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Nature Calls
Shirley Gerum
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STAR-BULLETIN / 2007
A shearwater chick peers through the foliage hiding its nest on Black Point near Diamond Head.
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Endangered island birds need our help to survive
The early Hawaiians knew the birds we call Newell's shearwaters. Naming them was easy: The birds' call sounds like "ah-oh," so the early Hawaiian settlers called them ao. Bird watchers have referred to the lively sounds heard around the nesting colonies as "jackasslike braying" or "crow calling."
Today's natural resource experts recognize this bird as a unique subspecies of shearwaters endemic to the Hawaiian Islands and nowhere else. They are listed as "threatened" on the Endangered Species List.
It's obvious that we humans are part of the problem -- especially those who arrived after Capt. Cook, bringing the rats, cats, mongoose, cattle, sheep and dogs that would add to the decline of the ao.
The birds were once abundant on all of the main islands but now nest primarily on Kauai, which claims 75 percent of the world's population. A few probably nest in remote areas of other islands.
In 1995 the U.S. Fish and Wildlife Service estimated the population of Newell's shearwaters at 84,000, with a breeding population of approximately 14,600 pairs. Recent data from radar surveys reveal a decrease of 50 to 70 percent between 1993 and 2001.
Shearwaters are birds of the open tropical seas and offshore waters near breeding grounds. During their nine-month breeding season (April through November), they live in burrows under ferns on mountain slopes, but some are left literally clinging onto vertical cliff faces and nesting in rock crevices.
Another ground-nesting marine bird, the native endemic Hawaiian petrel (uau), is also on the Endangered Species List. (Its name also comes from the sound it makes -- "oo-ah-oo.")
The petrels also once nested on all the main islands except Niihau. They're now restricted to Haleakala Crater on Maui, with smaller numbers nesting on Kauai, Lanai and the Big Island.
Petrels are generally seen close to the main islands only during breeding season, according to the Hawaii Audubon Society. Otherwise, they cruise the ocean, their flight characterized by high, steeply banked arcs and glides. The adults feed on squid, fish and crustaceans and pass food to newly hatched chicks by regurgitation.
WITH both of these Hawaiian birds, as our numbers went up, theirs went down. As more people have moved to these islands, building homes, businesses and roads and bringing animals, the number of these birds has steadily decreased.
We brought something else that has been blamed for a large number of bird deaths: 24/7 artificial light.
Fledglings typically take their first flights at night, leaving their upland nest sites and instinctively seeking natural light shining on water to help them find the sea. Artificial lights leave them disoriented and exhausted as they collide with buildings and power lines.
Falling to the ground, these birds become prey to cats, rats, dogs and mongooses. They are hit by cars or die of injuries or dehydration. Combined with a naturally low reproductive rate and lack of natural defenses, these additional threats greatly increase the vulnerability of these seabirds.
The Fish and Wildlife Service has worked with the community to reduce nonessential lighting between Sept. 15 and Dec. 15, when the young birds are flying toward the open sea. The Kauai Island Utility Cooperative darkens lights, shields streetlights so they don't shine upward and installs large balls on power lines to help birds avoid the wires. Lights at Chevron's Port Allen facility, traditionally a significant site for shearwater "fallout" on Kauai, have been retrofitted to reduce light leakage, all to save these birds.
What can the rest of us do? Volunteer for the annual Audubon Society bird count; remind ourselves, when visiting Kauai, to dim lights during this time; support spaying and neutering programs for cats and dogs; and get involved with other programs in progress.
The birds can only remind us by shouting their names.
The rest is up to us.
Shirley Gerum teaches botany, ethnobotany and environmental science at Chaminade University. Her column runs on the last Monday of the month. E-mail her at
features@starbulletin.com.