Hundreds of bats are raising their young inside a church tower despite a team of builders working just a few feet away.
A nursery has been set up by the bats to raise their young
Vital repair work on St Cadoc's Church in Llangattock Lingoed, near Abergavenny, had been estimated to take just a few months.
But unexpected problems meant that the work, which began in 2002 after the bats had left for the winter, is still going on.
Officials at the church were concerned that the presence of the builders would deter the bats from returning, but the creatures have ignored the workers and are happily bringing up their young.
The Reverend Jean Prosser, parish deacon said: "There are hundreds of bats there and they don't seem to mind the builders one bit.
"We had kept aside the tower for them and this year, the same as always, they are using it as a nursery to bring up their babies."
The bat colony which roosts in the church, dating back to the early 1200s, includes a quantity of lesser horseshoe bats, an endangered species rarely seen in the British Isles
The roof had to be completely removed during the repairs
Like other bat species, they leave their summer roost to find caves, mines or cellars where they can hibernate through the winter months before re-appearing in the spring.
When the building work first begun, it was hoped that it would be completed before the bats came back after their winter away.
"The building work has taken a lot longer than we first thought it would because we found there were other things need to be done," said Dr Prosser.
"It has taken about 14 months in all.
"But finally we have had the roof put back on and the scaffolding has been taken away.
"All being well it should be completed by September," she said.
Dr Prosser said that to mark the end of the building work, an open weekend will be held at the church from the 12 to 14 September.
And the bats could have a starring role in the event.
"The bats make a lot of noise but you need to have special equipment to hear it, so we are hoping that we can get a bat group to come with their microphones so we can hear them," she said.