Toads found up trees and in nestboxes by shocked University of Cambridge and Froglife researchers

Volunteers surveying hazel dormice and bats in trees were shocked to find more than 50 common toads in nest boxes and tree cavities at least 1.5 metres up.

It had been thought they were terrestrial animals - but one was found three metres up a tree, and it is thought some could be venturing higher still.

The study represents the first time that the tree-climbing potential of amphibians has been investigated at a national scale.

“We couldn’t believe what we found,” said Nida Al-Fulaij, conservation research manager at the wildlife charity People’s Trust for Endangered Species (PTES) “We’re used to discovering woodland birds and other small mammals in nest boxes but we hadn’t considered finding amphibians in them.”

PTES was supporting research led by the University of Cambridge and Froglife, which has been published in the journal PLOS ONE.

First author Dr Silviu Petrovan, a senior researcher at the University of Cambridge and trustee at Froglife, said: “This is a really exciting finding, and significant for our understanding of the ecology and conservation of common toads - one of the most widespread and abundant European amphibians.

“We know common toads favour woodlands as foraging and wintering habitat, but it appears their association with trees is much more complex than we had previously thought.”

It is not known why they climb trees or use nest boxes, but they could be searching for food, avoiding predators or evading parasites such as toad fly.

Common toads spend their time on land and in water during breeding and there have only been a handful of documented sightings of them in trees in the UK.

Unlike in bat and dormouse surveys, trees have not been surveyed for UK amphibians before.

The study demonstrates the importance of sharing data between conservation organisations representing different species - and underlines that we still have much to learn about even well-known species.

Many of the cavities typically used by bats were small or not visible from the ground. It is not clear how the toads are finding them or how difficult climbing particular trees is for them.

They were not found in boxes or tree holes with other species, but were seen using old nests made by dormice and even birds.

Extrapolating the data, it is thought common toads could be found in up to one in every 100 trees in the UK in particularly favourable areas, such as near large ponds or lakes.

The study also demonstrates the ecological importance of tree cavities and of protecting our natural woodland habitats - especially ancient trees.

In 2016, Froglife research showed that common toads have declined by 68 per cent over 30 years in the UK.

“Future targeted research will enable scientists to better understand the reasons for this tree-climbing behaviour in toads, and how woodland management should take it into account,” said Dr Petrovan.

Froglife urged members of the public to record any sightings they have of amphibians in trees on their Dragon Finder App, or to contact them directly.