The Newell's shearwaters of Kilauea Point.
To date, only four nests of this burrow-nesting bird have been found, but refuge biologist Brenda Zaun remains optimistic. "Conducting population studies of this species is extremely difficult," she says. "Looking for their hidden burrows is like looking for a needle in a haystack, and you have to be careful not to destroy the haystack during the search. I suspect there are more here; I just haven't found them yet."
Listed as threatened in 1975, this endemic Hawaiian seabird is small with black and white plumage. Like many seabirds, the Newell's shearwater comes to land only to breed and nest, raising a single chick each year. Burrows excavated by the birds serve as nest cavities. Most of the world's populations of Newell's shearwaters nest in colonies along steep mountain ridges and valleys in the interior of Kaua'i. These areas are largely inaccessible to humans but not to non-native predators, such as feral cats, pigs, and rats. The birds feed at sea during the day, fly to their inland burrows after dark, and return to sea well before dawn.
Seabird experts believe that perhaps 90 percent of Newell's shearwaters nest on Kaua'i. Some of the other main Hawaiian Islands may have very small populations, but they have not been confirmed. Based on recent surveys, the population on Kaua'i appears to be declining.
So why would a species that nests in remote mountain habitats nest at a coastal refuge? "The individuals nesting at the refuge are very likely descendents of Newell's shearwaters that were brought here 30 years ago as eggs and cross-fostered by the much more common wedge-tailed shearwater (Puffinus pacificus)," Zaun explains.
In the late 1970s, a bold experiment was conducted over a three-year period. The highly successful experiment took 90 Newell's shearwater eggs from their mountain burrows and carefully transported them to the refuge at Kilauea Point, where they were placed under incubating wedge-tailed shearwaters. Of these, 67 chicks fledged. Zaun and others believe that at least some of those birds returned and nested at the refuge, and the nesting individuals known today are most likely progeny from those original birds.
Until a few years ago, very little was known about the nesting habits and behavior of Newell's shearwaters. Using non-invasive monitoring equipment, Zaun has been able to increase exponentially our knowledge of the species[degrees] With an active infrared camera system at the burrow entrances and passive integrated transponders (PIT) tags on the adults, she was able to learn when the birds arrive on land, the length of courtship and nest preparation prior to egg laying, the length of incubation and individual incubation shifts, the length of the chick rearing period, feeding strategies, and the degree of parental investment during the reproduction period.
The infrared camera system has proven to be an invaluable resource, especially at two artificial nest boxes. This setup facilitates monitoring and ensures that the equipment is effective. The camera system records everything that momentarily breaks an invisible infrared beam across the burrow entrance. Species photographed at the burrow entrance include feral cats, rats, Hawaiian geese, small passerines, geckos, and spiders. The photos of cats and rats have reinforced the belief that maintaining predator control at Kilauea Point is paramount to protecting Newell's shearwaters and other native species that nest on the refuge.
Although these seabirds fly to and from land during darkness and nest almost exclusively in remote areas inaccessible to people, the Kaua'i community is well aware of Newell's shearwaters. For decades, people have been finding them on the island's roadways, yards, and ball parks. Unfortunately, the fledglings have a strong attraction to lights and will exhaust themselves flying around them before coming to ground, often colliding with buildings, trees, and utility lines along the way.
Three decades ago, Hawaii's Department of Land and Natural Resources began the "Save our Shearwaters" Program. The program uses community support to help save injured or stranded birds. People who find a live bird are encouraged to pick it up and take it to the nearest tire station for the appropriate care. More than 31,000 Newell's shearwaters and other seabirds have found their way back to the sea thanks to this unique program.
Currently, the U.S. Fish and Wildlife Service, the state of Hawaii, and private organizations are working on a plan to minimize the negative impacts that lighting and other attractants have on the shearwaters, with the hope of providing safer routes for the birds to travel from the mountains to the sea and back again.
Mike Hawkes was the manager for the Kaua'i National Wildlife Refuge Complex before becoming the manager at Buenos Aires National Wildlife Refuge in Arizona. He can be reached at 520-823-4251 x102 or email@example.com.
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|Publication:||Endangered Species Update|
|Date:||Jan 1, 2009|
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