A project in Hawaii aimed at bringing back habitat for seabirds has, at the same time, restored coastal dune habitat. It’s an effort that’s taken nearly three decades, but it’s paying off in a big way.

The birds are wedge-tailed shearwaters, grey and white with a 3-foot wingspan. As this article on the restoration project from the Nature Conservancy Magazine describes, the birds migrate thousands of miles each year but generally return each spring to the place where they hatched, nesting in underground burrows. They were once abundant on the island of Molokai, where the project is taking place, but after Western settlers arrived (bringing cats along with them), the birds began to disappear.

It’s not just the cats that caused the population decline; the birds have had difficulties from many non-native species—both plants and animals—that now thrive on the island. The story is a familiar one, with a few variations. A species of mesquite tree known as kiawe has taken over large areas of Molokai. Kiawe was brought to Hawaii in the early 1800s and cultivated because its seeds provided cattle feed. The trees grow so densely that thickets of them are pretty much impassable, and they’ve crowded out the native grasses and shrubs that form much of the shearwaters’ nesting area. In addition, the thickets provide great hiding places for growing populations of feral cats.

Around the same time that the trees were being imported, farmers growing sugar cane in Hawaii were having problems with rats, so they brought in animals to hunt the rats: mongooses. It seemed like a good idea, but as the article notes, “Rats are nocturnal, so the diurnal mongooses instead hunt other species, including native birds like the wedge-tailed shearwater.” An additional non-native species is the axis deer, first brought to the islands in the 1860s as a gift for the king; with no predators to control them, they’ve spread, and large herds of them can decimate native plant populations. The deer also trample across the beaches and dunes, collapsing the shearwaters’ burrows and sometimes burying the birds alive.

The Nature Conservancy, which owns the 921-acre Mo’omomi Preserve where the project is taking place, has removed sections of kiawe from the beaches to restore the dunes—about 12 acres in total—but acknowledges that some of the species are here to stay. Rather than trying to eliminate the deer, for example, they’ve simply fenced off the newly cleared beaches and dunes to keep the deer away and allow native grasses to take hold.

Since the work began, the Conservancy has counted almost 2,000 shearwater nests on the dunes. Scientists who tag and track the birds say that most of them—more than 90%—were hatched on the preserve.