Numbers of water voles has declined sharply in the UK in recent years
One of the country's most endangered mammals is living on the banks of the River Tees.
Water voles are breeding in the grounds of the RSPB centre at Saltholme.
A watching station has now been set up to try and catch a glimpse of the animal.
Numbers of water voles have fallen sharply over the last 20 years and there are fears that it could become extinct by 2016 if the decline continues.
However there are signs that the population has stabilised in parts of the North East in recent years.
One of the reasons for the water voles' decline is a loss of habitat and fragmentation, the creatures like to live near slow flowing rivers with lots of vegetation.
Interloper the American mink is a threat to British voles
When forced from these areas they can become isolated and at risk from predators like the American mink.
Toby Collett, an assistant warden at RSPB Saltholme, says by creating a good environment for birds they have also encouraged mammals like voles, hares and insects to live at Saltholme as well:
"Voles are quite susceptible to water pollution and changes," says Toby, "we're here trying to get the right conditions for them.
"People think birds and voles don't really mix, but if you conserve the habitat for birds you conserve it for everything.
"We do dragonfly walks, we've got a lot of butterflies and wildflowers.
"Our hare numbers have rocketed, they breed just outside of a compound we work at."
Voles like apples
A watching station has been set up at in the area vole tracks were found.
Toby says they are using fruit to entice the animals - but it hasn't gone exactly to plan so far:
"We know where the voles are, we've seen the tracks and we put a camera down there.
"We've got some apples there because they like apples," says Toby.
"The camera is trigger sensitive. I went down the other day and there were about fifteen shots.
"I thought 'brilliant, it must be a water vole because they love apples!'
"But the first was me walking off. Then the next shot was a little foxes snout, shuffling in and snuffling back out again.
"Then the next fourteen shots were just the fox, destroying all my hard work on the water vole feeding station and eating all the apples!"
Toby says they aren't sure how many voles are on the site.
Water voles burrow into river banks
He hopes habitat work done on the site will encourage them to spread and says it has already brought results with another animal.
"We've dug a lot of our ditches out to get the water flowing a bit more freely and to get a bit more space for the animals to move along," he says.
"Its also good for fish and for another thing... We found an otter print the other day so we have otters in the area as well."
And Toby says the work carried out on the site should give the voles some protection from air raids.
"We have a large reed bed area."
"It makes it a bit harder to see them there but it is very safe for them, they can hide away form any arial predators."