Have you seen?

By TPN, in Arts & Lifestyle · 28-05-2021 01:00:00 · 0 Comments

Turnstone Arenaria interpres

Outside the breeding season, this cosmopolitan, chunky shorebird exploits inter-tidal areas from rocky coasts to river deltas and from mainland shores to remote oceanic islands. In the Algarve they can even be seen feeding along stone-lined rivers, like those in Lagos and Tavira.

The drab, variegated brown and black upperparts of the winter plumage provide protection from sharp-eyed hunting predators such as Merlin and Sparrowhawk in the seaweed-rich tidewrack of the northern oceans. No such threats exist on coral atolls!

In spring, birds adopt the brighter plumage pictured as they move north to sub-Arctic and Arctic breeding sites, where it provides effective camouflage in moorland and tundra vegetation. Perversely, though, some choose to nest on relatively bare ground. As a boy I was thrilled to find one by a small tarn in Wensleydale in June but the species has never been proved to nest as far south as Britain.

Turnstones wintering in Iberia are mainly from a north-western population breeding in Greenland and north-eastern Canada, although Scandinavian birds must pass through, as some remain as close as Morocco. They form loose, normally small, flocks at this season and are quite vocal, particularly when disturbed. The characteristic low, rolling chuckle is quite unlike that of any other wader call in our area.

As the name implies, Turnstones do overturn stones to seek the insects, crustaceans and molluscs that comprise the main part of their diet. Limpets and barnacles are opened by adroit use of the bill. Several individuals can cooperate to turn over a large object. They are not averse to feeding on carrion, such as dead fish and mammals, and human food waste. On the breeding grounds, insects and plant material, like crowberries, form a large part of their intake.

Birds defend their eggs and young vigorously, attacking skuas, gulls and Arctic foxes both singly and in concerted groups. Distraction flights and injury-feigning are also used to lure intruders (including humans) away from their nests.

Alan Vittery




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