Dark villain or easy scapegoat?

When humans decide to make a villain of a bird, it helps no end if it is sinister to look at and has a disreputable private life. The cormorant's sombre silhouette, its reptilian intentness, is matched to a domestic squalor at its nesting colony that even an ornithologist can find hard to excuse. Most cormorants nest on the coast or on maritime islands, but in Connacht they also find refuge on islands in freshwater lakes. In his Natural History of Connemara, Tony Whilde described how, over the years, a cormorant island becomes "a scene of utter devastation and desolation, with a smell to match. The vegetation is covered with murderous guano, and, at the height of summer, instead of being in full leaf the trees are merely bare and fragile skeletons." Eventually, the trees break and the cormorants desert their ruined islet, which can take many decades to recover.

Even on the substantial island of Lambay, north of Howth in Co Dublin, with its huge colonies of guillemots and other seabirds, the cormorants must add a special pungency to the cliffs in the breeding season. After a spectacular increase in numbers in the decade from the mid-1970s, the summer colony rose to well over 1,000 pairs, making Lambay the cormorants' biggest stronghold in Ireland or Britain. By the mid-1980s, the population of Irish birds was numbered at about 4,700 pairs.

A general increase in the species, extending across Europe, has brought a renewal of traditional hostility from fishery and angling interests. At last month's Dublin seminar on conservation of wild salmon, some participants were keen to indict the cormorant, along with seals, as a crucial predator in the salmon's life cycle. They would like to see an end to its general protection under the Wildlife Act.

This is the kind of concern that, in the 1980s, led the Wildlife Service to carry out a complete breeding census of cormorant colonies, and prompted fresh research into the birds' summer and winter diets. One of the most detailed studies of cormorant damage to game fisheries was carried out in Clew Bay, Co Mayo, for the Salmon Research Trust.

Working with a Zodiac inflatable among the jagged reefs and islands, Dr Ron Macdonald analysed the food of the cormorant nestlings within a 15-kilometre flight of the Trust's richly-stocked fisheries near Newport. He found that the main foods brought to the nest were freshwater eels and sea wrasse and that less than 10 per cent was the smolts (the young) of salmon, or sea trout.

At around the same time, two zoologists in Northern Ireland studied the diet of cormorants on the River Bush in Co Antrim. They found that some 260 birds were feeding on salmon smolts migrating to sea and that some birds ate a dozen at a time - but the scientists did not see this as any problem for the fishery management. Cormorants are opportunist feeders: the 113 tags from salmon smolts once found piled up in the guano of a cormorant colony in one Mayo lake may have been the residue from a few brief feasts.

Up to the passing of the Wildlife Act in 1976, the Republic had official bounty payments for the killing of cormorants: in the last three years before the Act, more than 3,500 were shot dead. Bounty payments are often an ineffective way of controlling predators - killing one just makes room for another - but cormorants do react to persecution, and readily desert their breeding sites. The current resurgence of the cormorant is fairly clearly linked to its protection.

The Irish bird is the large, "Atlantic" cormorant, Phalacrocorax carbo. The European bird, Phalacrocorax sinensis, is a smaller sub-species, the Continental "inland" cormorant. Thirty years ago it suffered a population crash, hit by persecution and pollution in its five main countries, and the EU gave special protection to its breeding habitats. Now it has made a remarkable recovery, to some 95,000 pairs, and has even spread to new countries, including inland waters in England.

The result has been enormous pressure for renewed control. In late 1996, 10,000 anglers demonstrated in Strasbourg against EU inaction, and last year the European Commission voted to downgrade the protection of the Continental cormorant. In the UK, the tabloid Angling Times ran a front-page picture of a masked rifleman on a river bank with a pile of dead cormorants, and the heading: "These Birds Must Be Killed".

The anglers' river-rage in these instances is not about salmon, or even trout, but about coarse fish such as roach and perch. In Ireland, too, these fish have become the main support of the cormorants living in winter on the inland rivers and lakes. In his studies for the Wildlife Service (now Duchas), Macdonald studied the diet of cormorants roosting on a wooded island on Lough Ramor in Co Cavan. These birds feed on the midland lakes with important brown trout fisheries, such as Sheelin, Derravaragh, Ennel and Owel. In the thousands of cormorant pellets he analysed, brown trout seldom occurred, and in late winter it vanished altogether. The silvery, red-finned roach was the birds' main food.

The rapid spread of this alien fish in Irish lakes and rivers has been due to anglers using it as live bait for pike, and to deliberate transfers between lakes with the intention of "improving" the fishing. In 1980, a few roach were found in Lough Corrib; two years later, more than 42,000 were removed from the lake. Perch, too, have multiplied explosively, especially in lakes where pike have been removed, and these now also help to feed the wintering cormorants.

Roach are the brown trout's direct competitors for food - even for the surface insects which give the anglers their opportunity - so their introduction has been at the expense of our highly-prized indigenous game-fish. The cormorants are thus doing angling a favour by reoccupying, in winter, what was probably their natural inland range.

As for the cormorants' appetite for salmon smolte, it is no bigger than that of brown trout in fresh water and many fish at sea. To no one's surprise, Ron Macdonald's conclusion a decade ago was that over-fishing by commercial drift-netters was the prime cause of salmon decline - a picture unchanged today.