39th Meeting of the Pacific Seabird Group: Turtle Bay, HI, 7-10 Feb 2012. [abstracts]
BRYAN’S SHEARWATERS HAVE SURVIVED IN THE BONIN ISLANDS, NORTHWESTERN PACIFIC!
Kazuo Horikoshi*1, Masaki Eda2, Kazuto Kawakami3, Hajime Suzuki1, Hayato Chiba1, and Takashi Hiraoka4,
1 Institute of Boninology, Chichijima, Ogasawara, Tokyo Japan, hori AT ogasawara.or.jp; 2 Tottori University, Yonago, Tottori Japan; 3 Forestry and Forest Products Research Institute, Tsukuba, Ibaraki Japan; 4 Yamashina Institute for Ornithology, Abiko, Chiba Japan
The Bryan’s Shearwater (Puffinus bryani) is a new species described in 2011 based on a specimen collected in Midway Atoll in 1963 (Pyle et al. 2011). This specimen and another recorded at Midway Atoll in the early 1990s are the sole reliable records to date. Bryan's Shearwaters likely do not regularly breed in the Northwestern Hawaiian Islands because of the limited number of records. The Bonin Islands are subtropical oceanic islands located in the northwestern Pacific Ocean at a similar latitude to Midway. Since 1997, we have found six samples of remarkably small Puffinus shearwater (one rescued individual and five carcasses) which showed similar morphological characteristics to the Bryan’s Shearwater. In this study, we genetically and morphologically examined the Bonin samples and have confirmed that they are the Bryan’s Shearwaters. Since the latest sample was found on an islet to the north of Chichijima Island in 2011, the species have surely survived there. There is thus a strong possibility that the Bonin Islands provide their breeding grounds, although the exact locations remain unclear. Three of the examined individuals found on an islet off Chichijima Island were detected as carcasses preyed upon by Black Rats (Rattus rattus). Although attempts were made to eradicate rats on this island in 2008, there are various other rat-infested islands that could be breeding grounds for shearwaters. In any case, Bryan's Sheawater appears to be very rare and threatened in the Bonin Islands. For its conservation, detection of their breeding sites and rat eradication are essential.
UPDATED INFORMATION ON BRYAN'S SHEAWATERS (PUFFINUS BRYANI) IN THE NORTH PACIFIC OCEAN, WITH A LOOK TOWARD ITS CONSERVATION
Peter Pyle*1, Reginald David2, Bruce D. Eilerts3, Binion Amerson4, Matthew McKown5 and Abe Borker5
1 The Institute for Bird Populations, P.O. Box 1346, Point Reyes Station, CA 94956, USA, ppyle AT birdpop.org; 2 Rana Productions, Kailua-Kona, HI; 3 Arizona Department of Transportation, Phoenix, AZ; 4 Dallas, TX 75234; 5 Coastal Conservation Action Lab., U.C. Santa Cruz, CA.
A new species of Procellariiform, Bryan's Shearwater (Puffinus bryani), was described by Pyle, A. J. Welch, and R. C. Fleischer in 2011 based on a specimen collected by Amerson in February 1963 on Midway Atoll, Northwestern Hawaiian Islands. It had been misidentified as a Little Shearwater (P. assimilis) but genetically appears closer to a clade including the Newell's Shearwater (P. newelii) of the Southeastern Hawaiian Islands. During the winters of 1990-1991 and 1991-1992, a second Bryan's Shearwater was discovered calling in a rock crevice near the northeast corner of Sand Island, Midway, and photographed, videotaped, and audiotaped by David and Eilerts in December 1991. These two records likely represented prospecting individuals, and the locations of source colonies of Bryan's Shearwaters remain unknown. There have also been several reports of Little Shearwaters in the North Pacific that may or may not have represented mis-identified Bryan's Shearwaters. Here we present updated information on seasonality, breeding habitat requirements, and vocalizations of Bryan's Shearwaters based on the 1963 and 1991 records, and we review potential at-sea records in the North Pacific. Bryan's Shearwaters are undoubtedly rare and, if extant, may need targeted conservation actions to increase their population size. We present ideas on the potential breeding and foraging ranges, breeding habitat, and next conservation steps to protect this newly discovered seabird.