Rare mice, relocated to the Scottish mainland while a mass cull of rats took place on a small island, have been returned to their home.
About 40 mice have been returned to the island
About 150 wood mice were taken from Canna in the Inner Hebrides to Edinburgh Zoo and Highland Wildlife Park last year.
They were removed so that international pest controllers could eradicate the island's 10,000 non-native brown rats.
The rats had threatened the mice and seabird population.
The £500,000 cull was launched by the National Trust for Scotland (NTS), which owns the island.
It ended in January and routine monitoring in April found no sign of rats.
The Royal Zoological Society of Scotland (RZSS), which owns Edinburgh Zoo, said about 40 mice had now been returned to the island and would be monitored for two years.
The remainder would be reintroduced in phases.
David Windmill, RZSS chief executive, said: "We are pleased to have been involved with this project and hope to have valuable nesting seabirds on the island, as well as conserving a rare and unique Scottish mouse."
Abbie Patterson, national species recovery officer at NTS, said: "We are delighted that the RZSS were able to help us with this phase of the project and we look forward to the population of seabirds thriving once again on the cliffs of Canna."
New Zealand pest controllers were hired in October 2005 to cull the marauding rats, which had been feasting on the eggs of seabirds and posing a threat to the mice.
The rats were killed using poisoned baits.