Surrey Wildlife Trust has unveiled a giant 20-metre wide sandcastle for sand martins, tiny 12 centimetre brown and white birds, to welcome them back from Africa to nest at a Surrey nature reserve.
The huge 400 tonne sand installation will provide hundreds of new sand martin homes at the reserve for the first time in 25 years.
As one of the first spring migrants, sand martins, the smallest of Britain's swallow and martin family, visit the reserve annually on their return flight from sub saharan Africa. The nesting bank, in essence, one enormous sandcastle, has been specially designed with a 20-metre curved vertical face so sand martins can peep out of nest holes to find mates.
Sand martins begin to arrive at Spynes Mere, near Merstham, mid-March and feed there until September. The nest bank is a home for sand martins to rear their next brood of chicks. With their tiny clawed feet, the sand martins dig 50-90 centimetre long burrows into the vertical face and make a small chamber at the end, where between four and eight eggs are laid on collected vegetation and feathers.
James Herd, project manager at Surrey Wildlife Trust, said: ‘Sand martin numbers have plummeted twice in the last fifty years as a result of droughts in their wintering grounds in Africa. In the UK, the natural nesting inland habitat along river banks has decreased as rivers pass through more urbanised areas and under roads, and quarrying has ceased.’