In Spynes Mere nature reserve, a 400-ton "sandcastle" is being built to attract sand martin birds back to the reserve for the first time in 25 years. The sand structure was built by compacting sand with water and making a huge bucket-like shape supported by wooden planks that were later removed. Sand martins can safely lay eggs in the man-made nesting site. Because of droughts in Africa and a decrease in natural sandy riverbanks in the UK due to urbanization, the population of sand martins over the last few years has decreased. Project Manager Dr. James Herd says that, by building this sand structure they hope to "give more security for the population to expand."