IDENTIFICATION

38-47 cm. Compared to other similar-sized shearwaters and petrels the broad-based wings are usually bowed and held forward while the tail is long, broad and wedge-shaped. Most birds in the north Pacific are light morphs (including all birds at Japanese colonies), which have dark brown upperparts with a whitish underbody, and on the underwing dark grey flight feathers, whitish coverts and a dark leading edge. The dark morph is also dark brown above, darkest on the primaries, but may show a weak M on upper wing, and has underparts slightly paler, especially the chin and throat. Thus far, birds recorded in HK have been dark morph.

VOCALISATIONS

Non-breeding birds not known to call in flight.

DISTRIBUTION & HABITAT PREFERENCE

Both records have occurred over the sea, one during a tropical storm.

OCCURRENCE

2001: one off Cape D’Aguilar on 6 July during close passage of a tropical storm (Leader 2009).

2008: one in eastern waters on 27 September.

BEHAVIOUR, FORAGING & DIET

No observations.

RANGE & SYSTEMATICS

Monotypic. Breeds on islands in tropical and subtropical areas of Indian and Pacific Oceans from Madagascar to northwest Australia and Japan to east Australia east to Mexico, though most sites are in the western Pacific (Whittow 2020). In China a vagrant to Shanghai, Jiangsu, Taiwan and Hainan (Liu and Chen 2020).

CONSERVATION STATUS

IUCN: Least Concern. Population trend decreasing.