Guano

Guano is the excrement of bats and birds. This excrement is exceptionally high in nitrogen, phosphate, and potassium, three nutrients which are essential for plant growth. Therefore, it is often used as fertilizer, to make plants grow more quickly.

Guano Media

Man-made Guano Island near Walvis Bay in Namibia
The guanay cormorant has historically been the most important producer of guano.
Insectivorous bats, such as this Mexican free-tailed bat, have historically been the most important producers of bat guano.
Insectivorous bat excrement is primarily made up of insect bits and pieces.
Bat guano under a microscope reveals tiny particles of insect exoskeletons, which are mostly chitin.
Chincha Islands where guano was found in abundance. Mining was done on site and ships transported it to Europe.
Advertisement for guano, 1884
Aerial view of Guano Point. Old tramway headhouse is at the end of dirt road (right). Second tramway tower is more clearly visible, on skyline to right. Bat Cave mine is 760 m (2,500 ft) below, across the canyon.
Workers load guano onto a cart in 1865