KAPALUA, Maui — For most of his 74 years, Isao Nakagawa considered Hawea Point in Kapalua as simply a good place to catch bait fish, not as nesting habitat for wedge-tailed shearwaters.

Then, about seven years ago, he discovered the aftermath of a massacre at the dwindling seabird colony.

"One day I found 22 dead birds. That really got me. I couldn't stand it," said Nakagawa, a retired shop supervisor for Maui Land & Pineapple Co.'s Honolua plantation.

The marauders were cats or dogs, and Nakagawa was moved to launched a one-man campaign to remove predators from the area and protect the shearwaters, which spend most of their lives on the open ocean, coming ashore in late March and April to nest in burrows in the sandy soil and rocky crevices, and between the roots of ironwood trees.

Wildlife officials say that with Nakagawa's help, the number of surviving fledglings each season has grown from zero to the 100-plus young birds that were banded last year. The Napilihau man's efforts also have inspired volunteers to adopt wedge-tailed shearwater colonies elsewhere on Maui, where similar successes are being reported.

"Isao's a superhero," said state wildlife biologist Fern Duvall of the Department of Land & Natural Resources. "Here is somebody who has really made a total difference as a single individual doing this."

Wedge-tailed shearwaters are known in Hawaiian as 'ua'u kani, or "moaning birds," for their ghostly nocturnal vocalizations. Although not endangered, they are protected under state law and the federal Migratory Bird Treaty Act. The seabirds are estimated to number 270,000 pairs in Hawai'i, with most found in the Northwestern Hawaiian Islands. A small number choose riskier nesting sites on the main islands, where they are vulnerable to habitat loss from development and attack by dogs, cats, mongooses and rats.

"A single cat can go through a colony and hit all the burrows in one or two nights," Duvall said.

It takes four to five years for the seabirds to reach sexual maturity, and each pair lays only a single egg each year. If the egg is destroyed or doesn't hatch, the pair's breeding season is over.

Hawea Point is now the largest of seven known 'ua'u kani colonies on Maui, according to Duvall. Before Nakagawa stepped in, the seabirds were scarce at the site due largely to predation by feral cats and their domesticated cousins that inhabit nearby homes. Another problem was the fishermen, campers and trail walkers who brought their vehicles into the area and let their dogs run loose.

Nakagawa began by approaching Hawea Point residents Craig and Maja Ramsey, who allowed him access to their property and bought several cat traps for him. The Ramseys later deeded to the Maui Open Space Trust a makai easement containing nesting territory. The land is now controlled by the Maui Coastal Land Trust.

Nakagawa arranged for barriers to keep vehicles out and for signs put up by Duvall advising people to keep their dogs on leashes during the nesting season. The retiree checks the traps daily, turning over captured felines to the Maui Humane Society. He also picks up rubbish and spreads rodent poison to get rid of the rats.

"He's manned every single cat trap out there," Duvall said. "Initially, when I went out to see him, there were relatively few birds out there. Then in a year there were hundreds. Basically that entire colony's well-being and its spread are really due to his efforts."

Nakagawa knows the location of virtually all of the 275 nesting burrows at Hawea Point, and in 2005, he worked alongside Duvall to band 127 shearwater fledglings. "He was down on his hands and knees and he'd grab the birds and they'd bite him. His hands were bloody, but he was so happy," Duvall said.

The wildlife biologist said it is appropriate that an old-timer born and raised in the area has taken the seabirds under his wing.

"He represents a traditional view of these birds. He's a fisherman who knows that these birds were important as 'ahi or aku birds that in the past have shown Hawaiians where the 'ahi and aku were running," Duvall said. "The birds help you; you help out the birds."

Maui Land & Pineapple Co., which owns adjoining land at Hawea Point where the shearwaters nest, also has been inspired by Nakagawa's conservation work. The company is buying a dozen more traps and plans to remove some of the ironwood trees to make it easier for the seabirds, which are awkward on land, to reach their burrows, said Randy Bartlett, manager of ML&P's 7,400-acre Pu'u Kukui Watershed Preserve in the West Maui Mountains.

The rocky point is part of an 11.5-mile stretch of shoreline the company is restoring to create a 3,000-acre coastal preserve as part of its Kapalua development plans.

"It's great that a former employee is doing that on his own. If it hadn't been for his initiative, the colony would be nowhere near as healthy as it is. The work he's done has really helped that colony thrive," Bartlett said.

Reach Christie Wilson at cwilson@honoluluadvertiser.com.