9 March 2012 Last updated at 07:08

Saving frogs in a shipping container

By Ella Davies & Victoria Gill Reporters, BBC Nature

Keeper Ben Baker cares for the frogs' daily needs and future survival

Critically endangered green-eyed frogs from Costa Rica have taken up residence in an unusual home in the Cheshire countryside.

Conservationists at Chester Zoo have converted shipping containers to mimic the amphibians' rainforest homes.

The frogs were thought extinct until a single breeding pond was discovered in 2005.

Experts are hoping to breed a "safety net" population that can be transferred back to their natural environment.

The lead keeper of herpetology at the zoo, Ben Baker, has followed the frogs' journey from start to finish.

After researchers from Manchester Museum discovered the vulnerable population, spawn was sent to the zoo to preserve future hopes for the species.

Little data is available on the species but their dramatic decline is linked to the Chytridiomycosis fungus that is affecting amphibians worldwide.

Costa Rica in a container

"They're maintained in a bio-secure unit that we call an amphibian pod," Mr Baker tells BBC Nature.

The pods are converted shipping containers, chosen for their easy availability, but some modifications have been made to help the frogs feel at home.

"Large metal boxes aren't very good for holding a stable temperature so there's an awful lot of insulation," says Mr Baker.

Alongside the industrious air-conditioning and water treatment are some more DIY solutions.

"The bio-tents that we've created are about two square metres of cloud forest kept within a tent and a paddling pool.

"They're mesh enclosures made out of mosquito netting which allows free air movement - which is really key to this species thriving," Mr Baker says.

The frogs get their name from their green-rimmed eyes

The self confessed "frog fanatic" says that caring for the frogs in captivity has been a considerable challenge.

"It's a member of a group called Ranid frogs - they're very common, like the frogs you get in your garden.

"We expected them to be as easy and as straightforward to breed but it turned out to be a much harder thing to do.

"Two or three seasons have passed now where we've tried different techniques to get them to spawn."

Staff at the zoo are hopeful that this will be the frogs' year and Mr Baker says that the ultimate goal is for the team in Costa Rica to rear a population in their own shipping container and eventually reintroduce the species.