100,000 or so birds.
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ALSO ON BBC.CO.UK:
Former RSPB wildlife officer and now BBC Wales presenter Iolo Williams talks about Hilbre island... 
