Snails are invertebrates that are found in most parts of the world. There are many different species of snails out there, and for the most part, they are thriving. One type of snail, however, is extremely endangered, thanks in large part to a bird that was once quite rare, but today has become extremely common.

This snail is the Powelliphanta hochstetteri, and it is no ordinary snail. It is about the size of a lemon, making it one of the largest snails in the world. The brown shell protects its black body, and it slimes its way around much of New Zealand, where it is native. This snail was once so common that it could actually cause traffic problems when a large group of them was migrating across a road together.

Today, however, locals are lucky if they ever even see one, but Project Janszoon was created to try to change that. Ruth Bollongino is the science advisor and director of operations for this project. When she was talking with Justine Hausheer from The Nature Conservancy, she discussed some of the things that make this snail unique:

“These snails are quite special because they’re carnivorous. They’re not after the lettuce in your garden. They’re out hunting worms and other snails, and they can suck down earthworms like spaghetti.”

If you would like to see that happen, check out this video from BBC Earth (warning, it is kind of gross):

So, what about this bird that is forcing the snail to the brink of extinction? It is called the Weka, and it is a flightless bird that was once kept to relatively small numbers due to larger birds in New Zealand preying on them. Today, however, those larger birds are very rare, which means the Weka has become very common, which is bad news for the snail. Bollongino explains:

“What we see is that the decline of the Powelliphanta coincides exactly with the arrival of weka records up in the uplands. And we also have the shells that prove it. They are just being hammered from all sides, not to mention the effect of global warming. The older snails can deal with it to some degree, but drought can kill the young snails.”

To help combat this problem, Project Janszoon is creating weka-proof structures in Abel Tasman National Park. These large structures are 70 by 70 meters (230 by 230 feet) and keep the Weka out. This is allowing the snails (and other victims of the bird’s growth) to re-establish itself and start to work toward returning to being a common animal in the region.

So far, the team reports that the efforts have been a great success. Whether these structures will need to become a permanent addition to the park or not is still unknown. Even if the snails can return to their original numbers, the problem won’t truly go away as long as the number of Weka birds remains high.

For now, however, the efforts of this project are paying off and buying time for the snails and conservationists to figure out what comes next.

Thought that was fascinating? Here’s another story you might like: Why You’ll Never See A Great White Shark In An Aquarium