I expected to hear the longed-for bubbling song of curlews, returning to their moorland breeding sites in the dale. Instead, staccato piping calls, carried across the water by the blustery wind, came from two dozen oystercatchers (Haematopus ostralegus), newly arrived from the coast.
A week earlier I had watched another flock on the edge of the North Sea, on sparkling, wave-washed sands and seaweed-draped rocks near Sunderland, but it is more than likely that today’s birds came from the west coast. Oystercatchers began nesting on banks of North Pennine rivers in the 19th century, gradually advancing up Cumbrian rivers from the Solway Firth and then colonising the Tees, Wear and Tyne in Durham and Northumberland; these birds may have flown over the Pennines, too.
Every year, at about this time, some oystercatchers come here to breed, arriving in their suave black and white finery, reminiscent of smart tuxedos but rendered comical by a long, stout, orange beak, and switch from a salty seaside diet of cockles and mussels to earthworms.
Once water levels fall, many nest on the gravelly banks of the upper reaches of the River Wear, though others choose tussocky grassland, a field or two below the heather moorland. Their pristine breeding plumage and beaks soon become spattered with mud when they probe for worms in cattle pastures.
They are the noisiest spring arrivals from the coast and their piping “klee-eep, klee-eep” territorial and courtship calls become part of the spring soundscape. Once they nest, this cacophony can reach hysterical intensity when intruders threaten.
Oystercatchers are fearless in their defence of eggs and nestlings. I have watched them see off ravens and stand their ground under hooves of cattle that graze too closely, and have often been subjected to their aural assaults when I’ve inadvertently ventured near a nest.
This morning I walked around the reservoir, keeping my head below the dam wall until I was opposite the flock, then eavesdropped; their excited “pic-pic” alarm calls to one another sounded almost conversational. As soon as I peered over the parapet, they took flight, wary as ever, an undulating ribbon of black and white winnowing wings, skimming the water surface.
It’s good to have them back.
