A tern on the up

IN the conjugal clamour of nesting terns around the eastern shores of Ireland, the grating aaak! of the roseate tern, fresh from Africa, may seem to show new vigour. The bird has, indeed, much to celebrate: an upturn in its harassed and fragile population, and European money for its conservation on both sides of the Irish Sea. For a species reduced in north-west Europe to a mere 561 pairs just a decade ago, the auguries begin to be hopeful.

The saga of the roseate tern's misfortunes begins with images like this one from Skerries, Co Dublin in the mid 19th century: "An intelligent boatman when sailing to various islets to observe these birds described, on one occasion, seeing the water almost white with their plumage, strewed round the boat which two persons, representing themselves as doctors from the city, had hired for the occasion, so many being destroyed that the boatman begged them not to kill all, but to leave a few birds to breed."

Such was the slaughter for the millinery trade and the plundering of eggs for collectors that roseate terns vanished from Ireland by 1900 and, indeed, came close to extinction altogether. The Skerries incident can be set against another description, of terns - roseates and others - being killed today on their wintering grounds by the schoolchildren of Ghana: "Fish, with hooks inside them, are inflated by blowing into the swim bladder, attached to fishing lines and used to catch birds from jet-ties and piers. Terns feeding in-shore are knocked from the air with Storms."

When the birds re-established in Ireland, in 1930, a dozen pairs nested on Rockabill (off Skerries) and slowly if erratically built up their numbers. In the 1970s, they survived the wholesale predation of their eggs by herring gulls and spraying of vegetation which destroyed their nesting cover.

By that time, the largest nesting colony of roseate terns in Ireland - and, indeed, in Europe - had grown up at Tern Island, an unstable sandbank in the entrance to Wexford Harbour. In the early 1970s it had reached almost 700 pairs. Then came high tides which washed the nests and eggs away and winter storms that finally demolished the island.

Some 220 pairs of dispossessed roseates transferred in 1978 to islets in Lady's Island Lake, a lagoon on the south Wexford coast. Here, despite the company of hundreds of pairs of sandwich, common and Arctic terns, they were attacked by rats, which ate most of the eggs and a lot of the chicks, and then also by gulls, mink and foxes. What an incredible series of misfortunes!

From that low point in the 1980s, conservation control by the Wildlife Service and summer wardening by the IWC (now BirdWatch Ireland) has helped to nurse the colony back. Wardening of Rockabill has done even better so that Ireland reached a total of 677 pairs of roseates last summer - almost four-fifths of all those breeding in north-west Europe. Now, through BirdWatch Ireland, the EU is paying for new research into the feeding ecology of the roseates of Ireland and north Wales.

The colony of mixed terns on Irish, in Lady's Island Lake, has become the largest in the State, and its summer clamour dramatises the value of "Ireland's Great Barrier Coast", as Jim Hurley naturalist, biology teacher and campaigner, likes to describe the South Wexford littoral.

The barriers are the great ridges of sand and gravel, rolled in by the sea, which wall off the brackish lagoons of Lady's Island and neighbouring Tacumshin. This is a strange coast, shifting and eroding ever since the Ice Age, and its "high energy" dynamics are explored in Jim Hurley's new 200-page compendium, somewhat perversely entitled "Water Level at Lady's Island Lake, 1984-1996".

It certainly has pages of tables and figures, but also much else. Chapters on local natural history include, for example, the fortunes of cottonweed, Otanthus maritimus, at its last surviving stand in Ireland. This woolly perennial herb, already extinct in Britain, grows in the gravel barrier at Lady's Island Lake, one of many rare plants that have been vanishing from our shores. There used to be a mile of it, but the exigencies, of "The Cut" have been steadily whittling it away.

"Cutting the lake" - breaching the barrier in springtime to let the lagoon run out into the sea - has been going on at intervals since 1682 and almost annually in recent decades, uncovering acres of Nile-rich mud in which to grow early potatoes. When, where and how to cut has been a source of local debate for much of that time. In 1954, the county council brought in machines to do it, so that the Marian Year Pilgrimage could walk the path round Lady's Island (the major island in the lagoon) with dry feet.

The operation of opening the breach with a digger appears to confront Chaos Theory in a fairly direct manner. There is no such thing as a "good" or "bad" cut. Jim Hurley insists: once the lake water begins to flow, what happens is quite uncontrollable and sometimes catastrophic.

His description of "a barrier burst", such as the one in 1988, is vivid, indeed. "When the leaping water reaches a critical threshold, id&ally aided by a falling tide and a freshening wind backing northerly, the rushing water boils furiously, the distinction between gravel and water breaks down, both merge into one cascading, fluid mass, the sidewalls of the trench collapse in two to three metre-wide slips at a time, causing the trench to widen dramatically as the whole contents of the lake disgorge into the sea."

Whether this sort of thing is realty good for a four-star international wildlife habitat, including a prime tern island vulnerable to rats and foxes, has been adding to the burden of decision on when, where or if to "cut" as water levels rise.

Since 1990, this has rested with a local voluntary committee, meeting in the pub to achieve (remarkable) consensus between BirdWatch Ireland, the Wildlife Service, local game protection and shooting interests, landowners and farmers, Our Lady's Island Pilgrimage Committee - and Jim Hurley.

This year they didn't have to meet, because of the drought. They are more than ever hoping that, with Lady's Island Lake and Tacumshin under Special Area of Conservation orders, Michael D. will get his money from the EU Life-Nature programme to pay for "permanent engineering solutions" - a long trench, enough drainage pipe and a pump-house. Where would our wildlife be without Europe?