Helping save the nation’s rarest toad with a sweet music

In the latest effort to boost their numbers, a small herd of cows has been introduced to the sand dunes at the RSPB’s Mersehead Nature Reserve in Dumfries and Galloway.

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One of the UK’s few places where the tiny toads survive, the cows have been brought in to act as four-legged lawn mowers – helping to improve the quality of the toads’ favoured freshwater pond habitats by getting rid of pesky scrub and brambles that can choke and clog them.

At the same time, the cows’ dung is helping to fertilise the ground, attracting birds to feed and spreading seeds which it’s hoped will eventually create new habitats for the mysterious little toads.

The rare natterjack toad is proving harder to find (Image: Newsquest)  

Rather than attempting to erect fences to prevent them straying into highly sensitive areas, nature reserve managers are allowing the cows to roam relatively freely, and instead have fitted them with high-tech collars which play a gentle tune to warn them to stay within certain boundaries.

Should they wander too near areas where they are not supposed to roam – such as the reserve’s beach - the collars emit a serious of alarms and warnings. If those are not effective, the collars deliver a mild electric shock, said to be significantly less than if the cows strayed too close to a typical farm electrified fence.

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The cows’ movements are monitored remotely by reserve staff using an app, who can create “invisible fences” at key points to ensure they neither over nor under graze in certain areas.

Although found in a wide range of locations in Europe, natterjack toad numbers across the UK are thought to have slumped by around 75% since the early 1900s, mainly due to the loss of their sand dune habitats.

It is feared there are just 2,500 breeding females left at a handful of locations.

However, establishing precisely how many toads might be in any single area has usually been ‘hit or miss’, involving researchers heading out under cover of darkness in the specific climate conditions favoured by the species in order to count each one.

While finding their location could also be tricky: the little toads, with their unusually short legs that mean they tend to run rather than hop, often move around, seeking out new freshwater ponds free from predators.

To help count their numbers more accurately, the teams turned to photographing their distinctive markings and, working with natterjack expert Dr Pete Minting, fed the images into a computer programme originally developed to help identify sand sharks and manta rays from their patterns.

It gave each toad a code number – including one particular toad which appeared every year of the three year survey. Because of the distinctive ‘D’ shape on its back, it was dubbed ‘Dave’.

The surveys showed instead of just 50 toads, there were closer to 150 – and possibly more which had not been spotted - raising hopes that the natterjack in the area may be in a better position than had been feared.

Rowena Flavelle, RSPB Scotland warden at Mersehead, said the introduction of the cows is the latest effort in two decades of work aimed at boosting numbers of the toads in the area.

“Natterjack toads are relatively common in Europe but the Solway Firth is edge of their range.

“We carried out a translocation project in 1999, bringing spawn strings from Southerness to Mersehead, which was found to be successful.

“But storm surges in 2014 destroyed sand dunes system along the west side of the nature reserve and the stretch where their pools are.

“The assumption was that the sand dunes were washed away and the toads washed away with them. “

She added that the nature charity is working with a local farmer, whose cows were introduced to the site in July.

“Cattle have been introduced as a trial so we can see how well the collars work – we don’t want the cows on beach and are waiting to see how they will affect the habitat.

“The cows have collars that tell them where the ‘invisible’ fences are, there are no welfare issues - it’s no difference from a standard fence. 

“They hear music as they approach the boundary, they learn to turn back and go away from the fence or they get a very small shock which is less than they would receive from a conventional fence.

“The hope is that they are breaking it up and will eventually make a mosaic of habitats which will improve the habitat for natterjack toads to move alone the coast.”

Natterjacks have a distinct yellow line down their back and green eyes compared to the typical bronze colour of other toads.

 They live among the nature reserve’s ten-foot high sand dunes, where they feed on beetles, sandhoppers and other invertebrates but face a series of challenges due to the loss of their sand dune habitats and climate change.

They are also at risk during winter when they hibernate by digging into the Solway sand dunes, when high tides can wash away their burrows.

The toads, which can live for up to 15 years, also need regular new sources of freshwater ponds, as established pools can become havens for predators such as fish and dragonfly larvae which feed on natterjack spawn and tadpoles.

While a shift from traditional sheep farming on the Solway saltmarshes – or merse -  meant scrub plants like hawthorn and buckthorn have thrived, making it tricky for new freshwater ponds favoured by the toads to form behind the sand dunes.

It’s hoped that the toads will eventually establish populations in sand dunes running right along the coast, from the Mersehead reserve to Southerness, with the cows playing a role in helping to improve their habitat.

 “It’s a slow process,” she added. “The first stop is getting the habitat right and then hopefully they will move themselves. But it is looking good for them.”