Guano (Spanish from Quechua: wanu) is the accumulated excrement of seabirds or bats. As a manure, guano is a highly effective fertilizer 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. The 19th-century seabird guano trade played a pivotal role in the development of modern input-intensive farming. The demand for guano spurred the human colonization of remote bird islands in many parts of the world.