Image caption Pine martens are thought to exist in parts of Wales, including Snowdonia and areas near Aberystwyth

Reported sightings of pine martens - a creature thought to be extinct in Wales - are being investigated.

The animal, part of the weasel family, was once common in the UK, but persecution and a loss of habitat led to its decline.

The Vincent Wildlife Trust (VWT) has received more than 40 unconfirmed sightings of pine martens, one of the UK's rarest animals, in the past week.

The VWT's work was touched on by BBC's Springwatch earlier this week.

Pine martens are about the size of a domestic cat, and are a protected species.

The BBC's Springwatch, which is based at Ynys Hir Nature Reserve in Ceredigion, has been following up sightings of the animal.

The VWT said it was going through reports of 50 sightings, 40 of them in Wales, in light of the programme's coverage of the animal.

We've no idea how many there are in Wales, but there is evidence they are persisting in small parts of Wales Lizzie Croose, The Vincent Wildlife Trust

The trust said pine marten numbers had grown in Scotland in recent years, but they had not recovered in Wales and England.

But it believes the animal does exist in Wales in Snowdonia, the Cambrian Mountains, in areas around Aberystwyth, and parts of Carmarthenshire.

The VWT's Lizzie Croose said research by the People's Trust for Endangered Species in the 1990s concluded that the pine marten was extinct in Wales.

"We've been working on pine martens in England, Wales and Scotland for about 15 years," she said.

"More recently, we've been working on a project called mammals in a sustainable environment, which has been examining why they are not recovering in Wales like they are in Scotland.

Image caption Pine martens were thought to be extinct in Wales

"We've no idea how many there are in Wales, but there is evidence they are persisting in small parts of Wales.

"Research by the People's Trust for Endangered Species in the 1990s couldn't find evidence of pine martens in Wales and declared them extinct in the country."

Ms Croose said the trust collected sightings of the animals and, over the years, had looked for droppings in the countryside.

"The last time we found pine marten droppings was in the Rheidol Valley, near Aberystwyth, in 2007," she said.

"We've had reports of a few sightings in the area around Aberystwyth and in parts of Snowdonia and Carmarthenshire."

'Kill game birds'

Ms Croose said there could be a few reasons why the animals were not recovering in Wales.

"It might be that numbers are so low in Wales that pine martens are not meeting to breed," she added.

"Perhaps the high level of fox numbers, (which attack pine martens), could be having an impact. There is research to show that pine martins have a similar diet to foxes and are attacked by foxes because of competition for food.

"Habitat destruction over the years could have also played a part, while years ago pine martens were persecuted because they were known to kill game birds and take their eggs. They were also killed for their fur."