"It's so exciting to have these birds out here surviving and nesting," said wildlife biologist John Klavitter of the U.S. Fish and Wildlife Service, who works at Midway.

He said there has been only a single fatality among the flock, and that happened in November when an albatross attacked one of the new arrivals. The others remain healthy and are foraging on their own, eating seeds, leaves, algae, cockroaches and other bugs.

One of the three nests discovered two weeks ago contains a clutch of nine eggs and another has six. Biologists have been unable to get a good look at the third nest.

The incubation period is 30 days, and the eggs could hatch in another two weeks. "We're hoping to see some ducklings. It's not uncommon for Laysan ducks to lay infertile eggs," Klavitter said.

Biologists fear these Laysan duck eggs are infertile because they were laid by a younger female that probably did not mate. Photo by John Klavitter

Before the Midway transfer, the ducks were found only on 1,000-acre Laysan Island, where the duck population is estimated at 400 to 600. Fossils recently have revealed the birds

once inhabited Hawai'i, Moloka'i, Maui, O'ahu and Kaua'i, and 400-acre Lisianski, also in the Northwestern Hawaiian Islands.

The ducks have had several close brushes with extinction. Humans who came to Laysan in the 1890s to mine guano killed an estimated 300,000 birds within six months and introduced rabbits that devastated the vegetation, creating desertlike terrain. Three species — the Laysan rail, the Laysan honeycreeper and the Laysan millerbird — became extinct, and by 1911 records showed there were only 11 Laysan ducks left.

The bird was listed as an endangered species in 1967 under the Federal Endangered Species Act.

In 1993, drought and disease dropped the Laysan population to just 50 ducks.

"It brought the point home that it's really important (to establish new populations) because some catastrophe could happen again and we could lose all the birds," Klavitter said.

Midway's three islands were chosen as a reintroduction site because they lie within the duck's presumed former range, are free of rats and other predators and provide a good environment for monitoring the flock.

Before the ducks arrived in October, volunteers and staff from the Fish and Wildlife Service and the U.S. Geological Survey spent 18 months making preparations on Midway's 1,200-acre Sand Island, removing non-native plants, excavating nine shallow freshwater seeps and planting native bunch grass for nesting. The ducks were placed in aviaries for a few weeks before their release, and radio transmitters were attached to each bird for tracking.

Supplemental food was provided until just a week ago, Klavitter said, but most of the ducks had become self-sufficient.

Klavitter said biologists have been tracking ducks on Laysan that were the same age as the Midway birds, but only half had survived due to greater competition for resources and limited food and water.

Depending on the success of this year's breeding season on Laysan — which runs from February to August — wildlife biologists hope to capture 30 young ducks in October and transfer them to Midway's Eastern Island, Klavitter said. In a good year, the Laysan population will produce 50 to 100 hatchlings, he said.

Working with Klavitter on the Laysan duck project at the Midway refuge are U.S. Geological Survey wildlife biologists Michelle Reynolds, Mark Vekasy and Leona Laniawe.