A team of wildlife experts should be arriving on Midway Atoll from Laysan Island this week on a U.S. Fish and Wildlife Service mission meant to secure the survival of the Laysan teal.

They hoped to catch about two dozen of the birds, sometimes called Laysan ducks, for relocation to Midway Atoll on the theory that having two healthy populations in different locations reduces the threat of extinction if a disaster strikes the home population.

The ducks are considerably smaller than the Hawaiian duck, or koloa, and not much bigger than a fat pigeon.

The birds have the name of the island that has long held the only wild population of the animals, but Laysan ducks weren't always just from Laysan. Fossil evidence shows they were once found throughout the Hawaiian archipelago, including the main Hawaiian Islands.

But these birds, while stealthy when scientists pursue them, are pretty clueless when left alone, making them vulnerable. It is assumed that when rats, which prey on eggs, chicks and perhaps even adult ducks, arrived in the main Hawaiian Islands with the first humans, the teals' days were numbered.

There are a few in captivity here and there, but biologists have long wanted to establish a wild population outside the small, rat-free island of Laysan, a sandy speck of land about halfway up the 1,000-mile-long Northwestern Hawaiian Islands. At Midway, rats have been eradicated and there are facilities for keeping an eye on the birds, so scientists have dug a few ponds and planted plugs of plants the ducks might like.

Last year, 20 young ducks were moved from Laysan to Midway's Sand Island. Nineteen of them survive today, and most of the females produced eggs. Either nine or 10 (they're stealthy, after all, and hard to count) chicks are surviving, too, and several eggs are still being incubated by their mothers, according to Beth Flint of the U.S. Fish and Wildlife Service.

It means the ducks have increased their number by 50 percent in just their first year at Midway — a hopeful sign for the future.

The 2004 batch ended up with only six females, so this year, the bird team, led by duck researcher Michelle Reynolds and veterinarian Thierry Work, are trying to even the sexual landscape.

If they have enough birds, they plan to establish a second Midway population on Eastern Island, across the lagoon from Sand Island.

If you have a question or concern about the Hawaiian environment, drop a note to Jan TenBruggencate at P.O. Box 524, Lihu'e, HI 96766 or jant@honoluluadvertiser.com. Or call him at (808) 245-3074.