Swirling, diving and swooping sights

A TIGHT formation of dunlin rockets down the channel towards me, turns and disappears into thin air. Five seconds later and fifty metres away, they reappear as a sudden blink of light before turning and disappearing again.

Now you see them, now you don’t: nature is a master illusionist. The winter plumage of this migrant bird, barely bigger than a sparrow, is brownish-grey on the back and head. Flying low, at high-speed, in a compact mass, they are ‘lost’ against the background of mud and water. When they turn, their white bellies catch the light and they are then, momentarily, a mass of blinding spangles before they turn and ‘disappear’ once more. The manoeuvres of flocks of birds are one of the most exciting sights in nature and winter is the time when one may best view them.

Of the shore birds, dunlin are especially spectacular; they rise like wisps of smoke blown on the wind. Perhaps a hundred pairs of dunlin breed in Ireland while some 150,000 arrive from Russia and Scandinavia in winter. Their camouflage disrupts the normal effects of light and shade. When light falls on an object, its shape is emphasised by brightening the upper surface and darkening the lower: light above, shadow below. The plumage of many birds reverses this effect: the upper parts — the head and back — are dark and the belly is pale. Thus it is with dunlin, as with other birds of bare, open terrain like estuaries and seashores.

When threatened, the flock takes to the sky in a compact mass, making it difficult for predators to pick out an isolated victim — sparrowhawks or peregrines will rarely fly into the midst of a bunched flock. Meanwhile, the flock performs extraordinary manoeuvres in tight formation, making the predator’s task of catching one bird harder still. The sudden unanimous high speed swervings of a flock of dunlin, knot or starlings, or the ‘falling leaf’ descent of a flock of golden plover, bewilders the predator and is the small birds’ best defence.

One bright January morning last week I promised myself I’d put in a three or four-mile hike before lunch but when I reached the bay a flock of dunlin took to the air and I couldn’t but stop and marvel.

I had seen them a hundred times before, the mass of small waders rocketing in tight formation over the muddy channels of the bay, rising and falling like notes in a symphony, slow as they ascend, fast as they fall, swooping and sweeping in undulations, suddenly rising from horizontal to vertical, a pillar of birds expanding and contracting like a concertina or one of those Christmas decorations we take out each year. In pennants and banderas they flew, like skirls of notes on the wind. Their flight was like a musical score written in the sky and I stood enthralled.

There were just a few hundred to start with, but their numbers swelled as they swept down the edge of the channel, plucking companions off the mud banks. The rush of their wings reached me as they flew past, fifty metres away from where I stood alongside the bay at Cilmanistir Wood. Backward and forward they hurtled towards the abbey at the end of the bay, now rocketing past me again as if heading for the sea but turning again, spiralling high, then diving earthwards, a sight to take your breath away that January day.

On migration, these tiny birds, weighing less than two ounces, fly as high as 23,000ft where the temperature is 20 degrees below zero. During the Cold War, a migrant flock coming from Russia was picked up on the radar and mistaken for aircraft, causing fighter jets to be scrambled from British bases in the North. Happily, they did not open fire.

Later when we went west to Muntervary, on the Sheep’s Head peninsula, the horizons were claustrophobic, grainy with rain, the mist and sea uniting out beyond the dark rocks.

No wonder we are famous for our fairytales. As the sky darkened, the bare bushes, bent by the wind, seemed like shawled hags, a regiment of them, retreating. Poor Marys of the Mountain swirled away below us weaving down the wet, green hill.