Agile frog protection

​​Why they are protected

Jersey is the only place in the British Isles where you can find this amphibian.

The agile frog population has been declining on the Island since the early 1900s.

The species has now been confined to a handful of breeding ponds in the south-west of the Island.

The agile frog is protected by the Wildlife (Jersey) Law 2021.

Wildlife (Jersey) Law ​2021 guidance

Agile frog on National Trust Jersey

Habitat, breeding and diet

Agile frogs are a European brown frog that can grow up to 90 mill​imetres​​

An adult agile frog’s diet is made up of earthworms and small insects, such as flies and beetles, and their larvae. Tadpoles feed on aquatic plants and animal matter and waste.

In Jersey, agile frogs can produce eggs any time from end of February to beginning of April. Adults start to gather at their traditional breeding site in February and March.

The number of eggs in a ball of spawn is 300 to 1,000 eggs. This is much smaller than Europe. We’re not sure why but it could be because Jersey is further north.

Frogs lay their eggs in shallow pond edges where the water is warmest. They are usually attached to twigs or plant stems.

Tadpoles take 2 to 4 months to develop into baby frogs, called froglets. It can sometimes take a whole winter. In Jersey, around 2.3% of agile frog tadpoles survive to the froglet stage. This can vary a lot between seasons and ponds.

Breeding times, sites, hatching and development periods can all vary depending on the temperature.

If they have a lot of food, new froglets can grow quickly during their first summer and can reach sexual maturity in their second year.

Threats and decline

Several factors cause their decline and breeding success:

• habitat loss
• water shortages
• loss of ponds
• predator pressure from cats, rats, birds and ferrets

The agile frog is classified in Jersey as critically endangered.

Conservation efforts

A conservation programme is in place to:

• stop the decline of agile frogs
• protect all present and potential agile frog sites
• implement head starting and reintroduction programmes to expand the population

As part of the programme, we:

• maintain the condition of breeding ponds
• improve habitats
• improve links between individual ponds
• protect spawn clumps from predators

We also collect a large amount of data during breeding season. Results help us identify progress and areas to improve.

Following our conservation efforts, the Agile frog population in Ouaisné has increased.

We work on the programme with different organisations:

• Durrell Wildlife Conservation Trust
• Societé Jersiaise
• Jersey Amphibian and Reptile Group (JARG)
• National Trust for Jersey
• Amphibian and Reptile Conversation Trust UK

How can you help

Pondwatch JE is a project run by the Jersey Biodiversity Centre (JBC). It aims to gather sightings of Jersey’s pondlife to assess their:

• level of conservation
• distribution on the Island
• habitat requirements

Everyone can be involved depending on your interest, available time and experience.

You can also record your sightings of pond wildlife.

Pondwatch JE on JBC

Jersey Amphibian and Reptile Group (JARG)​

Report your wildlife sightings

Reporting your wildlife sightings helps us understand our species, supports our research and informs decision-making.

Report your wildlife sightings​