Thank Goodness for Guano

“Guano” is basically just a fancy word for the white stuff excreted by birds that makes a mess on your car, or worse yet, your head. But lately I have been thinking about guano with a whole new appreciation for the stuff.

Why, you ask?

Because an obscure law passed in 1856–that remains on the books to this day–allowed Americans to “claim” as U.S. territories uninhabited islands that are covered in guano. Guano makes great fertilizer and it was in huge demand back then. Many remote islands were drenched in bird poop from thousands of years of bird bathroom breaks during long migrations–and they were ours for the taking. And take them we did!

Workers in 1964 collect guano from one of the Chincha Islands of Peru where sea birds nest. (Photo by Bates Littlehales)

Over time, the U.S. claimed more than 100 islands this way, including seven tiny atolls in the middle of nowhere in the Pacific Ocean. Over the years one or two were used for government purposes–Wake Island, for example, is the site of a famous battle during WWII. But mostly they went unnoticed and undisturbed.

These seven remote islands are back in the news now for another reason.

On June 17, President Obama announced his intention to greatly expand the Pacific Remote Islands Marine National Monument originally declared by President George W. Bush. President Bush protected up to 50 miles from the shore of each island. Now President Obama has proposed to protect out even further–possibly up to 200 miles from each atoll. That would increase the ocean area being protected from 216,000 to more than 2 million square kilometers. If it weren’t for all that bird poop, we could never have claimed these islands as U.S. territory, and the oceans around them might never receive the protection now being contemplated by the President.

An aerial trolley transports guano from one of the Ballesta Islands in Peru in this vintage photo from the 1920s. (Photo by Robert E. Coker)
An aerial trolley transports guano from one of the Ballesta Islands in Peru in this vintage photo from the 1920s. (Photo by Robert E. Coker)

Guano mining is no longer a threat to these pristine atolls, but deepsea hard-rock mining is. These atolls are surrounded by hundreds of undersea mountains that are home to marine species unique only to them–many yet to be discovered. Undersea mountains in the equatorial Pacific are also rich in valuable manganese nodules from which minerals like nickel can be derived.

People used to think that deepsea mining was decades away, but the international tribunal that controls open ocean mining recently issued seven permits to companies itching to begin prospecting in the deep Pacific.

Currently, there are permits covering more than 1.2 million square kilometers of ocean–an area larger than all the current marine protected areas combined. Ironically, and thankfully, the antiquated law that was enacted to encourage guano mining may actually save a large swath of the Pacific from this new mining threat.

Changing Planet


Monica Medina is the Senior Director for International Ocean Policy at the National Geographic Society. She is determined to help save endangered wildlife and the last wild places in the ocean.