Country diary: The plovers peck and the sandpipers probe

<span>A ringed plover feeding in Northern Ireland.</span><span>Photograph: Gerard O’Connor/Alamy</span>
A ringed plover feeding in Northern Ireland.Photograph: Gerard O’Connor/Alamy

I adjust my spotting scope and get a sudden close-up of these contrasting strategies. A ringed plover has paused nearby. It tilts its head, then rushes forward to stab its short bill into the sand. Further down the shore, a dunlin – a small sandpiper species – ambles around a low sawtooth of rock. All the while, it drills steadily at the sand with its longer, slightly downturned bill.

I look back to the sea. The tide’s leading edge chases a froth of sanderlings across the lower shore. A turnstone is impatiently flipping through clumps of seaweed. The glistening shallows are stencilled with silhouettes. I focus on a group of oystercatchers as they stroll through the water like day-trippers – until the level drops. Then they hammer their bright orange bills at the wet substrate. Behind them, an incoming wave has collapsed around a curlew’s thighs. This elegant shorebird is unruffled. It continues to probe its finely down-curved bill through the deeper water.

The tiered horizontals of the waves underline that, collectively, waders are variations on a theme. Their common ancestor evolved during the Cretaceous, and its body plan has been modified and finessed into this array of forms. From the lankiest curlew to the smallest sanderling, different lengths of leg and bill separate the species, like Russian dolls, along a gradient. The size and shape of a bill makes a specialist tool for a particular niche. Across today’s planet, however, waders are in decline. The thought yanks me from the scope. I blink into the sunlight. The ancestors of these birds survived the mass extinction that ended non-avian dinosaurs. Will their descendants survive the one caused by us?

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