The bird droppings resources of the west sand islands is abundant , particularly natural sanctuary of white bird of 鲣 in the east island , is the thousands and white stomach 鲣 bird on the tree , tree under is very thick bird droppings and the bird coprolites , the organic fatty content of bird droppings is very high , is a fatty raw material of natural 磷 西沙群岛的鸟粪资源丰富，尤其在东岛白鲣鸟自然保护区，树上是成千上万的白腹鲣鸟，树下是厚厚的鸟粪和鸟粪化石，鸟粪有机肥含量非常高，是天然磷肥的原料。
