Image copyright Rob Browne / Media Wales Image caption Squirrels which have put on weight due to the mild weather have been spotted around Cardiff

The mild weather this winter has benefited wild animals across Wales, a BBC nature presenter has said.

Iolo Williams said squirrels, mice and birds were putting on weight due to increases in acorn crops, fungi and other food sources.

But mild, wet weather could also see higher death rates in animals like otters, which leave rivers to search for food on land and end up in roads.

"It's been a very odd, unusual year," he said.

It comes as fatter squirrels have been spotted in Cardiff - but Mr Williams said it was not unhealthy for them to put on weight because they would self-regulate.

Image copyright Rob Browne / Media Wales

"In some areas it's been a good acorn year, which helps [squirrels] a lot, in other areas it hasn't.

"There were a lot in Bute Park [in Cardiff]. I was in Llandovery [in Carmarthenshire] in October and there were a lot of acorns on four or five trees but very little on others, so it's quite localised."

"Squirrels will eat anything, they are omnivores, so I would imagine grey squirrels unfortunately will do very well this winter."

Otters

Mr Williams said mild weather would generally benefit all land animals including mice, voles, foxes and badgers especially young ones.

"Young animals and birds tend to die if there's severe frost or snow, because they are inexperienced. The more experienced animals will know."

But very high water levels can make fishing conditions difficult for water species like otters.

"Often they come out of the river and on to land, and try and cross roads, because they don't like going under bridges," he explained.

"So there are more otter deaths on the roads."