guano

Their guano, or dung, can also be used as fertilizer.

The seabirds' droppings, known as guano, carry nitrogen and phosphorus, important nutrients that leach into the surrounding seas fertilising surrounding coral reef environments.

And so sprang up a gigantic industry dedicated to the harvesting of guano from Latin American bird colonies, where there were huge piles of the stuff.

Researchers have discovered a new avenue by which viruses may spread from bats to other mammals: in bat guano eaten by chimpanzees and other animals.

According to the peer-reviewed study, which features in the Nature journal, guano is an "alternative source of crucial minerals" for the animals after the the palm trees they once consumed were "harvested to extinction".