WatchList Species Account for Newell’s Shearwater |
Qualifies for the list as a Red List Species
|Photo: Jack Jeffrey
Sometimes treated as one of the eight races of the P. puffinus complex or as a well-marked race of P. auricularis, the Newell’s Shearwater breeds only in a few colonies on the Hawaiian Islands, principally in the mountains of mongoose-free Kauaʻi, where there has recently been a significant decline of some 60%, from 1993 to 1999. Overall the species is thought to have declined by 50% in the last 47 years, primarily due to loss of nesting habitat.
Newell’s Shearwater breeds in colonies from 525 to over 3,900 feet in burrows on steep slopes. Prior to the introduction of predators, its nesting habitat was not restricted by gradient. Only about 20 colonies are known. Some of these colonies are far inland, up to eight miles on Kauaʻi .
During the nonbreeding season, Newell’s Shearwater is highly pelagic, and is found in tropical and subtropical waters overlying depths over 6,500 feet to the east and south of the Hawaiian Archipelago.
Though little is known about food items taken, squid appears to be an important part of the bird’s diet.
A major mortality factor for the species is collisions with power lines on Kauaʻi , which accounts for the deaths of hundreds of birds each autumn. Hurricanes devastated the forests of Kauaʻi in 1982 and 1992, and since then, numbers of the bird on the island have been declining. Habitat degradation and predation by cats, rats, dogs, pigs and the introduced Barn Owl further threaten the species.
The overall population has been estimated at 84,000 individuals, but surveys in colonies will never provide an adequate estimate, since the terrain is too difficult to allow much work to be done. Newell’s Shearwater is listed as federally threatened under the Endangered Species Act, and BirdLife International classifies it as endangered.