Breaking the bank vole mystery

ONE of the mysteries of Irish natural history has finally been solved and the solution is rather an elegant one. We now know how and when bank voles got to Ireland.

Bank voles were first positively identified in this country in 1964 from specimens found near Listowel in north Kerry. Today they are only found in the southwest, roughly speaking below a line drawn on the map connecting Waterford with Galway. But they are spreading quite rapidly north-eastwards.

One study suggests that the rate of their advance is up to 4km a year, which seems very fast for such a small animal. Bank voles only have a body length of about 10cm, plus a shortish tail.