In April along Oahu’s windward shore, several honu — threatened Hawaiian green sea turtles — began hauling out of the shorebreak to nest on the mile-long white sands of U.S. Marine Corps Base Hawaii Training Area Bellows Beach.

It was the first time such behavior has been documented there.

And about a month ago, 3-inch-long hatchlings began emerging from the sand and hele’ing down, flippers flapping, to the sea.

Last week in the most recently observed nocturnal hatching, a few baby honu headed in the wrong direction — inland. Many of those honu were saved and redirected by staff and volunteers of MCBH, said Lt. Col. Tim Pochop, director for environmental compliance and protection, and Lance Bookless, senior natural resources manager, at MCBH Kaneohe Bay. They have been monitoring the honu nests in partnership with U.S. Fish and Wildlife and the National Oceanic and Atmospheric Administration.

”As the hatchlings emerge, they’re attracted toward the moon,” Bookless said, “but there’s a lot of street lights and house lights behind the beach.”

“We were able to recover about 12, but not all of them unfortunately,” Pochop said.

While they can’t yet say why nesting occurred at MCBH Bellows this year for the first time, it was possible that mother honu might have been drawn to the beach in April because it was closed, like all beaches statewide, due to the new coronavirus pandemic, Pochop and Bookless said.

“So initial nesting seemed to occur before we had a lot of recreation (return to) the beach when the public came back in May,” Pochop said.

By then, the MCBH conservationists had identified 15 nests and roped them off.

On the other hand, he added, MCBH Kaneohe Bay’s North Beach on Mokapu Peninsula “has been open this whole time for surfing and watersports,” and honu have nested there, as well as at Fort Hase Beach and at Bellows Marine Air Force station on the other side of Waimanalo Stream from MCBH Bellows.

Typically, honu will go back to where they hatched to nest, Bookless said, but many Hawaiian green sea turtles, the majority of which nest in the French Frigate Shoals in the Northwestern Hawaiian Isles, have no dry sands to return to as a result of climate change and recent devastating storms.

“A lot of turtles have been displaced by the hurricane that destroyed their primary nesting grounds in the French Frigate Shoals two years ago, combined with sea level rise over little atolls (in the Northwestern Hawaii Islands),” he said.

“We don’t know where these turtles came from originally, but that’s part of the post-excavation work,” Bookless said.

After nesting and hatching ends, he said, scientists will excavate the nests and take DNA samples “of hatchlings that didn’t make it, to get a sense of who the parents are and where they came from.”

For instance, Pochop said, “We have a lot of turtles that reside in the Kaneohe Bay area, and some that take up residence in fishponds, and those ones, I guess, are migrating out to French Frigate Shoals for nesting, then maybe redirecting and looking for nests on this island.”

Some of the honu nesting at Bellows also may have been imprinted to return there, according to Joe Murphy, director of Malama Na Honu, a nonprofit conservation organization.

“About 30 years ago, Sea Life Park and Maui Aquarium began releasing turtles that had been rescued and they marked the main Hawaiian islands as their birthplace,” Murphy said. “A lot of turtles were released at Bellows Beach.”

There is only so far that conservation scientists can go to rescue hatchlings, however.

“We can’t get involved with the course of nature,” Pochop said. “We don’t intervene when hatchlings are eaten on the sand by nocturnal ghost crabs that get to the size of baseballs, which tear their heads off and eat their innards, but if a turtle is disoriented we can reorient them.”

Last week, that involved wearing gloves, putting the turtles in a bucket with sand from the beach, and “letting them walk into water themselves,” Pochop said. “That’s how they imprint themselves and know when to come back, 20-25 years later,” when they’ve matured and are ready to nest.

For the most part, honu haul up to nest at night, and honu hatches are triggered “when ambient temperatures hit the right threshold and the sand temperature comes down, usually at night, when there are less bird predators, sometimes in the rain,” Bookless said.

But hatchlings who make it into the sea are then preyed on by fish, including sharks, he added.

All in all, it was exciting but “baffling,” Bookless said, to “suddenly to have this huge number of honu come ashore to nest.”

October is generally the end of nesting season, he said.