The beavers were brought from Germany last year
Beavers have built a dam in Devon for what is thought to be the first time in centuries.
A pair, brought over from Germany last year, have been given a two-acre enclosure at the Escot Estate in Ottery St Mary, Devon.
The pair have been hard at work on what is thought to be the first beaver dam for 400 years.
"It is a brilliant thing to watch," said John-Michael Kennaway from the Escot Estate.
"They started 10 days ago and had the basic dam up in two or three days," said Mr Kennaway, who says the pair now have a maternity lodge.
"So hopefully young beavers will emerge later this summer and a family colony will develop over the next few years."
Instinctively beavers prefer to enter their lodges from underwater and if the water is not deep enough to do so they create a dam.
"They are still building and it's getting higher by the day - it's now between 3-3.5 ft tall."
They started building the dam ten days ago
In the UK, there are believed to be only 15 pairs in existence. The native population was hunted to extinction over 400 years ago.
The few other beaver colonies introduced in England in recent years are on lakes and do not build dams, said Mr Kennaway.
If the project at Escot is successful, it will be a significant step forward in the reintroduction of beavers to Britain.
Small groups are being allowed to evening sessions to observe the nocturnal creatures - one of the world's largest rodents.