The raven resurgent

A peak of reckless pleasure in the life of our small black dog is to swim the channel to the strand, make a racing circle or two to warm herself up, and then take off at full belt after seabirds. Her pursuit of gulls, oyster-catchers, diminutive sanderlings is futile but impressive: somewhere in a curiously scaled-down mix of labrador and spaniel is a gene for phenomenal speed - not the greyhound's pumping pistons but a flowing, skimming gallop that scarcely marks the sand.

Whatever the gulls and waders think of this intrusion, one bird may even take pleasure in it. A solitary raven is frequent at the corner of the dunes, perching now and then at the tideline, and I watched with some apprehension as Meg shot away towards it: this, after all, is a powerful bird that will harass an otter for its fish. But it lifted just above Meg's reach and retreated in a teasingly slow flight to the dunes, landing and rising until the dog gave up. Left to themselves, their games might become more elaborate.

Actually, these days there are half-a-dozen ravens hanging about in the dunes, and one does not have to wade far through the marram to find a reason: a dead ewe on her back in a blizzard of wool, entrails pulled out on the moss. This is going to be a raven's winter all over the western sheep country.

From our breakfast-table we watched a flock of sheep being driven past our gate towards an outfield nearer the mountain. The ewes, cheerfully dabbed with fresh red dye, seemed an endless, jostling procession until dog and farmer finally appeared at the rear. With the market for hill lamb in collapse and the Government under pressure to get sheep off the overgrazed mountains, the flood of red-splashed fleeces past the gate seemed prophetic. In Shetland, they are "culling" sheep in thousands and burying them in mass graves.

The Government has until next July to show the EU auditors some real progress in reducing hill-sheep numbers under the REPS scheme. Some 40 teams of experts, one agriculturalist and one environmentalist in each, are out on the mountains, moors and coasts, drawing up the plans for sheep reduction on all the threadbare commonages: the Department of Agriculture and Duchas working on the same side at last.

In the interim, the REPS hill farmers are losing their premiums on almost one-third of their ewes. They were to be paid for killing them, but the EU wouldn't agree. Instead, the factories will be paid £10 a head for accepting 206,000 of the scrawniest ewes, while the farmers get a £9 a head top-up towards the fodder for the 480,000 sheep they will keep on their farms.

It will be a difficult winter, and the ravens, as I say, will get their share of carrion. Earlier in the autumn, climbing through the rocky fields towards the ridge, I came up with a flock of "crows" that I had taken to be rooks and suddenly realised were ravens - 22 of them. They could have been a floating group of non-breeding birds, or a flock made up of the young of several families, including those of the resident ravens that nest in a cliff beyond the lake.

The huge rise in sheep numbers over the past two decades helped to raise Ireland's breeding raven population to about 1,000 pairs and to spread them from their refuges in the mountains and on sea cliffs to nest in the lowlands, in quarries and trees. But this could also be seen as a recovery for the species, which was almost wiped out in many areas only a century ago.

In the 1700s, ravens ranked high among the venerated scavengers of cities. But by the start of the 1900s they were actually rarer in Ireland than the peregrine falcon or the chough. Shepherds and gamekeepers had used gun and poison to drive the ravens from most of their inland breeding-places, such as cliffs over rivers and tall beeches in the big demesnes, and the birds were forced to the island's hilly perimeter.

In modern times, the planting of bogs with conifers might, in theory, have reduced the ravens' scavenging-territory, as it did in the great blanket forestry of Scotland. In practice, the fragmented forests of Ireland have provided new nesting sites within easy reach of sheep carrion and an extra supply of mice and birds' eggs from plantations in their early years. But even where the food supply is exceptionally good, the ravens prefer to keep their nests at least a couple of kilometres apart.

It is this territoriality, played out in the many chases and squabbles I watch above my garden, that ultimately spaces out the raven pairs and puts a limit on their overall numbers. Derek Ratcliffe, author of the most recent natural history of the species in Britain and Ireland (The Raven, Poyser, 1997), feels that the birds do, over time, space themselves out to match their own perceptions of the amount of food available.

Every book of this sort has to have a chapter on raven intelligence, since human perception of what the Victorians called "sagacity" in the species has been current since Pliny and Thucydides. Konrad Lorenz kept the birds to study and considered them to have "the highest mental development of all". Unfortunately, his collection of anecdotes were no more valuable as evidence than those of any other raven-fancier, and Ratcliffe is just the latest writer to urge "careful experimentation of a rigorous, scientific kind".

The best observations I know are found in Bernd Heinrich's Ravens in Winter (1989), an engrossing account of his work with ravens in the snowy woods of Maine. He tells of a raven chiselling a groove around a corner of a chunk of suet, apparently to break off this larger piece; and of another bird who hacked off bits of a frozen carcass and stacked them in a pile, ready for air-freight in its bill.

It may not sound much - but it's more than Meg can do.