Some 100 water voles will be released in Timble Ings Woods in the Washburn Valley, part of the Nidderdale Area of Outstanding Natural Beauty (AONB) from Tuesday, following a release of the same number last September.
Yorkshire Water which is running the scheme, said surveys suggest the 100 voles brought into the site last year have become established in the woodland, with feeding signs, latrines and burrows all spotted.
Evidence of water voles has been found up to 500 metres from the original release site, suggesting they are settling into their new home, the water company said.
The aquatic mammals, immortalised as Ratty in Wind in the Willows, live along slow-flowing rivers, ditches, dykes and lakes with plenty of vegetation, making extensive burrows in the banks.
They have suffered steep declines in recent years as a result of being preyed on by invasive American mink, as well as loss and degradation of their habitat and water pollution, and have been identified as a key species for conservation in the Nidderdale Area of Outstanding Beauty.
Lee Pitcher, head of partnerships at Yorkshire Water, said: “We’re pleased to see evidence the water voles we released in September have settled into their habitat, with piles of nibbled grass and stems, as well as droppings spotted recently.
“Now they are established, we’re now moving onto the next stage – a second release in the area to further boost the population.
“We also have plans in place to extend the habitat available for the water voles later this year, with new ponds set to be created, which will allow the population to continue to expand and take advantage of the perfect habitat Timble Ings Woods provides these creatures.”
The release project forms part of a Yorkshire Water “water works for wildlife” initiative, investing £1.6 million in 15 sites across the county, to boost nature, enhance habitats and engage local communities, the company said.
Mr Pitcher said a number of sites and projects have already been identified and work is under way to invest the funding across the region.