guano

The cave was filled with guano.

Guano is often used as a fertilizer.

The guano from bats is high in nitrogen.

The island is known for its abundant guano deposits.

Guano mining can have negative environmental impacts.

The guano harvest season is in full swing.

Some caves are protected to preserve guano deposits.

Guano can be a rich source of nutrients for plants.

The smell of guano filled the air near the nesting site.

Scientists study guano to learn about the diet of certain animals.

You can smell the guano or the bird poo in the air.

It's very pungent. You can smell the guano or the bird poo in the air.

These worked just as well, if not better, than guano.

But guano might not have outlived its usefulness just yet.

In the caves, there's a scraping of guano off the floor. That's bat feces.

A clue to the source of the guano can be heard above the noise of the river.

The scientists found guano which is sometimes used as fertilizer to be crucial to the functioning of tropical ecosystems.

The cave floor is covered in guano, so plentiful that 10 minutes' work can fill these farmer's baskets.

Almost immediately, the Peruvian government started huge mining operations, selling the guano to any country that wanted it.

It was nicknamed the 'billion dollar bird, ' because its poop, or guano, was an amazing fertilizer.