Silence broken by sound of choughs

In the delicious autumn silence that settled on the hillside last week, the contact calls of a flock of choughs - chee-ow! chee-ow! - were ricocheting among the rocky creggans behind the shore. This is their favourite playground when breeding is over: I meet them dancing in an updraught where the sea breeze bounces off a bluff or a low cliff, rising and falling and tumbling in the air with their glossy wing-tips spread.

It is also the choughs' feeding ground and winter larder. Here, in the leaner months, I find every cow-pat in the dunes flipped over and teased apart for grubs and beetles, whole grassy slopes stabbed with hundreds of holes where the birds have probed the thin soil (for leather jackets) with their curved vermilion bills.

The chough was originally a crow of mountain-tops and it still likes to nest in caves and remote rock crevices. But for food it has adapted to a varied, modest diet shaped by some kinds of, equally modest, traditional farming.

It likes, in particular, a natural but closely-grazed grassland that lets it hunt for grubs in the soil. The thin, rough turf of Atlantic coasts, grazed by sheep and rabbits, is ideal. Dry stone walls, full of earwigs and spiders, and earthen field banks, full of ants, add to its diet. Cattle in low numbers scatter not only their cowpats but seeds from hay and silage.

The chough thrives, in other words, at the margins of pastoral agriculture, often in territory with a particular cultural resonance (it was striking that the recommendations of a key conference on "Choughs and Land-use in Europe" were printed in Irish and Scots-Gaelic, Welsh and Basque, along with more predictable languages). If the chough disappears through change in its habitat, it will, one senses, be more than a bird that is lost.

The species has had steep declines in the past, often to do with human persecution. It is extinct in England, and in Ireland retreated from the eastern counties during the late 1800s. Some of its modern troubles also have to do with human pressure (choughs let tourists to within 30 metres, before flying off) but the serious declines have resulted from changes in their habitats.

Ireland generally is the choughs' best stronghold in Europe. The last survey, five years ago, found more than 900 pairs, concentrated particularly along the cliffs of Kerry and Cork. But at the opposite end of the island, along the coast of Antrim, the last few choughs are threatened by just the sort of changes that have wiped them out in most of Britain and southern Europe.

Ten years ago, there was a "relatively stable" small population of four or five pairs of choughs on Rathlin Island and a similar number spread out along the coast between Giant's Causeway and Fair Head. Today, the choughs are gone from Rathlin (along, it is feared, with the last pair of corncrakes, which did not return this year) and just three pairs of choughs survive on the mainland cliffs, only two of which bred successfully this summer.

Much of the original clifftop grassland has been reseeded, to feed larger numbers of sheep, and in some places the sheep have been fenced off from grazing difficult slopes between the cliff-tops and the shore. Both changes have produced more rank vegetation, which interferes with the way the birds feed. They use visual signs in the soil to tell them where insect grubs can be found, and thick grass and long herbage cover these vital clues.

To try to salvage the situation, the Royal Society for the Protection of Birds has been worked with the North's department of agriculture to devise a "chough option" for preserving habitat in farm management plans in the Environmentally Sensitive Area scheme which covers the Antrim coast and glens and Rathlin Island. Essentially it means paying farmers to leave the wild grasslands alone, and allow the sheep to graze it wherever they can reach. But the RSPB also visits the farms to give specific advice on grazing regimes so that choughs can be sure of their leatherjackets in late winter and early spring.

Across the North Channel from Rathlin, the Scottish stronghold for choughs is the Hebridean island of Islay (pronounced Eyelah). Eric and Sue Bignal, who farm in Islay, have been studying choughs for 17 years and have colour-ringed some 850 nestlings in order to track their behaviour. They have come up with some important insights into the birds' social life*. Without a flock for the young choughs to live with and learn from, it does seem unlikely that Antrim's last pairs can survive for much longer.

When fledgling choughs are about two months old, their parents take them "to school", as it were, enlisting them in a nearby flock, mostly made up of young bachelor birds. They stay with them, feeding them for two or three weeks, then leave them to fend for themselves in the flock. This is where the young birds learn their survival and foraging skills and form, in due course, their affectionate pairs, to breed in their third year.

The parents, meanwhile, go back to their home range, socialising with neighbouring pairs (choughs may still be breeding at 13 or 14) and occasionally revisiting the wandering sub-adult flocks which now include their fledglings. "The older choughs learnt what they know from their predecessors," say the Bignals, "and each new generation is heir to generations of evolving chough wisdom." In particular, this social behaviour passes on the regional specialisms in feeding behaviour and food items.

The loss of the flock, therefore, is usually the beginning of the end, even though individual pairs go on breeding and producing young, as they did for a while on Rathlin and are still doing on the Antrim cliffs. It gets to the point where the birds are too few even to decide which of them should keep watch for the peregrine or ravens - or farmers bearing fencing stakes and wire.

*See British Wildlife, Vol 8, No 6. Subscription address: Lower Barn, Rooks Farm, Hook, Hants RG27 9BG.