Mountain Chicken Frogs

A critically endangered species of frog in the Caribbean is thriving on a breeding programme in the UK. The mountain chicken frog fell under threat after its population declined by up to 90% in its native Montserrat and Dominica.

Its population was low in 2004, when an estimated 8,000 frogs remained across the two islands. Then, a fatal fungal disease, amphibian chytridiomycosis, was rampant across the region. This caused a massive population decline over a period of around 18 months.

By 2012, the species was categorised as critically endangered on Dominica, where there were fewer than 100 individual frogs remaining. It was almost extinct on Montserrat, with only two living frogs recorded.

It was time for conservationists to step in and act fast. Now, a breeding programme in the UK, led by the Durrell Wildlife Conservation Trust and the Zoological Society of London, has resulted in 76 new-born frogs to date.

What is a mountain chicken frog?

The mountain chicken frog is the common name for the giant ditch frog, or the Leptodactylus Fallax. Known for its large size, adults grow up to 22cm long. Its name, chicken frog, comes from the fact it's considered a delicacy and is said to taste like chicken.

The population was in decline initially because the frog was hunted and killed for its meat. Scientists say it is a specific species that has been eaten to the point of being under threat. Years of over-hunting, combined with a loss of habitat and Montserrat's volcanic eruptions, further reduced the wild population.

Once found on several eastern Caribbean islands, including Martinique, Guadeloupe, Saint Kitts and Nevis, as its population declined, it became restricted to Montserrat and Dominica. Earlier conservation attempts to establish a population in Jamaica and Puerto Rico failed.

In the wild, the species lives in moist habitats, such as dense forest, hillside plantations, scrub, river valleys and palm groves. It lives near streams and springs, mainly at lower altitudes.

Deadly fungus

The chytrid fungus has been described as causing the global mass destruction of amphibian life. The strain that affects amphibians was first discovered in 1999. It infects the skin and is extremely serious, as scientists say it's capable of infecting the majority of the planet's 6,000 amphibian species.

Those which are affected by chytrid fungus develop a disease called chytridiomycosis, which can be fatal – it’s linked to species extinctions and major population declines. Causing lesions in the skin of affected individuals, it prevents them from taking in oxygen, so they will eventually suffocate.

Not all species die and some have become resistant to the fungus, but others, such as the mountain chicken frog, have been dangerously affected.

The infection is transmitted by fungal spores known as “zoospores” in water and other moist environments. It spreads quickly between amphibians through direct contact, often during territorial and breeding encounters.

How is the species coping now?

Thanks to the conservation programme, the mountain chicken frog population is slowly clawing its way back from the brink of extinction. Although it's by no means safe, scientists say they are hopeful that the population will continue to steadily increase.

The conservation efforts began with the challenge of getting the frogs safely to Europe. They were transported in boxes in a temperature-controlled environment to minimise stress and protect them on the long journey from the Caribbean.

Small animals such as frogs are susceptible to temperature changes and this can prove fatal on long and hazardous journeys. A total of 50 frogs were airlifted and split into three groups, to be housed at London Zoo, Sweden's Parken Zoo and the DWCT in Jersey, in the hope the population would begin to recover.

How do they reproduce?

The UK's 12 frogs were homed in a bio-secure breeding unit at London Zoo, where they laid eggs. The female frogs make a nest into which they will lay their eggs. It is a complex reproduction system, as the female also lays unfertilised eggs and the tadpoles will feed on them.

A mountain chicken frog doesn't lay thousands of eggs, as frogs in England do. The 76 eggs laid by the females in captivity in the UK was therefore a good result. As there weren't too many of them, the survival rate was high. Adult frogs are taken to the Caribbean and released into the wild to try and repopulate the islands.

Success so far

Four groups of captive-bred frogs have been taken to Montserrat and released into the wild. They have small tracking devices inserted under their skin to monitor their progress, although these eventually run out of power.

They were released in the same territory as the two adult frogs who survived the chytrid outbreak - one male and one female - as scientists theorised that seeing as they had survived, then the new additions could too.

The hunting of the frogs has been prohibited since their population became critical. There is evidence they are now making a comeback in Dominica, and the wild population is on the increase.

Solent Plastics is proud to be associated with the chicken frog conservation project run by the Wildlife Conservation Trust and the Zoological Society of London.

We supplied the ZSL with around 100 of the large, 145-litre, clear Really Useful storage boxes to help save some of the frogs from extinction.