To celebrate World Frog Day 2021 ARC’s Pool Frog Recovery Project Officer, Ben King tells us more about the northern clade pool frog and our work to conserve them.

Northern clade pool frogs are found in England and Scandinavia. Native pool frogs went extinct in England in mid 1990s, but have since been reintroduced by ARC and partners at two sites in Norfolk. The first reintroduction of pool frogs to England was established using frogs collected in Sweden between 2005 and 2008. The second, most recent reintroduction was carried out using stock from the first successfully established population.

Our native pool frogs are predominantly brown with dark brown or black blotches over the back and a lighter, often yellow, dorsal stripe. Pool frogs are around the same size as common frogs, typically up to 6cm in length, with females slightly larger than males. During the breeding season the males have a loud call which is generated by a pair of inflatable pouches (vocal sacs) each side of the mouth; a feature absent from the common frog.

Pool frogs breed much later in the year than the common frog. Breeding coincides with the onset of warm nights in May/June. The spawn ‘rafts’ are typically smaller than those of common frog, and individual eggs are brown above and yellowish below. Pool frogs are known to bask in the sunshine on even the hottest days.

ARC – and its predecessor The Herpetological Conservation Trust – has been at the forefront of pool frog conservation for many years.  We investigated the status of the pool frog and helped to determine that it was in fact a native species. We worked on the first Species Action Plan, which guided early work on the species, as well as more recent action plans and a reintroduction strategy.

In practical terms, this planning has led to the first two reintroduction projects in Norfolk, as explained above. We have been central to the actual reintroduction projects – securing the permissions and funding needed, organising habitat management, undertaking releases and follow-up monitoring. We work with government to ensure that pool frog requirements are considered in biodiversity planning and strategies. ARC now has a dedicated head-starting facility that allows us to rear the young stages of pool frogs in captivity so that can be released to reinforce the English population, when they are big enough to be less vulnerable to predators.

ARC is delighted to have been awarded significant funding through the Green Recovery Challenge Fund to deliver further conservation action for this iconic yet critically endangered animal. During this project, which runs until March 2022, ARC will consolidate the existing pool frog population through captive rearing of tadpoles, restore pool frog breeding ponds, train volunteers to survey for pool frogs, undertake specialist monitoring, bring pool frogs to a wider audience through commissioned videos and plan future pool frog reintroductions. The “Recovering the pool frog, England’s rarest amphibian” project has seen ARC employ specialist staff and will work with partners to take the next leap forward for pool frogs. 

You can learn even more about the pool frog by taking a look at our 'Species Focus: the pool frog' online training modules. Download it for free from our training page.