First record of the greater shearwater (Puffinus gravis) in Alaska

First Record of a Greater Shearwater (Puffinus gravis) in Alaska

JOHN M. PEARCE
Alaska Science Center, U.S. Geological Survey, 1011 E. Tudor Road, Anchorage, Alaska 99503

Photo by John M. Pearce

The Greater Shearwater (Puffinus gravis) breeds in the Southern Atlantic Ocean with post-breeding dispersal to the North Atlantic. On 3 August 2001, I observed and photographed an unidentified shearwater (see photo) in the Gulf of Alaska, about 30 kilometers off the southern coast of Montague Island (59˚50’ N, 148˚ 00’ W). The bird was subsequently identified as a Greater Shearwater. This observation and photographic documentation provided the first Alaska state record (D. Gibson, in litt.) and one of very few records for the North Pacific. This is the 464^th bird species to be recorded in the state of Alaska.

At the time of the sighting, several Fork-tailed Storm Petrels (Oceanodroma furcata) and Northern Fulmars (Fulmaris glacialis) were near our boat, while Sooty Shearwaters (P. griseus) and/or Short-tailed Shearwaters (P. tenuirostris) were seen in the distance. The unknown shearwater flew in, landed 50 feet away, and quickly swam to within 20 feet of the boat. It dove and swam underwater to forage using its wings for propulsion, a common behavior among shearwaters (Burger 2001). At times, the shearwater swam directly under the boat.

The photo clearly shows the bird to be a Greater Shearwater, a species that averages slightly larger than the Northern Fulmar (also shown). All other shearwater species with similar markings are smaller than Northern Fulmars. The bird was reminiscent of a Parasitic Jaeger (Stercorarius parasiticus) with a dark cap that extends below the eye and becomes faint over the nape, giving way to a nearly white neck and throat. The shearwater also has mottled, light brown flanks, and buffy sides. The photo also shows the birds brown wings with paler edging, dark undertail coverts, and a long, thin, blackish bill.

Greater Shearwaters have been reported five times off the Pacific coast of California and once off extreme southern Chile (Harrison 1983). No records are known from pelagic surveys conducted on the high seas of the Pacific (A. Jaramillo, pers. comm.). The latitude of the Alaska observation (60˚N) is not atypical for a Greater Shearwater in early August. Nearly all of the world’s Greater Shearwaters spend the austral winter in the North Atlantic between 45˚ and 51˚ N latitude (del Hoyo 1992, Huettman and Diamond 2000) after dispersing from South Atlantic breeding colonies on the islands of Tristan da Cunha. Small numbers of nesting birds (< 15 pairs) have also been observed on Kidney Island in the Falklands since the 1960s (Woods 1988), and Watson (1971) suggested that an undiscovered breeding colony may exist in the Tierra del Fuego area due to the presence of molting birds there.

Thanks to my lovely wife Elizabeth and her father Whip Manning for the memorable boat ride. T. Van Pelt, J. Piatt, R. Gill Jr., T. Tobish, N. Senner, D. Gibson, and D. Christian assisted with identification of the bird as P. gravis. R. Gill Jr., T. Tobish, D. Derksen, N. Senner, D. Ruthrauff, T. Van Pelt, and R. Hamilton provided editorial assistance.

LITERATURE CITED

Burger, A. E. 2001. Diving depths of shearwaters. Auk 118:755–759.

del Hoyo, J., Elliott, A., and Sargatal, J. (eds.). 1992. Handbook of Birds of the World, vol.1. Lynx Edicions, Barcelona, Spain.

Erickson, R. A., and Terrill, S. B. 1996. Nineteenth report of the California Bird Records Committee: 1993 records. Western Birds 27:93–126.

Harrison, P. 1983. Seabirds, an identification guide. Houghton Mifflin Co., Boston.

Howell, S. N. G., and Pyle, P. 1997. Twentieth report of the California Bird Records Committee: 1994 records. Western Birds 28:117–141.

Huettman, F., and Diamond, A. W. 2000. Seabird migration in the Canadian northwest Atlantic Ocean: moulting locations and movement patterns of immature birds. Canadian Journal of Zoology 78:624–647.

McCaskie, G., and San Miguel, M. 1999. Report of the California Bird Records Committee: 1996 records. Western Birds 30:57–85.

Watson, G. E. 1971. Molting Greater Shearwaters (Puffinus gravis) off Tierra del Fuego. Auk 88:440–442.

Woods, R. 1988. Guide to the birds of the Falkland Islands. Anthony Nelson, Ltd., Shropshire, England.