Water voles 'thriving' on River Meon in Hampshire
Water voles are "thriving" on a Hampshire river six years after they were wiped out in the area.
About 450 water voles were released into the River Meon at Titchfield Haven National Nature Reserve (NNR) last year.
A further 350 are being released on Tuesday and Wednesday from private land.
South Downs National Park Authority said monitoring was ongoing.
Volunteer rangers are carrying out "latrine surveys", the authority said.
They involve putting small white rafts on to the water, which the water voles use, and then counting their droppings.
A spokeswoman said: "Early indications show the water voles appear to be thriving.
"There have been quite a few sightings by members of the public too, so it's very positive."
Before the first release in July last year, the mammal had not been recorded in the Meon Valley for five years and was considered "locally extinct", the authority said.
It added the water vole is said to be the UK's most rapidly declining mammal.
Factors, including loss of habitat, pollution and the presence of non-native American mink are thought to have been behind its disappearance.
The three-year project is also supported by the Environment Agency, Natural England, Hampshire and Isle of Wight Wildlife Trust, Portsmouth Water and Hampshire County Council.