Océanite de Swinhoe

Identification

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.<p>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 Hydrobates 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.

Taxonomie

Nom scientifique

Hydrobates monorhis

Autorité

(Swinhoe, 1867)

Ordre

Procellariiformes

Famille

Hydrobatidés

Genre

Hydrobates

Répartition et habitat

It breeds on islands in the northwest Pacific off the Russian Far East, 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.<p>It breeds on Verkhovsky Island (7,500 pairs), south of Vladivostok, Russia, and Japan (a minimum of 1,000 pairs). There are little-known populations in China, Taiwan, North Korea and South Korea, and records suggest that breeding may also occur in the North Atlantic. In winter, it migrates south and west to the northern Indian Ocean (Brooke 2004). Sato et al. (2010) also estimate the world population at a minimum of 130,000 pairs, confirming that the species has a very large population. However, Birds Korea (2010) state that c. 100,000 pairs nest on Gugeul Islet, implying that possibly over 75% of the global population breed on one very small island. The species nests at six or seven breeding islets in South Korea (Chang-Yong Choi in litt. 2012). There is apparently anecdotal evidence that some colonies are in decline (N. Moores in litt. 2011).

Aire de reproduction

IO, PO : Verkhovsky and Karamzhin is. and satellite islets (sw of Vladivostok, Russia), off Honshu, Shikoku and Kyushu (c Japan), Korean Pen., off Shandong and Guangdong (e China) and Taiwan; possibly also Macaronesia (off nw Africa)

Aire hors reproduction

through seas of e Indonesian Arch., Ashmore Reef (nw of Australia) to w, s India and Sri Lanka, Arabian Sea, and off ne African coast, mostly n of Equator

Migration

Complete migrants

Conservation

Tendance de la population

stable