Repairs to a major bridge in Nottinghamshire are being delayed to allow two colonies of bats to breed.
The bat colony is protected by law
The bats, which are a protected species, are nesting between concrete gaps underneath Gunthorpe bridge.
Nottinghamshire County Council has agreed to suspend the work until next spring to make sure the bats are not disturbed.
Michael Walker, of South Nottinghamshire Bat Group, says he is delighted with the decision.
"Bats are a protected species because their numbers have declined so much over the past 20-30 years," he said.
"They only have one offspring a year, so it takes a while for a colony to build up its numbers.
"We believe this is an important nursery for two species of bat - and they are just about to enter the time for breeding.
"It could be a rather large pipistrelle colony - it was only discovered late last year."
Bats and their homes are protected under wildlife laws because they are an endangered species.