Guano refers to the excrement or droppings of birds or bats. It is often used as fertilizer because it contains nutrients that help plants grow. Full definition
Conveniently enough for the researchers, tsunami deposits in this cave are demarcated by dark layers of guano deposited between tsunamis by the cave's resident bats. (sciencemag.org)
Suddenly Lindley - Jones grabs the handrail covered in guano. (npr.org)
The wildlife down here is well fed — some of it feasting on guano and unfortunate newborn bats that lose their grip. (newscientist.com)