A tunnel of love built to encourage breeding between two rare hazel dormice colonies appears to have been shunned.
The aim of the walkway was to allow the colonies to mix and breed
The 25-yard tube structure, made of wire mesh and lined with leaves, was stretched over a road at Batts Combe Quarry in Cheddar, Somerset.
Environmentalists said the creatures would have a better chance of surviving and creating a larger, healthier population if they united.
But a year after construction, none appears to have made the leap of faith.
Popular with squirrels
Michael Woods, chairman of the British Mammal Society, said: "We are not overly worried. They do seem to take a long time to get round to doing things.
"We've put up nest boxes for them before and they have taken up to a year to actually start to use them, so we are hoping for a similar scenario with the tunnel.
"But if we don't find any of them using it in a few years' time we will be a bit more concerned."
He said the tunnel was put up as an experiment to discover how separate colonies could be linked over difficult obstacles such as roads in the future.
Other schemes being looked at are the extension of the hedgerow system over parts of the dormouse range which would allow the animals to move freely between colonies.
But the walkway has proved a hit with other woodland residents with squirrels seen regularly using the link as a race track.