Durrell has helped reintroduce more than 100 tiny lizards into their natural habitat in Mauritius.
The habitat of the lesser night geckos had been destroyed over the past 400 years after invasive species were introduced to Round Island.
Goats and rabbits ate a lot of the vegetation, which exposed the tiny lizards to predators.
The 6cm geckos managed to survive on an islet called Gunner's Quoin.
But now conservationists from Durrell, alongside officials from the Mauritian Wildlife Foundation, National Parks and Conservation Service, Zoological Society of London and the University of Kent, have moved 120 of the lesser night geckos back to Round Island under their close watch.
They are currently in predator-proof enclosures to let them settle into the island, before they are set free.
Post-release monitoring has found that some have even laid eggs, which are expected to hatch in early part of this year.
Durrell’s Island Restoration Manager Nik Cole says this will reduce their risk of extinction.
"It will also help bring resilience into the entire ecosystem on Round Island, as the geckos are a valuable prey species for other animals.
We hope that this project will teach us more about how to bring other highly threatened prey species back into these unique ecosystems."