The ground-nesting seabirds were the victims of an attack by a loose dog, which was captured roaming the dunes with a shearwater in its mouth.
Sixty adult wedge-tailed shearwaters were found dead at The Nature Conservancy’s Mo‘omomi Beach Preserve on the island of Moloka’i.
“We’re all devastated,” said Ed Misaki, the Conservancy’s Moloka‘i Program Director. “These were all adult birds trying to establish their nests. This will affect the ability of this thriving seabird colony to continue to grow.”
Wedge-tailed shearwaters — or ‘ua‘u kani — are large, dark-brown migratory birds with a black-tipped dark-gray bill. The birds live all their lives at sea and come ashore only to breed. Returning to the same site each year, they nest in shallow sand burrows, three to six feet in length.
Because the birds live underground and are awkward and helpless on land, they are easy targets for dogs and other predators.
According to state wildlife biologist Fern Duvall, all 60 of the birds were sexually mature adults at least seven years of age. They had recently begun arriving at the preserve to establish their nests for the breeding season, which extends from March through December.
“It’s a real tragedy,” said Duvall, who has been banding the shearwater population and conducting annual nest counts at Mo‘omomi since 2000. “These are long-term monogamous birds that require seven years before they become sexually mature adults. So we have lost a good portion of the breeding population here.”
The Conservancy’s Mo‘omomi Preserve is a rare, intact coastal sand dune ecosystem located on the islands’ northwest coast. When the Conservancy first established the preserve in 1988, shearwaters and other ground nesting sea birds had all but disappeared. Then, in 1999, Conservancy staff discovered three sand burrows and began implementing a year-round monitoring and predator control program to protect the birds from rodents, cats, mongooses and dogs.
The program had been so successful in creating a safe haven for the shearwaters that last year the nest count had grown to 418, with a further increase expected this year.
Despite the loss, Duvall and the Moloka'i staff are optimistic that the colony will be able to recover.
"The nesting season has just begun," said Duvall. "And one night after the attack, we banded 94 healthy adults — and found two more that were already wearing bands." It was the largest number of birds ever banded in a single session.
"That's the good news," said Misaki. "The birds are still coming in."
The Nature Conservancy is a leading conservation organization working around the world to protect ecologically important lands and waters for nature and people. The Conservancy and its more than 1 million members have protected nearly 120 million acres worldwide. Visit The Nature Conservancy on the Web at www.nature.org.