Newell's Townsend's Shearwater

Puffinus auricularis newelli

Description

Newell's Townsend's shearwater (Puffinus auricularis newelli; also known as 'a'o; formerly known as Newell's manx shearwater) is a gull-sized seabird, 12-14 in (30.5-35.6 cm) long, with a wingspan of about 33 in (83.8 cm). Upper parts, including the crown, neck, back, wings, and tail, are glossy black. The throat, breast, and wings are white. The black bill is sharply hooked at the tip. Feet are webbed and distinctly pink; toes are characteristically gray with well-developed claws adapted for burrow excavations and climbing.

Behavior

Newell's Townsend's shearwater glides long distances close to the surface of the water. It is a good swimmer and feeds on fish, plankton, and sometimes ship garbage. It nests in burrows on remote islands or sea cliffs. The nesting burrows are used year after year, generally by the same pair.

Habitat

Newell's Townsend's shearwater uses its nesting habitat for nearly nine months of the year, April through November. Nest sites are typically in steep mountainous terrain, 500-2,300 ft (152.4-701 m) in elevation, in or near dense stands of ferns. Ferns help stabilize burrows against soil erosion and offer protection from predators and the elements. Tree cover is usually moderate to light, and tree roots serve to shore up burrow entrances and discourage rooting by feral pigs.

Rainfall in nesting areas ranges from 40 to 100 in (101.6 to 254 cm) annually. The species typically requires an open, downhill flight path to get airborne and thus favors ridge crests or embankments. There may be other subtle nesting habitat requirements (such as the slope of the area, humidity, and temperature), but these remain unknown.

Distribution

This species nests and breeds only on the Hawaiian Islands. It was first described in 1900 from a specimen obtained on Maui by Brother Mathias Newell in 1894. How far Newell's Townsend's shearwater ranges from land is unknown. Nonbreeders and subadults are thought to concentrate near the equator, where currents are rich with oceanic nutrients. Some of the species are thought to pass through the north-central equatorial region on their way to breeding grounds. There are breeding colonies on Kauai, Hawaii, Molokai, and possibly Oahu. Surveys in 1988 found at least 57 breeding pairs of the species in three populations. Newell's Townsend's shearwater inhabits the islands from April to October or November and is mostly absent the remainder of the year.

Threats

The greatest limiting factor for Newell's Townsend's shearwater is predation by pigs, cats, black rats, and, most of all, the mongoose. Already established on the other main islands, the mongoose may have reached the island of Kauai as well.

The species normally flies to and from nesting grounds only after dark, and fledgling shearwaters apparently have a strong attraction to light, possibly because of a natural luminescence of their food supply or because they navigate using the reflection of the moon and starlight on the water. Manmade lighting induces night blindness in shearwaters, causing them to fly into utility wires, poles, trees, and buildings. Between 1978 and 1981, more than 5,500 shearwaters fell on Kauai's highways, athletic fields, and hotel grounds. In 1978 biologists initiated a Save-Our-Shearwater campaign.

Conservation and Recovery

During the fall fledgling season, residents are asked to pick up fallen shearwaters and deposit them at an aid station, where injured birds are treated before being released. Without this successful program, a larger number of birds would die. Attempts to shield the upward glare of streetlights have not been totally effective, and research is under way to develop lights that will not attract this species.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
(503) 231-6121
http://pacific.fws.gov/

Pacific Remote Islands Ecological Services Field Office
300 Ala Moana Blvd., Room 3-122
P. O. Box 50088
Honolulu, Hawaii 96850
Telephone: (808) 541-1201
Fax: (808) 541-1216

References

Scott, J. M., et al. 1988. "Conservation of Hawaii's Vanishing Avifauna." Bioscience 38 (4): 238-53.

U. S. Fish and Wildlife Service. 1983. "Hawaiian Dark-Rumped Petrel and Newell's Manx Shear-water Recovery Plan." U. S. Fish and Wildlife Service, Portland.