Drifting balloons can mean death for turtles

Another Life: On the shore below Croagh Patrick, what's left of a long spit of dunes curves out towards the drowned drumlin islands of Clew Bay. Bertra Strand was once quite a lonely spot, out beyond farmland: you felt the power of the Atlantic, drumming away to the horizon.

Now the headland is tamed with bungalows, and caravans pile up at the seaward end of the road. The ocean, however, stays wild. It was near here that a walrus, of all things, spent a recent Easter, mooching along the rocks. And the last time I was summoned to Bertra it was to inspect the washed-in corpse of a pygmy sperm whale, looking much less exotic than its name. Another cadaver, in much better shape, brought us there last week, trudging out along the sand with an escort of small boys.

One dead leatherback turtle may seem very like another - this was our third in Clew Bay over the years - but there is always something compelling about this primeval, lugubrious reptile: you can see why some ancient mythologies made it carry the world on its back. This one was young, about five feet long: not a scar on its smooth black hide or the powerful, leathery flippers. The point of its bill was as sharp as an eagle's and the mark on its forehead, as unique to each turtle as a fingerprint, was fresh and rose-pink.

The boys picked up rocks and bounced them at full force off its back and head. We yelled, demanding respect for an animal so freshly out of breath. They looked blank: "It's dead, isn't it?" I reached for blockbuster numbers - the 100 million years of its history on Earth, the thousands of miles of its Atlantic journeys, the century of its lifespan if people leave it alone. The boys were bemused.

Leatherbacks are now in great trouble as a bycatch of human fisheries. In the Pacific they are threatened with extinction within a decade, tangled in longlines trailed for more than 100 kilometres. In the North Atlantic, too, they run a daily gauntlet of an estimated 1.4 million hooks.

Leatherbacks can dive to remarkable depths - 1,230 metres has been measured - but more usually to less than 250 metres, just enough to enmesh them in the longlines' deadly web. Fishing nets and inshore lobster-pot ropes add to the drownings.

Maps of the travels of radio-tagged leatherbacks show them roaming out from Caribbean nesting grounds and traversing the Atlantic quite independently of currents. Marine scientists in UCC and the University of Wales are poised again this summer to fix transmitters to any turtles rescued from entanglements by fishermen - part of a collaborative study of leatherback migration to the Irish Sea. It also deals with jellyfish, the turtles' staple food: in particular, the giant Rhizostoma, the "root-mouth" or "barrel" jellyfish with a thick dome of a bell that may be half a metre across. A low-flying plane has been used to count huge numbers of Rhizostoma that crowd into bays in Wales.

Not everything a leatherback turtle swallows turns out to be digestible or nourishing. In particular, a drifting, half-inflated balloon, mistaken for a jellyfish, can end by blocking the valve where the stomach empties into the gut. Since a Canadian marine conference first brought this and related wildlife risks to notice in 1989, the mass release of balloons at public and corporate events has been increasingly controversial. San Francisco is one of many US coastal authorities to have banned the practice, and Britain's Marine Conservation Society supports similar measures. Last month, Friends of the Irish Environment has also asked President McAleese to boycott such events.

The balloon industry points out, however, that those used in most mass releases are made of biodegradable latex that breaks down "faster than an oak leaf". It has commissioned research to show that balloon fragments take their time in working through turtle intestines, but end by doing no harm.

Perhaps 95 per cent of gas-filled balloons rise to an altitude of more than three kilometres and burst into fragments. Critics are more worried about the five per cent that don't burst, but wobble on for miles to end up in the sea. Even oak leaves, they point out, take six months to degrade, and immersion slows the decay of latex. Whales and dolphins are also considered at risk from swallowing balloons in mistake for squid, but, as with the world's turtles, they face many more obvious and immediate threats from human activities.

Tomorrow's Whale Watch Day, organised by the Irish Whale and Dolphin Group, is a celebration of cetacea. For details of gatherings at 10 Irish headlands, visit www.iwdg.ie.

EyeonNature 

Is it possible that I could have seen a green woodpecker earlier this month in Clonbur, Co Galway, at a busy bird table at the back of a pub. It had a most vivid red skull cap and its feathers were yellow.

Anne Marie Pollard,
Dún Laoghaire. Co Dublin

More likely a goldfinch. Green woodpeckers are not found in Ireland.

On a holiday on Inishbofin we went on a birdwatching course with Gordon D'arcy. We saw shags, a great northern diver, ringed plovers, a curlew, choughs, a red-breasted merganser, a grey heron, common gulls, greater black-backed gulls, oystercatchers, common terns, a sand martin colony, fulmars and their eggs, Manx shearwater nests at the top of the cliff and a black guillemot on the sea. We saw lots of other birds and heard lots of corncrakes. The most exciting event happened on an island close by. We were trekking across it with our families when we were attacked by two big birds. They flew at us and dived and swooped. They were great skuas nesting on the island.

Kevin Lyons (10) and Sean Griffin (11), Dublin