Swinhoe's storm petrel
|Swinhoe's storm petrel|
Thalassidroma monorhis Swinhoe, 1867
It breeds on islands in the northwest Pacific off China, Japan and Korea. It nests in colonies close to the sea in rock crevices and lays a single white egg. It spends the rest of the year at sea, ranging into the Indian Ocean and Arabian Sea.
Swinhoe's storm petrel is a small bird, 18–21 cm in length with a 45–48 cm wingspan, though distinctly larger than the European storm petrel. It is essentially dark brown in all plumages, and has a fluttering flight, pattering on the water surface as it picks planktonic food items from the ocean surface. Unlike the European storm petrel, it does not follow ships.
In structure it most resembles a Leach's storm petrel with its forked tail, longish wings, and flight behaviour, but does not have a white rump and the call differs. It is difficult to distinguish from other all-dark Oceanodroma species, and the first English record had to be DNA-tested to eliminate the possibility that it was a Leach's storm petrel, since populations of north-eastern Pacific Leach's storm petrels contain individuals that show completely dark rumps.
Habits and observation
This storm petrel is strictly nocturnal at the breeding sites to avoid predation by gulls and skuas, and will even avoid coming to land on clear moonlit nights. Like most petrels, its walking ability is limited to a short shuffle to the burrow. It is strictly pelagic outside the breeding season, and this, together with its remote breeding sites, makes Swinhoe's petrel a difficult bird to see from land. Only in storms might this species be pushed into headlands, but even then an out of range bird would probably defy definite identification.
North Atlantic status
On 8 July 1983, a bird was trapped on the Selvagens, Madeira and was confirmed to be the first record for the Atlantic Ocean. Since then a number of storm petrels exhibiting plumage and structural characteristics have been recorded at sea, principally in the North Atlantic, while birds were trapped during the summer months in France (1989), England (1989 (two birds), 1990 (with birds retrapped from 1991 to 1994)), Spain (1994), Norway (1996, 1997), and again Madeira (1991, 1994). Other than the east North Atlantic and the Mediterranean Sea a number of other individuals have been identified in the western North Atlantic. Records of single birds off Hatteras, North Carolina, on 20 August 1993, on 8 August 1998, and 2 June 2008 have all been accepted as valid North American records.
- BirdLife International (2012). "Oceanodroma monorhis". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- Beolens, Bo; Watkins, Michael (2003). Whose Bird? Men and Women Commemorated in the Common Names of Birds. London: Christopher Helm. pp. 331–332.
- "Recently recategorised species". Birdlife International (2012). Retrieved 15 June 2012.
- James, P.C., & Robertson, H.A. 1985. First record of Swinhoe's Storm Petrel Oceanodroma monorhis in the Atlantic Ocean. Ardea 73: 105-106.
- Morrison, S. 1998. All-dark petrels in the North Atlantic. British Birds 91: 540-560
- American Ornithologists' Union (AOU) (2000): Forty-second supplement to the American Ornithologists' Union Check-list of North American Birds. Auk 117(3): 847–858. DOI: 10.1642/0004-8038(2000)117[0847:FSSTTA]2.0.CO;2