Guano

300px|thumb|The nest of the Peruvian booby is made of almost pure guano. thumb|Human-made Bird Island (Namibia)|Guano Island near [[Walvis Bay in Namibia]] Guano (Spanish from ) is the accumulated excrement of seabirds or bats. Guano is a highly effective fertiliser due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. Guano was also, to a lesser extent, sought for the production of gunpowder and other explosive materials.

Japanese traditional cosmetic, made of the feces of the Japanese bush warbler (Horornis diphone, uguisu)