Wild boars raise question of nationality

ANOTHER LIFE:AMONG THE wildlife desperately foraging for food in Ireland's icy New Year landscape were unknown numbers of Sus scrofa, the wild boar of Europe. Recent sightings and shootings have confirmed a quite widespread presence of the animal in Leinster and elsewhere, including whole families with piglets (or shoats). They began as escapes from farms, or perhaps were let out by animal-rights saboteurs as has happened notoriously in Britain, where some feral colonies are now well established in remoter woodland.

Rooting for insects in leaf litter or in soil under snow, munching dead birds, or raiding the odd stand of brussels sprouts, wild boar are omnivorous eaters. With only coarse, hairy coats, however, they cannot put up with extreme cold for long –­ only the biggest, fittest animals survive the Russian winter. Those that have come through our more modest freeze-up now face a determined campaign to rid the island of its latest introduced alien.

Invasive Species Ireland, backed by environment agencies north and south, is really quite worked up about wild boar, counting them as “major drivers of ecosystem change”. With no natural predators, “they would expand unchallenged, [uprooting] large areas of land, eliminating native vegetation and spreading weeds.” The shooting of a 180kg boar near a school in south Tipperary has also encouraged concerns about public safety.

Wild boar were, of course, a prime food source for Ireland’s first people, the Mesolithic hunters. The UCC mammalogist Paddy Sleeman has calculated that, based on densities of wild pigs in modern day New Zealand, there might have been 844,210 of them on the island. On present evidence, they went extinct in Neolithic times, harried by hunters and up to 1,000 wolves, but mainly, probably, through loss of habitat as Neolithic farmers cleared the forest.

I find this in a fascinating overview of Ireland’s land mammals put together by Dr Sleeman, with Dr Derek Yalden, president of Britain’s prestigious Mammal Society, and Pat Smiddy, the Cork naturalist. It appears as a chapter in a recent book of papers honouring UCC’s Prof Peter Woodman, the archaeologist whose work has done so much to illuminate the early history of our human settlers and wildlife.

Just how Ireland got its land mammals has been highly controversial, prompting research that has overturned some popular assumptions. The red deer, for example, long thought to be a native species, was probably introduced in Neolithic times. The picture favoured at one time by the late Prof Frank Mitchell, in which animals “hurried to reach Ireland” across a land bridge, is being replaced by the major role of introductions, accidental or deliberate.

Only the stoat, otter and hare keep their firm credentials as cold-tolerant natives, surviving the cold snap of the last ice age at the south of Ireland or nearby “Celtic lands” now flooded by post-glacial sea rise. The rest of our mammals were probably early introductions from the European mainland and later ones from Britain.

Genetic research shows, for example, that Irish pine martens, cold-tolerant and long assumed to be native, are not closely related to Scottish martens but have come from further south, probably brought from France or Spain to breed for their fur. Even the fox might have been introduced for fur: the archaeological evidence is equivocal. The red squirrel may have become extinct and then been introduced, but was it ever native? Squirrels west of the Shannon show signs of being genetically distinct from those in the east. The alien grey squirrels, one is happy to learn, are not cold tolerant, so the big freeze may have reduced the numbers driving out the eastern reds.

There are more surprises in the roster of population estimates for our mammals, past and present, calculated from all sorts of evidence and extrapolation from densities in the UK. The biggest, perhaps, is a new figure for the number of the island’s badgers – not 250,000, but 100,000, according to recent studies and not arising from the culls in TB clearance areas.

There are great contrasts in numbers of similar mammals with different habitat needs. Even field (wood) mice can’t live in Arctic cold, but, judging by British densities, we have 13 million of them, compared with perhaps 100,000 house mice. There are clues in their genetic variation, and fleas, to keep a question on their origin.

Hedgehogs were introduced, perhaps for food, or for carding sheep’s wool with their spiny skins. There may be 712,000 of them – safer in urban areas than near badgers, which eat them.

Eye on nature

On New Year’s Day in Monivea Woods in Galway, I came across what appeared to be hair-like frost sculptures, like candyfloss, on dead, barkless, beech twigs. It melted when touched.

Claire McLaughlin, Abbeyknockmoy, Co Galway

That was hair ice. It grows on bare dead wood, outward from the surface of the wood, as super-cooled water emerges from the wood, freezes and adds to the hairs from the base. A rare occurrence in these islands.

Why, for the second year in succession, have we had no greenfinches visiting our bird feeders? Goldfinches and siskins are also absent.

Sean Morgan, Abbeyleix, Co Laois

Greenfinches are dying from trichomoniasis, caused by the parasitic trichomonad organism. All birds have suffered but greenfinches have been most affected. The parasite blocks the bird’s throat, killing it by starvation.

Stop feeding sick birds immediately, clean all bird baths and feeders and move them to another part of your garden.

Michael Viney welcomes observations at Thallabawn, Carrowniskey PO, Westport, Co Mayo. Please include a postal address. viney@anu.ie.

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