Squirrelling away knowledge for a rainy day

Some of the happier younger schoolchildren in Northern Ireland are out in the autumn woods just now, pretending to be red squirrels. Each is given three nuts from the teacher's bag and has 20 seconds to bury them where their fellow squirrels won't discover them. Later on in the day, they get 20 seconds to find them again.

"The difficulty in finding them can be discussed," suggests the teacher's education pack, "and the effect on squirrels if nuts were lost; whether anyone pinched other squirrels' nuts, and the potential problems of hiding them all in the same place . . ."

There are other games, where some children pretend to be trees, to show the problems for red squirrels when their habitat disappears. Teacher pretends to be a businessman interested in building a car park or office block in the wood. The "trees" are felled one at a time while the squirrels are running around, so that each time they try to find a tree to nest in, there are fewer and fewer available.

Thus are the sympathies of small children enlisted to conservation. The older ones explore ecology factually, bringing map-reading and bar graphs to the story of the red squirrel's threat of extinction in competition with the grey. The latest research in the North (some of it by UCG's Donncha ╙ Teangna) helps children decide the best ways of saving the red.

There is something touching in the choice of the squirrel to inspire not only this excellent new pack for schools but also a vigorous conservation strategy, with a potential pay-off decades in the future. It also helps, of course, that the squirrel was one of the threatened mammals highlighted in the UK Action Plans for Biodiversity produced six years ago (the Republic has still to catch up on all the promises made at Rio). While Ireland's reds may be more secure than the populations in Britain, their future seems inevitably at risk from the relentless spread of grey squirrels. Preventing their extinction will mean introducing a kind of apartheid between the two species.

Since their introduction to an estate in Co Longford 90 years ago, the American grey squirrels have spread extensively through eastern Ireland, typically moving outwards at about 3km a year. The reds are still settled to the west of the Shannon, across most of Munster and south Leinster, and in patches of the Glens of Antrim. Even in Dublin, they can still be seen in urban trees, as in the National Botanic Gardens and St Anne's Park.

The two squirrels overlap in large parts of the southern midlands and the border counties. They may co-exist for decades: they seem, remarkably, to have shared some hazel-ash woodlands in Co Fermanagh for 40 years. But the usual pattern is a much more rapid disappearance of the resident reds, especially in mixed woods where oak trees have supplied much of their food.

Precise reasons are subtle and still uncertain. The greys are much bigger, more prolific and aggressive. And while both squirrels have a remarkably broad appetite, from seeds and bark-sap to tree-flowers and caterpillars, the greys have one big advantage in broadleaf or mixed woods. Native to deciduous woods in North America, they possess a digestive enzyme which lets them detoxify acorns (the reds can eat these only when quite ripe). In mixed woods in autumn, the greys compete for the hazelnuts and then go on to monopolise the acorns. And because they spend much more time on the ground than red squirrels, they probably find most of the food the reds have hidden away in scattered caches.

The original post-glacial red squirrels in Ireland probably lived mainly in the upland woods of Scots pine, birch and yew. As the native pines died out with climate change, they adapted to lowland broadleaf forest, only to lose this to clearance during the 1700s, by the end of which they were reckoned extinct. Today's reds have descended from squirrels reintroduced from England in the 1800s.

Under pressure from the greys, the reds survive best in large tracts - at least 2,000 hectares - of conifer forest in which a mixture of tree species guarantees them a supply of seed. The small cones of Sitka spruce, still the staple species of Ireland's commercial forests, release their seeds in autumn, but the addition of Norway spruce, Scots pine and larch provides bigger cones and a sure seed supply for longer.

These and other conifers are now being planted in up to 20 per cent of the four big conservation zones, in east and west Fermanagh and in east and west Tyrone, set aside by the North's Forest Service as red squirrel refuges.

In the core areas, there is a halt to planting large-seeded broadleaf species such as oak, sycamore and beech, which would attract the grey squirrel. These are replaced by birch, rowan, ash, willow, aspen and alder, all of which have seeds relished by reds. Greys tempted in by the Norway spruce are controlled by trapping and shooting.

In the Republic, 70 per cent of new plantings in Coillte's forests are still Sitka spruce, and the company's commitment to greater diversity and mixed stands has yet to convince all of its critics. During the 1990s the total share of Norway spruce in its new plantings rose to 10 per cent, with larch close behind.

Survival for the red squirrels in the west and south has to be planned for now, against the inevitable advance of the greys. Specific forest design will be needed to guarantee a number of upland refuges and buffer zones, each large enough to support a viable population, and linked by conifer corridors to keep the genes of the species circulating.

In our new upland millennium oakwoods, too, random stands of Scots pine - among the most beautiful of conifers - could recreate a bonding of squirrel and tree not seen in Ireland for centuries.

The education pack Red Squirrels in Northern Ireland was prepared by Michael Conway, Environmental Educator, Roe Valley Country Park, Limavady BT49 9NN (e-mail: Michael.Conway@doeni.gov.uk). It can be accessed through Environment and Heritage Service's website: www.ehsni.gov.uk