16 October 2023

A global coalition of conservationists are calling for urgent action to save the Critically Endangered mountain chicken frog, after a new survey found only 21 of the giant frogs alive in the wild.

Once found widespread across seven Caribbean islands including Montserrat and Dominica, the recent survey of hotspots on Dominica – now the last place on Earth where the species can be found in the wild -  found the worryingly low number, with conservationists hoping the shocking figure will shine a light on how threats such as infectious disease, habitat loss, invasive species, climate change and pollution continue to threaten the future of this culturally significant frog.  

Dominican ecologist Jeanelle Brisbane, speaking on behalf of the Mountain Chicken Recovery Programme (MCRP), said: “The charismatic male calls of the mountain chicken frog once reverberated around the rainforests of Dominica at night - we want to bring this sound back to our island, for our people. It’s devastating that future generations may never hear this iconic soundscape which defines our island.”  

Since 2002 the MCRP – a global collaboration between scientists, conservationists and the governments of both Monserrat and Dominica - have conducted significant research into the Critically Endangered frog as well as developing innovative management techniques to try and prevent its extinction.   

Mountain chicken frog close up
Waterfall in forest in Dominica

The most recent survey saw 28 conservationists from 11 organisations, including ZSL, spend a total of 960 hours over 26 nights searching for the frog – one of the largest in the world.

Why are mountain chicken frogs Critically Endangered?

Despite surviving hurricanes, volcanic eruptions and being hunted for centuries, the mountain chicken frog has been driven to the brink of extinction by a deadly microscopic fungus. Amphibian chytridiomycosis arrived in Dominica in 2002 and caused the population to plummet by over 99 per cent. This disease has caused drastic declines in around 500 frog species across the world and led to over 90 extinctions in just 50 years.

But the recent survey also revealed how, in addition to facing disease, the presence of invasive species such as cats, dogs and rats, the loss of suitable habitat due to agriculture, quarrying and construction, and deaths due to roadkill all add to the challenge of protecting this species - two of the total 23 frogs counted were found dead on the road.

Jeanelle added that while previous population monitoring efforts suggested 50 mountain chicken frogs were left on the Caribbean Island the new survey confirmed this number has fallen further. She added that climate change was also a factor in the terrestrial frog's decline: “Sadly, we’re finding the frogs closer and closer to busy roads as they search for water, due to our rivers being so dry due to the changing climate in Dominica.” 

Two conservationists undertaking survey at night
Mountain chicken frog sitting on forest floor

Weighing almost 1kg - as much as a bag of sugar - the mountain chicken frog is the largest native frog species in the Caribbean. Its reddish brown and cream colour provides effective camouflage against the leaf litter of the forest floor, while its large, drumstick legs hold enough power to jump high enough to clear a standing adult human.  

Hope for a species on the edge of extinction

Professor Andrew Cunningham, Professor of Wildlife Epidemiology at ZSL’s Institute of Zoology and leader of the international team that identified chytridiomycosis as a global threat to amphibians, said that despite the challenges it’s facing, there is hope for the species. “In two years, these vitally important apex predators could become Extinct in the Wild, meaning they will cease to exist anywhere except in human care.  

“It’s been over 20 years since amphibian chytridiomycosis first arrived in the Caribbean, and in that time mountain chicken frog numbers have been decimated. However, this year’s survey did give us one reason for optimism. Despite all the threats these frogs are facing, the team identified one particularly special frog. He was tagged as a mature individual in a survey eight years ago, so we know that this frog is at least 11 years old - making him the oldest wild mountain chicken frog known to be in existence.”

“If this individual can persist in the face of endless challenges, it gives us hope for the future of the species more widely – and we need those with the power to rewrite this story to invest in that future.”

During the survey, the ZSL team also took mouth swabs from the resident frogs to determine their genetic make-up while also testing them for the fungus. Professor Cunningham said the team aimed to find out if these last remaining frogs had any evidence of developing resistance to the deadly chytrid fungus – a potential game changer for the species.  

Mountain chicken undergoing health check
© Chester Zoo
Conservationists undertaking survey at night

“If these frogs have developed resistance to chytrid fungus this could also give us immense hope for the species. The next step will be to bring these resistant genes into the breeding programme population so that we can a strong and genetically diverse population that can one day be returned to the wild in Montserrat and Dominica.” 

Andrés Valenzuela Sánchez, Research Fellow in Wildlife Health at ZSL’s Institute of Zoology added that the team were working to understand how to recover mountain chicken frog populations after disease drove such startling declines. “We’re working to understand how to recover mountain chicken frog populations - but our recent work shows that the chytrid fungus is not the only threat we must tackle to avoid these frogs being wiped out forever, and we need urgent support to save the species.”

The survey was part of the cutting-edge Mountain Chicken Recovery Programme – an international collaboration bringing together expertise from across the Caribbean and Europe - to create a future for this species. The mission to save the mountain chicken frog includes caring for safety net breeding populations – including one at ZSL’s conservation zoo, London Zoo - and ground-breaking developments to treat the disease, which ZSL has been at the forefront of for more than 20 years.

The Mountain Chicken Recovery Programme is made possible through the joint partnership of ZSL, Durrell Wildlife Conservation Trust, WildDominique, Nordens Ark, Chester Zoo, Riga Zoo, Fauna and Flora, re:wild, The Government of Montserrat’s Department of Environment and The Forestry, Wildlife and Parks Division of the Government of the Commonwealth of Dominica.  


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