Mo‘omomi Preserve had long been shortlisted for preservation by TNC, not only because it represented one of the largest and last coastal dune ecosystems in Hawai‘i, but also because it was known to be rich in cultural and natural resources. The Conservancy had an opportunity to acquire the property from the former Moloka‘i Ranch in 1988. The 921-acre property held the most expansive intact coastal dune ecosystems in the main Hawaiian Islands—a habitat that was largely lost to development on the bigger islands. Mo‘omomi still had an open landscape, but the dunes had been invaded by invasive plants, especially the kiawe, a thorny mesquite tree that was crowding out native vegetation and preventing wedge-tailed shearwaters from nesting.

The shearwaters weren’t on the radar yet, says Ed Misaki, TNC’s director of programs on Moloka‘i. The goal at Mo‘omomi has always been to preserve the dunes and restore the coastal ecosystem, which includes low-lying native grasses and shrubs that have largely been lost in more developed parts of the islands.

The kiawe trees, which grow 6 to 25 feet tall at the preserve, are so thick and dense that local crews hired by TNC must work from the outside in to remove them, cutting back the outer branches until they reach the trunk, says Misaki, who has worked for the organization for 35 years. The stump is treated to prevent regrowth, and the branches are shredded in a wood chipper. The mulch is spread across the area to stabilize the bare ground until native plants can take hold.

As crews cleared the area of the trees, ‘aki‘aki, a low-lying native grass, began creeping back in, blocking out invasive plants and setting the stage for other native species to regrow. Misaki refers to Mo‘omomi’s management strategy as “passive restoration”—giving natives room to recover and letting them move in, versus trying to replant everything. Native dune habitats would gradually rebuild themselves when given relief from the invasives. “Nature is really telling you what to do,” he says.

In 1999, less than 10 years after TNC began restoring the preserve, the first shearwater nest at Mo‘omomi was discovered. Misaki said he was surprised; it was the first time seabirds had been found nesting in the preserve. “That was an exciting moment,” he says. “Wow, the birds want to nest here.” Almost immediately, a protection plan was developed to determine threats to the birds. A year later, there were 20 nests. Workers continued clearing more kiawe. The year after that there were 75 nests.

But as the nesting wedge-tailed shearwater population grew, the staff saw signs of mortality among the birds. Adults and chicks were being killed by feral cats, stray dogs and mongooses—all non-native species. Predator control has been part of the preserve’s restoration plan since the first nest was found.

Conservancy staff also realized that axis deer—another invasive species—were part of the problem as well. As the deer ate native plants near the wedge-tailed shearwaters’ nesting sites, they trampled the fragile dunes, causing the burrows to collapse, burying the birds alive. In 2006, TNC installed a 1.5-mile fence near the dune. It was designed to keep predators and deer out of the nesting area, and withstand the salt air and coastal wind.

Removing more kiawe helped reduce the effectiveness of predators, too. Workers pulling out the tangled, thorny trees in one stand found piles of wings underneath. Cats had been using the trees as cover to stalk the seabirds, then returning to their hideouts to eat their kill. “When we removed the kiawe, we gave the feral cats less habitat to attack the birds from,” says Russell Kallstrom, TNC’s Moloka‘i field information coordinator and a native of the island.

By the time Penniman led his first banding effort in 2007, Mo‘omomi Preserve hosted hundreds of nests. And by 2009, clusters of them were visible on Google Earth. “We [could] see our work from space,” says Kallstrom. “We were really making a difference.”