Hungry and merciless, Devon's killer dormice decimate rare bird colony

They are tiny, sleepy and weigh no more than three pound coins. But though one of the cutest of wild creatures, the dormouse is now being seen as a cold-hearted killer.

Though they habitually snooze for two-thirds of the year, it appears certain dormice, for the rest of the time, have been munching away at a rare colony of pied flycatchers in Devon, jeopardisinga strikingly successful 30-year scheme to establish the birds in Okehampton.

The birds, rare in Devon, are finding their nests taken over by the rodents which then go on to eat the eggs. Yet because dormicethemselves are rare nothing is done to curb them. Under the 1981 Wildlife and Countryside Act, a licence is needed just to touch one.

Gordon Vaughan, chairman of the Devon Birdwatching and Preservation Society, has spent the past three decades encouraging pied flycatchers with more than 200 bird boxes placed around the town.

In 1970, when Mr Vaughan's campaign began, there were only 20 pied flycatcher pairs in Devon. By 1989, 68 pairs were nesting in the town alone. But then the dormice – whose numbers had plummeted by 95 per cent over the past century – started their own recovery plan. Mr Vaughan found them emerging from hibernation just after the birds had flown in from Africa and laid their eggs. "Squatting" the nests, the mammals would eat the eggs; in tussles, the three-inch long dormice "invariably won". Over the years the flycatchers' numbers dropped.

But there are signs of apeace process, as property disputes give way to timeshare schemes. Some of the flycatchers raise young, depart – and then the dormice move in. One nest has even produced 24 young – 14 fledglings and 10 dormice – in a one year.

Mr Vaughan notes the amazing instances "of recorded dual breeding".