(1) [birds' droppings]: bird excrement.
(2) [guano]: A substance that exists on the coast and island where seabirds gather. It is mainly composed of partially weathered sea bird excreta. After a long time Metallogenesis , will become phosphate rock. The accumulated feces and corpses of birds, bats and seals are a kind of high-quality fertilizer. The main origin is Peru And the islands along the coast of Baja California, as well as Africa cormorant 、 pelican and Gannet Region. Bat dung is found in caves all over the world. Deep layers of seal dung are accumulated on the Islas Lobos de Tierra and Islas Lobos de Afuera islands in Peru. The quality of bat dung and seal dung fertilizer is lower than that of guano stone in Peru, which contains nitrogen 11~16%, including phosphate 8-12%, including potassium 2～3%。 
