The English toads making their homes in the treetops — and baffling researchers at Cambridge

South America is famous for its tree frogs — but it turns out that Britain ought to be just as well known for its tree toads. Annunciata Elwes reports.

The People’s Trust for Endangered Species (PTES) has carried out some new and unusual research — on toads that choose to live in trees. It all started when volunteers looking for bats and hazel dormice — part of the National Dormouse Monitoring Programme (NDMP) and the Bat Tree Habitat Key project (BTHK) — discovered common toads in nest boxes and tree cavities. ‘We couldn’t believe what we found,’ explains Nida Al-Fulaij of the PTES. ‘We’re used to discovering woodland birds and other small mammals… but we hadn’t considered finding amphibians.’

Researchers from the University of Cambridge and Froglife, supported by PTES, realising no one had ever bothered to study the tree-living nature of Bufo bufo, usually found on land and in water, decided do to it themselves. The results are extraordinary, with more than 50 records of common toads found in surveys of hazel dormice nest boxes (5ft above ground) and tree cavities usually used by bats. The highest toad was found nearly 10ft up (the surveys didn’t look higher than that).

“Researchers remain puzzled as to how difficult it is for toads to climb trees, and why they do it”

Although 50 may not seem like a large number, it is comparable to, say, blue tits, meaning common toads could be found in up to one in every 100 trees in the UK, particularly near lakes and ponds — one might even term them ‘arboreal’.

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The most popular tree appears to be the goat willow, notes the report’s first author Silviu Petrovan, but this is most likely because the species is found in wet woodland. As many of the tree cavities are small or invisible from the ground, researchers remain puzzled as to how toads find them and there is no knowledge on how difficult it is for them to climb and why they do it, although their motives could include searching for food or fleeing predators or parasites such as the toad fly, grass snakes, otters and polecats. Common toads have declined by 68% over the past 30 years across the UK, which makes the protection of natural woodland habitats ever more vital.

‘We know common toads favour woodlands as foraging and wintering habitat, but it appears their association with trees is much more complex that we thought,’ muses Dr Petrovan. ‘It also highlights the importance of collaborations and sharing data between conservation groups. Targeted research will enable scientists to better understand this behaviour and consider the impact on woodland management.’

If you see a toad up a tree, Froglife would like to hear about it — sightings can be recorded via the Dragon Finder app.