Stop the greys' western march

Just to remind readers of their continuing spread, last year marked 100 years since their introduction. In 1911, six pairs of breeding greys were released on the Castleforbes Estate in Co Longford.

Since then, the species has expanded in all directions, except westwards, where the River Shannon had appeared to form an obstacle. However, some unverified sightings have been recently reported in western counties.

As their populations have increased, we have seen a marked decline in the numbers of our native red squirrels, and studies haves shown that reds tend to disappear from an area within a decade or two of the arrival of the grey.

Greys carry the Squirrel Pox Virus (SQPV), which is lethal to the native reds, and there have been two cases of SQPV confirmed in Co Wicklow.

Red squirrels are now completely absent from Meath and Westmeath and are rare in the counties of Louth, Carlow and Kilkenny.

One well-known fact regarding greys is their ability to store large quantities of acorns in preparation for the winter.

But what is not commonly known is that, prior to burying each acorn, they bite out the growing tip. This kills the acorn, preventing it from germinating. On the other hand, jays bury them unharmed, thereby ensuring that the acorns they forget to retrieve will grow into new oak trees.

Another fact is, like most game species, the grey squirrel is considered a delicacy in America, yet here in Ireland it has never been properly considered as a food source.

In Britain, it is often on menus and one enterprising restaurant owner even advertised roast squirrel as "flightless grouse" to encourage his customers to try it out.

Grey squirrels can eat their own body weight (about 1.5lb) every week and along with stripping the bark from young trees, they eat root crops on farms, fruit from orchards, raid bird tables in parks and gardens while digging up flowering bulbs and attacking songbirds nests where they eat both eggs and fledglings.

Buzzards and pine martens are also increasing in number and have expanded their territories. Pine martens had been hunted almost to the verge of extinction but are now benefiting from the increase in conifer woodland. Along with the buzzard, their presence is thought to be reducing the numbers of greys.

However, like mink, pine martens can also contribute to a fall in the numbers of free-range ducks and chickens.

We are all now being asked to report sightings of squirrels "dead or alive" on both sides of the River Shannon, as part of the new study focusing on the spread of grey squirrels to the west of Ireland. Sightings can be easily recorded on a form at www.woodlandmammals.com.

Hard copies of the form are also available on request from the Mammal Ecology group at NUI, Galway (091 492903 or 087 1867664). Sightings can also be reported to Dr Michael Carey, forestry and management consultant, Furze Lodge, Newcastle, Co Wicklow. Email careyml@eircom.net or call 087 2381060.

The help of the public will be vital to the new study as local knowledge is essential for ecologists undertaking a species mapping project.