£650k 'bat bridge' in Porthmadog criticised
A bridge costing £650,000 is being built over the Porthmadog bypass in Gwynedd to help bats cross the road.
The bat bridge is designed to save the rare lesser horseshoe bats from being killed by vehicles.
Some people in Porthmadog have criticised the cost but naturalists said it was necessary to protect the species.
The Welsh Government said it had to follow EU legislation to protect the local wildlife.
Aled Griffith, 44, who has campaigned for a footbridge over the bypass for children and parents to reach a park at Tremadog, told BBC Wales: "If you think about the amount of money that's being spent on one bridge just to protect bats, I'm not against bats, but what about the children and old people and the people who want to walk along that road who used to walk there before the bypass was opened.
"They are talking about 10-12,000 vehicles running through that area every day - that's one car every four seconds.
"You try and cross that road in four seconds."
Grahame Madge, an RSPB naturalist, defended the decision to construct the bat bridge.
Mr Madge told BBC Radio Wales the lesser horseshoe bat population had declined dramatically across the UK.
"This is a species that is vulnerable to a whole range of different threats from conversion of properties to damage to their underground roosts, through to the loss of insects," he said.
"Collisions with vehicles is a major threat to bats.
"The fact that the development has gone ahead but with a provision for bats - that's the sort of thinking that we hope will help develop the economy but also help our wildlife too."
Mike Castle, a bat specialist who runs a sanctuary near Abergele, Conwy, with his wife Hilary, said lesser horseshoe bats often rely on echo location from structures like bridges to get around.
He said: "When some of our minor roads are improved, not only are they widened but the speed limit also increases.
"Because they are low flying, these bats are being hit by vehicles.. so we are encouraging them to fly higher, hence what we call the green bridges."
A spokesperson for the Welsh Government said: "The environmental bridge was part of the measures required by European/UK law to allow the building of this important bypass to proceed."
It said the population of 450 lesser horseshoe bats needed to be protected as part of the plans.