Seen a white hare? Here's what you were looking at

ANOTHER LIFE:IT TOOK A COUPLE of days with loppers, bush saw and shredder to reduce the rampant escallonia bush outside my workroom window to something like an ordinary hedge. At my computer next morning I revelled in the long-lost view: a glowing Inishturk stretched out on the horizon, a small, neat inshore trawler unzipping a calm sea, right to left. But magically more, the rushy pasture beyond the hedge presented my first winter-white Irish hares.

The body of one was almost wholly white, with a dusting of silver-grey hairs on its back. Its face and the fronts of its ears were, however, the normal dark brown, as dramatic as a Halloween mask. Then appeared two more hares, their underparts also brilliantly white. In the mad March chasing and circling that ensued the whitest hare was my favourite to start boxing for a woman’s right to choose.

An icy winter must have produced more than the usual share of whitened Irish hares. Most books insist that they rarely undergo a winter colour change, unlike the Scottish or Scandinavian mountain hares. But the rarity may be just that of extremely icy winters. Recent weeks have brought several reports of white hares to Eye on Nature, all from the west. In Northern Ireland a conservation group called Irish Hare Initiative has mounted a white-hare survey. A map on its website (irishhare.org) shows almost 100 sightings spread across the island, clustered most densely in the midlands west of Dublin.

Occasional white Irish hares have been reported for well over a century. In the late 1800s the eminent but ageing naturalist Alexander More noticed, while being pushed in his bath chair through the streets of Dublin, “that after only a week of snowy weather about the middle of January, the number of hares hung up in the poulterers’ shops showing these light patches become conspicuously greater than they had been at the beginning of the month”. Today, as the mammalogist James Fairley sums up, “In a given area it sometimes happens that some will turn almost completely white, others will be half-and-half and still others may only whiten a little or not at all.”

Lepus timidus hibernicusis a race of the Arctic hare. On an expedition to northeast Greenland, to help David Cabot ring barnacle geese, I was charmed by the scores of fluffy, snow-white animals, surreally nibbling at yellow poppy flowers in the midnight sun. They could not have been more conspicuous on stony hillsides thawed out for the summer, their leverets an easy target for any passing raven or gyrfalcon. But, in the numbers game of natural selection, the year-round whiteness of High Arctic hares has to benefit the population as a whole.

As much as for camouflage in snow, the whiteness of northern animals and birds seems to relate to temperature: the farther north, the whiter they tend to be. Like the cells of the polar bear’s white fur, or those of the feathers of the snowy owl, those of the white hare are filled with air, an insulation that reduces heat loss from the body.

The winter whitening of mountain hares in Scotland and other northern countries is achieved by a third moult of the year, beginning in October and perhaps partly triggered by the shortening length of day. Fine but dense hairs, empty of the usual melanin pigment, are projected to take the place of the brown ones, producing an often strikingly sudden change of colour. In Ireland it has been generally supposed that there are only two moults, so that genetic control of pigmentation remains something of a mystery. Some observers have reported hares with white patches outside the winter season.

Our subspecies of Arctic or mountain hare is not called hibernicus for nothing. Indeed, research by the Quercus conservation unit at Queen’s University Belfast has suggested enough genetic divergence from Scottish or other races to warrant the animal’s promotion to a full species.

As a survivor of Ireland’s last ice age, it may even link, uniquely, to a former species of mountain hare once common in Europe. Today its most obvious distinction is its island-wide distribution, right down to the edge of the sea, together with the widely remarked “rarity” of whitening in winter.

Exceptionally low temperatures in the last two winters or the extent of snow on the ground may have triggered a third, much later moult in many Irish hares. In his last book on Ireland's furry animals, A Basket of Weasels(2001), James Fairley found that this possibility "apparently has never been explored" . A systematic study of winter whitening was, he thought, "long overdue". The map at irishhare.org, constantly updated with fresh reports, could offer some raw data to begin with.

Eye on nature:

I hung out two bird feeders in my backyard in early February, but only one bird has appeared, and I rarely see small birds flying around, although there are blackbirds, thrushes and sparrows on the lawn. Has the harsh winter killed off the small birds?

Eamonn Cusack, Terenure, Dublin 6

If you waited until February to put out the feeders the small birds may have moved to neighbouring feeders during the earlier hard weather.

On a rock in west Cork I was attracted by a bright red top on what I think was a short-stemmed lichen among mosses, sedum and grass.

Gillian McCormack, Ballydehob, Co Cork

It was Cladonia bellidiflora, from the photograph you enclosed. It is known as matchstick lichen and is found in coastal areas.

In December 1992 you published a letter in Eye on Nature from our seven- and five-year-old daughters, Emma and Ruth, about avocets at Bull Island, in Dublin. The occasion was the unveiling of a plaque to Fr Kennedy SJ, the great Bull Island birdwatcher. As a result a lady called Ruth, living on Waterloo Road, sent a copy of Kennedy’s An Irish Sanctuary to our Ruth, who today is more interested in birds than she might have been if that letter had not been published.

Frank Turpin, Percy Place, Dublin 4

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