DOG-WALKERS enjoying a stroll around a York common have been put on alert against some slithery customers.

Venomous adders – which can inflict a nasty bite if they feel they are under threat – have been spotted in the Strensall area as the summer warmth drives them out of the undergrowth.

Now an organisation which protects the city’s wildlife is asking for anybody who comes face-to-face with the snakes to get in touch with them as they aim to compile a picture of where the creatures are calling home. The first sign of the lurking adders came at the weekend when Christine Green, who lives near the common, was exercising her daughter’s two dogs on part of the patch of open land.

“We were on part of the common known as the bivouac area, quite near the car park, when my partner suddenly said ‘Stop – there’s a snake!’” said Christine, 52.

“It was only about two metres away from us and just sunning itself on the footpath, and we both just froze and took a close look at it – I could tell it was an adder because of its colour and the diamond shapes on its skin.

“The snake was probably between 18 inches and two feet long and I was really surprised to see it there. I’ve never seen something like this on the common before.

“I just wanted to warn people that there may be creatures like this and to be careful, because they are venomous and they’re obviously coming out into the open at this time of year. But it’s also nice to see that wildlife such as this is still around and has not been killed off.”

Adders are the UK’s only venomous snake, but they are regarded as placid and only likely to bite if they feel threatened or if people try to catch or handle them.

“However, their venom can be lethal to pets.

A spokeswoman for Yorkshire Wildlife Trust said: “Our lowland adder project has been working hard to develop prime adder habitats on selected heath sites.

“Both the habitat and the unique species of snake are extremely threatened and this project will help restore vital habitats, which are also essential for many other species of plant and animal.

“Strensall Common forms part of an internationally important lowland heath.”

Anybody who sees adders in their neighbourhood should email lowland adder conservation officer Claire Jackson at claire.jackson@ywt.org.uk