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> Newell's Shearwater
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| Population
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Photo by Richard Podolsky.
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Newell's Shearwater
(Puffinus auricularis newelii)
A great lover of the open ocean squalls that churn up its food, and well-known by the Pacific tuna industry for its association with tuna and large billfish, this species is pelagic, found flying where the thermocline reaches deep and the ocean measures more than 2,000 meters. Although time on shore represents only a small fraction of this bird's life, the breeding grounds have proven to be its "Achilles' heel". Serious population declines are attributed to degraded island habitat, collisions with power lines at night, fatal attraction to lights, and depredation by introduced land predators.
Identification
A small shearwater, black on upperparts sharply contrasted with white underneath. From above, white undersides come up on sides of rump giving appearance of white patches above tail. In flight shows classic shearwater flight with several quick flaps followed by a stiff-winged glide low over the water.
Distribution and
Population Trends
A highly pelagic species, Newells' Shearwater can be found in the deepwater regions of the Equatorial countercurrent all year round, to the south (up to 25 degrees N), and east (to about 120 degrees W) of the Hawaiian chain. Its range extends during "El Ni?o" events. It breeds only on the mountains of the Hawaiian islands, the most important of which is Kauai and it remains in Hawaiian waters from April through October. The population was estimated at 84,000 individuals from offshore surveys in the mid-1990's, but it seems to be undergoing a startling decline, with a 60% reduction in birds using Kauai during the 1990's.
Ecology
Newell's Shearwaters forage in association with big predatory fish (e.g. tuna), which push smaller prey species up to the surface, enabling the birds to plummet into the schools from their aerial vantage points. They can swim underwater, probably down to 10 meters, and swallow multiple prey items. They are not seen scavenging. Food items are not yet well known, but include fish, plankton and squid. They like to frequent incoming oceanic storm fronts that churn up rich food resources. Nests are found at higher elevations in burrows or deep crevices in forests where the birds lay their single egg. Pushed to extremes to avoid predation by pigs, mongooses and cats, they now nest almost entirely on slopes that exceed 65 degrees.
Threats
Like many island breeding species, Newell's Shearwater populations have been decimated over the years by hunting, habitat loss, avian malaria, and nest depredation by introduced predators. This latter threat is now the most serious one facing the species. The eggs, young, and adults are vulnerable to attack by introduced cats, rats, mongoose, pigs, and Barn Owls. Loss and degradation of breeding habitat often from the effects of introduced pigs and invasive plants and insects are also ongoing problems. Effects of urbanization, including collisions with power lines during their nocturnal flights, and the fatal behavior of encircling city lights, are also cause for concern as hundreds of birds are killed annually from these factors.
Conservation
The species was federally listed as Threatened in 1975. The Hawaii Division of Forestry and Wildlife has initiated surveys to locate breeding colonies on Kauai. An experiment using call playback techniques developed by Audubon's Seabird Restoration program in the Galapagos Islands, demonstrated that the Galapagos Petrel can be lured to nest in artificial burrows, a tool that may prove useful to relocating breeding pairs of Newell's Shearwaters into predator-free areas in the future.
What Can You Do?
The Endangered Species Act has helped protect the Newell's Shearwater and made it possible to learn critical information about its biology. Audubon continues to work to ensure that this vital legislation is being used to protect our publicly-owned wildlife resources. Check out http://www.audubon.org/campaign/ to learn of the latest news about the Endangered Species Act and how you can help. To learn more about other species protected under this legislation, visit: http://endangered.fws.gov/
Join Hawaii Audubon Society. A chapter of National Audubon, the Hawaii Audubon Society works to protect and educate people about Hawaii's birds. For more information visit http://www.audubon.org/states/hi/
References
Ainley, D.G., T.C. Telfer, and M.H. Reynolds. 1997. Townsend's and Newell's Shearwater (Puffinus auricularis). In The Birds of North America, No. 297 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D.C.
Birdlife International. 2000. Threatened Birds of the World. Lynx Edicions, Barcelona.
Day, R.H., and B. A. Cooper. 1995. Patterns of movement of Dark-rumped Petrels and Newell's Shearwaters on Kauai. Condor 97:1011-1027.
Ehrlich, P.R., Dobkin, D.S., and D. Wheye. 1992. Birds in Jeopardy. Stanford University, Stanford, CA.
Harrison, C.S. 1990. Seabirds of Hawaii. Cornell University Press, Ithaca.
Harrison, P. 1983. Seabirds: An Identification Guide. Houghton Mifflin, Boston.
Pratt, H.D., P. L. Bruner, and D. G. Berrett. 1987. The Birds of Hawaii and the Tropical Pacific. Princeton University Press, Princeton, NJ.
Shallenberger. R.J. 1984. Hawaii's Birds. Hawaii Audubon Society, Honolulu, HA.
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