MO'OMOMI, Moloka'i — The nighttime wailing of wedge-tailed shearwaters is returning to Mo'omomi in a growing chorus.

The seabirds are establishing a new colony in the Moloka'i coastal preserve, with 307 active nests counted during the most recent breeding season, compared with only three nests less than 10 years ago, according to The Nature Conservancy, which manages the 921-acre area.

State wildlife biologist Fern Duvall said the shearwater resurgence is due to The Nature Conservancy's efforts to control weeds and predators. He said the migratory birds can breed in large numbers only in predator-free areas and are all but gone from the main Hawaiian Islands.

Wedge-tailed shearwaters are known in Hawai'i as 'ua'u kani, which means "moaning petrel." The large, dark-brown birds have a dark-gray bill with a black tip and live at sea, coming ashore only during the March-to-December breeding season.

The monogamous pairs generally return to the same nest site each year, using shallow sand burrows. At night, pairs sit head-to-head, vocalizing with two-part wailing duets.

Shoreline development and predation by rodents, cats, mongooses and dogs have deprived the seabirds of their natural coastal nesting grounds, The Nature Conservancy said.

Ground-nesting birds at Mo'omomi had all but disappeared when the conservancy began managing the area in 1988. Ed Misaki, director of the group's Moloka'i program, said shearwaters first reappeared in 1999, with three nests discovered.

A year-round monitoring and protection program was implemented, and Duvall has been helping count nests since 2000 and bands chicks as they mature.

Counts showed 17 nests in 2000, more than 100 nests by 2004, and 254 in 2006. The 2007 count was 307 active nests.

The Mo'omomi Preserve is a rare intact coastal sand dune ecosystem.

Feral cats have been the largest threat to ground-nesters, Misaki said. "As we cleared away the brush, we found lots of bird bones and realized that the cats had used the trees as staging grounds for their attacks," he said

Large stands of kiawe were removed, allowing for natural regeneration of native plants. Predator monitoring and control efforts help prevent feral cats, rats and mongooses from preying on eggs, chicks and adults.

To reduce disturbance by humans, walking trails were rerouted away from nesting areas.

Misaki said the rate at which the shearwater population is growing, faster than through just eggs laid, indicates the birds are recruiting new adults to Mo'omomi.

Duvall said there's hope other seabirds will take up residence there. "Colony-nesting and the activity of a thriving colony can bring in other birds, including other native or endangered species that have been lost," Duvall said. "There's no reason albatrosses couldn't be repopulated here."