A group that helped more than 1,000 toads reach their breeding ground safely say they fear the creatures have died after a reservoir was drained.

Members of Wrexham Toad Patrols ensure the amphibians cross a busy road to reach the Nant-y-Ffrith reservoir each year.

However, it was emptied by the Hafren Dyfrdwy water company, which said it was carrying out essential safety improvements.

Toad patrollers said they were shocked after learning that this had happened over the Easter weekend, saying the toads had been due to leave the site in a few weeks at the end of the breeding season.

“The males are very vocal so you can usually hear them. It was silent,” said volunteer Becky Wiseman.

“We got as close to the reservoir as we could but we saw no life.”

Conservation charity Froglife led research last year which found common toad populations in the UK had declined by 41% in the last 40 years.

It said much of the reduction was due to the lack of garden ponds – making sites like reservoirs even more important.

Becky added: “I appreciate that people see humans as the priority but we’re not the only ones here and I think we need to work together to prevent damage going forward.”

Volunteers at two sites in Wrexham – Ruthin Road and Brymbo – regularly give up their evenings between February and May to help gather and move toads, frogs and newts.

“There’s a whole ecosystem,” said another volunteer Ella Thisleton.

“We don’t know what next year will bring from this, so we’re all very upset.

“If we’d known about it there could have been things that we could have put in place to try and prevent any fatalities.”

Every year during the breeding season, the volunteers work to help toads cross the busy A525 from their land habitat to their ancestral breeding ground at the reservoir.

They said they had assisted almost 1,500 this year, four times as many as last year due to an increase in volunteers.

The group’s Teri Davies said: “All of us are totally gutted, all that hard work and it’s just gone.”

She said if work had been delayed the deaths could have been avoided, adding: “If it had just waited four to six weeks then they would have laid their spawn, the spawn would have turned to toadlets.

“They would have left the water free for the maintenance works.”

A Hafren Dyfrdwy spokesperson said it understood how “concerning this situation is for the local community”, adding: “The work at Nant-y-Ffrith is essential to ensure this critical operational reservoir remains safe now and for the future, and continues to meet strict safety requirements.”

In addition, the company was “currently reviewing what has occurred alongside our ecologists on site”.

Birds, including curlews and geese also use the reservoir and there are fears that their habitat has also been disturbed.

Hafren Dyfrdwy is planning to work with the group to discuss the next steps while the construction work continues.

The spokesperson said it wanted to “identify ways to put things right for the future”, adding: “While the reservoir plays a vital role in supplying drinking water, we recognise it is also an important space for local wildlife and the community.”