Guano

Guano (via Spanish, ultimately from the Quechua wanu, meaning "dung") is the feces and urine of seabirds, cave-dwelling bats, and seals. Guano manure is a highly effective fertilizer due to its high phosphorus and nitrogen content and its relative lack of odor compared to other forms of organic fertilizer such as horse manure.

Guano was an important source of nitrates for gunpowder.