Native shearwater population soars on Molokai

Living808

A small but steady population boom on Molokai is giving environmentalists a reason to cheer.

A Native Hawaiian seabird is making a comeback.

This past October, volunteers gently banded 122 wedge-tailed shearwater chicks in a single day at The Nature Conservancy’s Mo’omomi Preserve on Molokai.

Each band is numbered, and the data is entered in an international database to track the seabird’s slowly growing population.

“Seabirds in Hawaii once reigned over all the main Hawaiian Islands. Nowadays, they’re only found on the offshore islands, mostly because of predators,” explained Dr. Sam Ohu Gon, The Nature Conservancy senior scientist and cultural advisor.

Wedge-tailed shearwaters, or ‘ua’u kani, are large, dark-brown migratory birds with black-tipped dark-gray bills. They live their lives at sea and come ashore only to breed. Returning to the same nest site each year, wedge-tails nest in shallow sand burrows, one to two meters in length.

These birds are culturally and environmentally important to Hawaii.

“The seabirds eat fish that were growing as a result of the nutrients off the land. Then in their droppings, they fertilize the whole island,” Gon explained.

But shoreline development and predation by non-native species like rodents, cats, mongoose and dogs have deprived them of their natural coastal nesting grounds.

When The Nature Conservancy established the Mo’omomi Preserve in 1988, there were no shearwaters. But in 1999, they found three nests which grew to several hundred nests by 2007.

Then, this year’s good news: “The shearwater nesting colony at Mo’omomi has broken 1,000 active nests,” Gon said.

It’s thanks to human protection from predators. “As soon as it became apparent these shearwaters were present, we began to think about what is it they would need. They need an undisturbed coastal sand dune ecosystem,” Gon said.

Staff began implementing year-round monitoring and protection strategies. Predator monitoring and control efforts now prevent feral cats, rats and mongoose from preying on eggs, chicks and adults. Trails have been re-routed away from nesting areas to minimize human disturbance and the risk of crushed burrows.

The Nature Conservancy will be banding new chicks again in April, and environmentalists are excited to see the population numbers soar.

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