RNAS Culdrose helicopter flies red squirrels to Tresco
Twenty red squirrels have been flown over to Tresco on the Isles of Scilly to boost a breeding experiment.
Five of the rare endangered native mammals were introduced last year, but only two survived.
The new colony of squirrels from the British Wildlife Centre in Surrey, was flown over by a helicopter from RNAS Culdrose in Cornwall.
Mike Nelhams of Tresco Abbey Gardens said the colony could start breeding as early as next year.
"Tresco is an ideal place for these very cute little animals," he told BBC News.
"We have a lovely woodland for them, there are no natural predators and with no grey squirrels, they are safe from squirrel pox."
The native red squirrel population has been decimated by squirrel pox [parapoxvirus], which is carried by the grey squirrels that were introduced in the UK in the late 19th Century.
Grey squirrels have built up a natural immunity to the virus, but it is fatal to red squirrels, which are now extinct in many parts of Great Britain.
According to the Forestry Commission there are about 140,000 red squirrels left in the wild, compared with more than two million greys.
Mr Nelhams said the idea of introducing red squirrels, mooted by Daily Telegraph wildlife columnist Robin Page, has been supported by Prince Charles and Tresco's owner Robert Dorrien-Smith.
The Prince of Wales is the patron of the Red Squirrel Survival Trust (RSST).
The new arrivals "hitched a ride" on a Royal Navy search-and-rescue helicopter during a routine training exercise.
"We have the heliport here and as it's not unknown for the Culdrose helicopters to touch down here. We held off getting the squirrels until it coincided with a training exercise to test equipment," Mr Nelhams said.
The red squirrels will be released from their cages on Friday and will be free to roam the Abbey woodland.
However, Mr Nelhams said food and water would be provided for them every day until they could forage sufficiently for themselves and no longer needed to be fed.
"The ones we have are quite sociable little creatures and make their way back most days for hazelnuts, fruit and vegetables," he said.
"In terms of their natural diet, red squirrels love pine cones and the magnificent Monterey pines we have here on Tresco means there's a huge supply of cones."
The squirrels - believed to be an even mix of males and females - are about a year old and could begin breeding in the spring.
Litters vary between one and six, but the average is three.
Mr Nelham said it was "highly unlikely" Tresco would become overrun by red squirrels.
"It's very early days, but if the numbers really grow we could probably catch some - they're quite easy to catch - and relocate them - perhaps even to Cornwall."
The Cornwall Red Squirrel Project is currently culling grey squirrels ahead of plans to reintroduce red squirrels in two parts of the county - the Lizard and West Penwith.