A giant “sandcastle” has been specially built for sand martins to nest after flying in from Africa.

The 400 tonnes nesting area has been constructed by specialist sand sculptors.

They used diggers to sweep the sand into a mould made from wooden boards.

It’s hoped the 20-metres long site will bring sand martins back to Spynes Mere, near Measham in Surrey.

The birds last nested there more than 25 years ago.

Sand Martins are due to arrive during March and stay until September.

They look for sandy nesting grounds where they dig burrows and lay their eggs in a chamber.

Jamie Wardley, a sand sculptor and the director of Sand in Your Eye, said:

“We have only used sand from the site to create the structure from a giant bucket mould made from wooden boards.

“We added water to create the right mix, compacted the sand, and three to four weeks later the boards were removed.

“The new ‘des res’ is ready for sand martins to move in, leaving nature and the sand martins to do the work of sculpting hundreds of nesting burrows.”

Spynes Mere

James Herd, project manager at Surrey Wildlife Trust, said:

“Sand martin numbers have plummeted twice in the last 50 years as a result of droughts in their wintering grounds in Africa.

“In the UK, the natural nesting inland habitat along riverbanks has decreased as rivers pass through more urbanised areas and under roads, and quarrying has ceased.

“So, creating this nest bank is important to protect them against the boom and bust nature of their nesting sites and give more security for the population to expand.”

The landowner, Sibelco, helped clear the site of scrub and offered to supply extra personnel, diggers and dumper trucks for the build.

Nick Allman, the site manager, said sand martins liked to nest in active extraction sites because of their fresh vertical sand faces, but if nesting birds were found it forced work to stop.

“The sand martin bank is a way of naturally drawing them away from the active sites to where it is safer for them to nest.”