A grant of nearly £2.5m is to help enlist hundreds of volunteers to ensure the long-term survival of key Scottish red squirrel populations.
The Scottish Wildlife Trust (SWT) has been awarded the funds from the Heritage Lottery Fund (HLF).
Sites in and around Aberdeen, in the central Lowlands and in southern Scotland will be targeted.
The project aims to provide training to hundreds of people and land managers to help protect the squirrels.
The Saving Scotland's Red Squirrels (SSRS) developing community action project will run over the next five years in the three key areas.
Scotland is home to under 120,000 red squirrels, three quarters of the UK population.
The main threat to native squirrels is said to come from competition with grey squirrels and the spread of the deadly squirrelpox virus.
SSRS Project Manager Dr Mel Tonkin said: "Our work since 2009 shows that through targeted control of grey squirrels it is possible to reverse the decline of our native reds and help them to return to former territories.
"Red squirrels are one of Scotland's most-loved species.
"Thanks to National Lottery players we will be able to empower communities to help protect not just their local red squirrels, but major populations of the species in Scotland, and ensure that future generations can continue to see these special animals."
Environment secretary Roseanna Cunningham said the investment was "very welcome" to help a priority species.
"SSRS has led important work to conserve them since 2009 so it is fantastic that players of the National Lottery will help to mobilise communities to take practical action to protect one of our best-loved animals," she said.
Lucy Casot, head of the HLF in Scotland, said: "Many of us have a soft spot for red squirrels and sighting one in the flesh is an exciting, but sadly increasingly rare experience.
"Thanks to National Lottery players' support, we're helping organisations and communities protect and care for Scotland's red squirrels, which represent three-quarters of the UK's dwindling population."
She said they had been impressed by the SWT's "collaborative approach" to saving the species.
The work in the three key areas includes:
- continuing efforts in Aberdeen City and Aberdeenshire towards making the area a grey-squirrel free zone by developing a rapid response system to "detect and remove" any remaining greys
- in the central Lowlands, stopping the northern spread of greys beyond the "Highland Line" - home to the UK's largest population of red squirrels unaffected by greys
- focusing on eight key conservation areas in southern Scotland to help stop greys ousting reds
The project also hopes to create "widespread understanding and appreciation" of the current risks to red squirrels and demonstrate the methods used to successfully protect them.