Tiny kingdoms scatter after summer

THE mice are back in the house again, so it's definitely autumn: squeaks ring out as the new crop of males decide which is boss. We go around setting traps that haven't been used since spring. With so much food to choose from on the acre seeds rattling down every where like muesli from heaven - what draws them back to a boring, and ultimately fatal, diet of dog biscuit?

Hardly temperature alone, for this week's no colder than last. And yet it is autumn: an extra depth to the silence of a still day, a subtle but definite change in the angle .between the mountain, the sun, and me. Something of this sort, perhaps, or some critical point in the length of day, helps to nudge Mus musculus indoors.

I'm out digging, making beds for a new herb garden. Beside me, the hawthorn hedge glows a coppery red, its glistening berries almost formally arrayed, as in a medieval tapestry. Chew three berries a day for the rest of your life, says the herbalists, and your heart will thank you for it. Your palate, alas, will not: a pulpy, nothing taste, a pit for spitting out to make the robin jump.

Everybody should be out digging on sunny days in September. There's something infinitely restorative and good for national morale in the thrust and turn of a spade (Chairman Mao and Pol Pot overdid things). As for making a new garden - a place with an entrance and a path right round here and a circular whatsit in the middle, this is surely what one was born for.

Remove all perennial weeds - very well. In light, sandy loam a root of couch grass travels forever behind a point that pierces potatoes, even wood. Roots of mare's tail spring from brittle, black Internet, deep underground, that connects all mare's tail, everywhere. Silverweed adds grapnel at the surface to a conspiracy of cables underneath. Beside these, the resistance of docks or nettles even briars, is simply and honestly overcome.

One meets the soil's wildlife, of course, its world suddenly riven by an earthquake, tunnels collapsing, basements bared to the light. Lumbricus terrestris, king of worms, is reburied at once, with apologies. Centipedes race for the dark: almost anything fast moving, in our temperate soils, is a predator on plant chewing invertebrates and thus the gardener's friend. A clutch of great white grubs, of the sort a hungry Aborigine might savour, are the larvae of the cockchafer beetle and are left to squirm and catch the robin's eye.

It's the ants I feel sorry for. Occasionally, mowing a stretch of old pasture, I slice open a shallow mound which is the home of lasius flavus, a yellowish brown and common in the west's grassy places. There is great turmoil in the shattered nursery chamber as worker ants snatch up the larvae and pupae and carry them to safety at deeper levels in the nest.

THE scene is not as chaotic as it seems; each ant knows what it has to do. Crumb by crumb," says Michael Chinery in his Natural History Of The Garden, "the disturbed soil is rearranged and new chambers are hollowed out: in a day or so, you would not know that anything had happened."

The black and red ants of Irish gardens seek out the heat storage of concrete paths and paving stones and make their nests beneath them. To the yellow pasture ants of Mayo, the dry, sun warmed soil of the old raised beds I'm reshaping were promised ground in which to found new colonies.

One jerk of the spade breaks a nest into fragments, its tunnels and chambers dissolve past any reassembly. When this happens I feel the need to leave the scene for a while, unable to bear the reproach of all that desperate scurrying and carrying.

The Atlantic coast has, I suspect, far fewer ants than other parts of Ireland. Lean soils, poor in humus, lack the range or insect life that enriches their ideal world.

A favourite food is honey dew, the excess sugar excreted by aphids as they feed on plant sap: the lower leaves of trees such as lime and oak are often quite sticky with it. Ants "milk" the aphids by stroking them with their antennae and licking off the sweet drops they exude. They even build "cattle sheds" around the lower stems of plants, to protect the little homoptera from predators and bad weather.

Aphids tend to be far scarcer on coasts with a prevailing ocean wind, and this may partly explain smaller ant populations. Certainly, in all these years, no marriage flight of ants on a hot summer afternoon has been dense enough to catch my eye. In the east, by contrast, the swarms can blacken windscreens, and flights of black garden ants rising high above Dublin bring swifts and black headed gulls to feed.

There's so much to be said about ants and their social organisation that serious books about them are often big and expensive. But there's now a good paperback in the popular Whitet wildlife series: Ants, by Dr Ray North, is lively reading.

This is the weekend of the Irish Birdwatching And Wildlife Fair at the Oxford Island Nature Reserve on Lough Neagh. The programme today and tomorrow offers wildlife walks, bird watching cruises on The Maid of Antrim, workshops on moths and bats and wildlife gardening, and special activities for children. Oxford Island is on the southern shore of Lough Neagh, a few minutes drive from junction 10 on the M1 from Belfast to Dungannon.