What is the chemical content of guano?

Bird guano is the accumulated excrement and remains of birds such as cormorants, pelicans, and gannets.

Guano is 11 to 16 percent nitrogen, 8 to 12 percent phosphoric acid, and 2 to 3 percent potash.

The excellent fertilizer is harvested from islands off Peru, Baja California, and Africa.

Bat and seal guano is also highly prized.