Kingdom for a deer

At this point in October you would swear the hillside rowans of Connacht knew just where to stand for the sun to catch their berries to best effect: such a singing vermilion against the first sharp shadows of autumn.

This is another great year for berries. I browse along the brambles of the drystone walls, handing down a share, one by one, to the dog, who is quite as fond of blackberries as any fox or badger would be.

I am sorry not to be in Co Kerry, to see what sort of crop the strawberry trees are bearing, for this is another tree that knows how to pose, among rocks on a mountainside or leaning out over a lake. Arbutus unedo looks its best in October, when clusters of creamy, bell-shaped flowers hang alongside last winter's berries, ripened, at last, to red.

Their textured skin is somewhat like a strawberry's, but, as Terry Carruthers reminds us in his new book Kerry: A Natural History (Collins Press, £29.95), the unedo bit of the tree's Latin name is derived from unum edo - I eat only one. The fruits are insipid and no kind of feast.

Arbutus is just one of the exotic rarities which makes Co Kerry well worth a natural history book to itself. The tree belongs in southern Europe, where it grows as a shrub among the maquis, and it is so sensitive to frost it could not possibly have survived the last glaciation in Ireland.

But it arrived so soon afterwards - probably in the droppings of birds - as to earn its naturalisation and an early name in Irish, crann caithne. It was a lot more abundant in the past, probably in the spread of secondary forest, and could become so again, as global warming takes hold.

There are several reasons why Co Kerry should be, as Carruthers says, "biologically the most interesting county in Ireland". It is wrapped around by the ocean, and thus by winter warmth and a constant, high humidity. The surge of the Atlantic brings an exceptional crop of plankton and fish to feed the huge summer colonies of seabirds on the islands - gannets, storm petrels, shearwaters, puffins and the rest.

Inland, the highest mountains in the country shelter the biggest remnant of native oak forest in Ireland and the last pure reservoir of native red deer. And because of the mildness and steady humidity, the oakwoods are one of Europe's richest sites for Atlantic ferns and mosses. Along with all this comes the celebrated "Lusitanian" species, such as natterjack toads, the spotted Kerry slug, the Arbutus, and the sumptuous flowers of the butterwort on the cover of Terry Carruthers's book.

Exactly how these plants and animals arrived in Co Kerry could have supported a whole chapter of argument over landbridges, rafting, or early introductions by man. Carruthers decided, possibly wisely, to take all this as read, and to talk about the species in a way the ordinary reader can enjoy.

He tells us the voice of the natterjack toad "is among the loudest and most strident animal noises to be heard anywhere in Europe", which is something of a putdown for the red stags roaring in the valleys just now.

Carruthers has worked as a park ranger in the Killarney National Park since 1981 and his strongest personal interest is in birds. Patient watching in the mountains has rewarded him with the scarce ring ouzel (like a blackbird, with a white bib). He has also observed the appetite of Killarney's sika deer for the semi-digested droppings of the Greenland white-fronted geese: "They will actively approach a flock of geese on a bog and forage among the birds exclusively for droppings: the ultimate hot snack!"

The introduced Japanese sika deer once substantially outnumbered Co Kerry's native reds. In the 1970s there were upwards of 1,000 in the Killarney Valley and their grazing in the national park did a great deal of damage (in particular, to the trees in Europe's oldest yew wood, on the Muckross Peninsula). A heavy culling in the 1980s has reduced their population to about 700.

Do sika breed with the red deer, as they have in Co Wicklow? No hybrids yet, says Carruthers, but escapes of continental red deer and fallow deer imported for farming seem certain to develop wild deer herds in Co Kerry which will threaten the purity of our native reds. Meanwhile, the county's sika have their own special importance as one of the purest strains of the species anywhere in the world.

This is a thoughtful sampling of the wonderfully diverse natural world of Co Kerry, well shared out between land and sea and across the whole range of lifeforms. It steers clear of easy distractions (Fungi at Dingle gets his paragraph, no more) and a bonus for researchers is the diligent bibliography - nearly 1,200 references - on the pattern set by Tony Whilde in his Natural History of Con- nemara.

Across the island, the coastline of Co Dublin sets a crumbling, sometimes tortuous boundary to the Pale. Michael Fewer walked it, starting at the Meath border and ending in an obscure ravine on the northern fringe of Bray. He has borrowed a phrase from Finnegans Wake, "By Swerve of Shore", for the title of his latest traveller's tale (Gill & Macmillan, hardback, £12.99), a splendid successor to his "walk" books from Waterford, Wicklow and elsewhere.

It was an odd sort of journey, weaving in and out between the natural world of seals and birds and sea shells, and a human one that, aptly, seems to be fraying at the edges. Fewer, an architect, sifts through a palimpsest of overlapping pasts - grand ruins, little churches, fishermen's cottages and pubs - and his artless reporting has moments of surrealism.

People still hide away at weekends in cherished railway carriages, still fish for bass in a crashing surf, their backs to the world. But vandals will soon make a bonfire of your little dacha on the shore, and the Forty Foot seems to have gone gay.