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Storm petrels are a family of seabirds that spend most of their time far from shore, soaring above the ocean. But at some point, they have to return to land to have babies.

And what better place for some of these seabirds to land than one of the driest places on Earth, in a desert?. Until recently, scientists weren’t exactly sure where in the desert some storm petrel species, like ringed, Markham’s, and white-vented storm petrels, were hiding their nests. But using their noses, they were able to literally sniff out the seabirds’ nests in the Atacama Desert.

This place is so harsh that NASA has said the environment is more similar to Mars than most of Earth. And researchers suspected these birds were nesting in the Atacama because they have been finding their mummified bodies there for decades. They believed these birds were using the harsh desert environment as protection from predators.

But despite finding their corpses, the petrels’ nests proved much harder to track down. Petrels choose to forgo a nest perched in a tree in favor of nesting in holes or rocky crevices. And the birds themselves only visit their nests under the cover of darkness.

So how do you find a petrel nest that’s underground and doesn’t have a bird hanging out in front of it? Well, you use your nose, of course! Researchers discovered that the best way to seek out a petrel nest is by smell.

The birds produce an oil to keep their bodies waterproof that has a strong, fishy odor. That scent lingers in their nests, even when the birds aren’t there. So one of the easiest ways to uncover a nest is to find bird-sized holes in the desert and then stick your nose in them to check for that tell-tale Eau de fish.

The white-vented storm petrel species has been particularly hard to sniff out because it has a milder scent compared to other species. So researchers have enlisted the help of scent-trained dogs to track down these nests. But even with the help of dogs, locating these nests can be difficult.

Because human development is dwindling their numbers. An increase in mining and renewable energy development has brought in more people, houses, and light-pollution. Light pollution, in particular, confuses these birds because it’s thought they navigate using the moon and stars.

And young birds are especially vulnerable; each year, when they make their first journey to the ocean, many get disoriented by the lights and end up dying on the desert floor. Which doesn’t help out their already threatened populations. In the end, their fishy smell might be what saves them by giving researchers a way to track down where they nest and reproduce.

Because researchers can't protect what they don't know is there. So they are smelling as much as they can to accurately document storm petrel nests and protect them from future urban developments. And what’s been found so far has shown there’s a lot left to sniff out about these incredible seabirds.

Thank you for watching this episode of SciShow! If you wanna help support the channel, you can check out Patreon.com/SciShow to learn more. [♪ OUTRO].