Matsudaira's Storm-Petrel Hydrobates matsudairae Scientific name definitions

24–25 cm; 62 g (1 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ); wingspan 46–56 cm (2 Safford, R. J., and A. F. A. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ). Large dark storm-petrel with long forked tail  , long wings , and noticeable white shafts at base of primaries forming distinct mark on upperwing. Head, body and most of wing-coverts dark sooty-brown, often more blackish over head and neck  , blackest on tail  and especially on remiges and upper primary-coverts, with large and sometimes contrasting pale panel  , usually diffuse towards forewing, formed by browner or buffier tinge to inner, central and bases of outer greater coverts, central and outer median coverts and outer lesser coverts, this panel reaching bend of wing and larger towards rear base of wing by pale fringes on innermost secondaries; blackish distal upperwing has usually bold, white, crescent-shaped mark starting at leading edge and formed by basal shafts of outer 6–7 primaries  (but this feature is occasionally lacking during non-breeding season) (3 Force, M. (1997). Comments on ‘The Chalice petrel’. British Birds 90(8):339–342. Close ); iris dark brown; bill black; legs and feet black. Sexes alike, but female has marginally longer wings and tarsi than male on average (1 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ). Juvenile as adult. Some other dark storm-petrels may show some white shafts at base of primaries, but usually much more conspicuous in present species; identified also by proportions, often has neckless appearance contrasting with noticeably long tail  , thus wings seem set far forward on body; H. monorhis often has noticeable white primary shafts as well, but is smaller, with smaller head, shorter tail that is notched rather than clearly forked, and narrower wings, with upperwing panel sometimes narrower as well.

Tropical Indian Ocean and Timor Sea, breeding at Kita-Iwojima and Minami-Iwojima, in Volcano Is (Iwo Is), SE of Japan. Has also been recorded around the Ogasawara Is and is assumed by some to breed there (4 Brazil, M. (2009). Field Guide to the Birds of East Asia: Eastern China, Taiwan, Korea, Japan and Eastern Russia. Christopher Helm, London, UK. Close ), but this requires confirmation.

Marine and pelagic, normally occurring far from coast; on migration often found over waters of continental shelf; frequently occurs in warm waters, but may be associated with local areas of upwelling and convergence. Breeds on high ground on offshore islands.

Long-distance migrant: after breeding (departing Jun) (1 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), moves S across equator perhaps to Timor Sea off NW Australia, where turns W into Indian Ocean, wintering mostly in rich waters of equatorial belt around Seychelles (5 Shirihai, H. and Skerrett, A. (2016). Observations of Matsudaira’s, Wilson’s and Black-bellied Storm-petrels in Seychelles. British Birds. 109(4): 220–230. Close ) and W to Kenya (inshore records in Jul and Aug 1981) (6 Lewis, A. D., and D. E. Pomeroy (1989). A Bird Atlas of Kenya. A. A. Balkema, Rotterdam, the Netherlands. Close ), occasionally S to Malagasy region (2 Safford, R. J., and A. F. A. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ), Mozambique (Aug 2015) (7 Demey, R. (2016). Recent reports. Bulletin of the African Bird Club 23:104–123. Close ) and South Africa (Jul 1988, Mar 2002) (1 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close , 8 Flood, R. L. (2009). ‘All-dark’ Oceanodroma storm-petrels in the Atlantic and neighbouring seas. British Birds 102(7):365–385. Close ), as well as N to Chagos Is and Lakshadweep (11º N) (9 Praveen, J., R. Jayapal, and A. Pittie (2013). Notes on Indian rarities–1: Seabirds. Indian Birds 8(5):113–125. Close ), with single record off Oman, in Aug 2013 (10 Harrison, I. (2015). From the rarities committees. Sandgrouse 37(2):203–210. Close ); some perhaps winter off NE New Guinea (although no definite records from there) and others (presumably first-year birds) apparently remain all year in NE Indian Ocean (e.g. Jun record at 03º N, 88º E) (11 van den Berg, A.B., Smenk, C., Bosman, C.A.W., Haase, B.J.M., van den Niet, A.M. and Cadee, G.C. (1991). Barau’s Petrels Pterodroma baraui, Jouanin’s Petrels Bulweria fallax and other seabirds in the northern Indian Ocean in June-July 1984 and 1985. Ardea 79(1):1–14. Close , 1 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ). Exodus from Indian Ocean commences Sept and continues until Nov (2 Safford, R. J., and A. F. A. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ). Recorded (presumably on passage) through Indonesia in Mar (12 Mason, V. (2011). A revised checklist for the birds of Bali, with notes on recent additions to the avifauna. Kukila 15:1–30. Close ), May (Lombok Strait) (13 Johnstone, R.E., van Balen, S. and Dekker, R.W.R.J. (1993). New bird records for the island of Lombok. Kukila. 6(2): 124–127. Close ), Jun (Banda Sea, off Wetar) (14 Bishop, K. D. (1992). New and interesting records of birds in Wallacea. Kukila 6(1):8–34. Close ) and Sept (Lombok Strait) (15 Grantham, M. (2000). Matsudaira’s Storm Petrel second record for the Lombok Strait. Kukila. 11: 138–139. Close ), while further N there are several records off Taiwan (16 Brazil, M. (2009). Field Guide to the Birds of East Asia: Eastern China, Taiwan, Korea, Japan and Eastern Russia. Christopher Helm, London, UK. Close ). In Melanesia, recorded off New Ireland, Buka I and Bougainville (Jul–Aug) (17 Shirihai, H. (2008). Rediscovery of Beck’s Petrel Pseudobulweria becki, and other observations of tubenoses from the Bismarck archipelago, Papua New Guinea. Bull. Brit. Orn. Club 128(1):3–16. Close ) and Emira I (late Jun) (18 Tarburton, M. (2009). New birds and other interesting sightings from Melanesia. Muruk 9(2):56–91. Close ). Surprisingly few records in Japan N of breeding islands (19 Brazil, M. (1991). The Birds of Japan. Christopher Helm, London, UK. Close ).

Little information available on diet; known to feed on galley waste from ships. Feeds mainly on wing, by dipping and snatching from surface. Sometimes follows ships. Usually encountered alone or in twos during non-breeding season (2 Safford, R. J., and A. F. A. Hawkins, Editors (2013). The Birds of Africa. Volume 8. The Malagasy Region. Christopher Helm, London, UK. Close ).

No data (1 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ).

Arrives at colonies in Jan, with egg-laying from mid Mar to late Apr, and fledging from early to mid Jun (19 Brazil, M. (1991). The Birds of Japan. Christopher Helm, London, UK. Close , 1 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ). Colonial; nests in burrows. Fledging occurs mostly in Jun.

VULNERABLE. Little known, reported to breed on Kita iwojima and Minami iwojima in Volcano Is, to SE of Japan; Kita iwojima not visited recently. No population figures available (20 Baker, G. B., R. Gales, S. Hamilton, and V. Wilkinson (2002). Albatrosses and petrels in Australia: a review of their conservation and management. Emu 102(1):71–97. Close ), but speculated to be in excess of 20,000 birds (1 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ). Re-assessed as Vulnerable in 2014, due to tiny breeding range on just two islands, which makes it susceptible to stochastic events. Survey work urgently required to accurately determine population size, trends and main threats.