Streaked Shearwater Calonectris leucomelas Scientific name definitions

In many ways the East Asian counterpart of the European-distributed Cory’s Shearwater (Calonectris borealis) complex, the Streaked Shearwater breeds in northeast Japan, and on the Izu Islands and Ryukyu Islands, as well as on islands off the Russian Far East, eastern China and the Korean Peninsula. In the non-breeding season at-sea dispersal is extensive, although a comparatively small percentage of the well in excess of one million-strong population remain in Japanese waters at this time, most migrate south towards Australia and large flocks occur off New Guinea, with the southernmost record in New Zealand, while some move east to Hawaii and and the Pacific coast of the United States, as well as west into the Indian Ocean, where it has reached as far afield as South Africa and the head of the Red Sea at Eilat, in southern Israel. The latter records, in the early 1990s, permitted the observers to practice separating this species from the much more regular Cory’s Shearwater, versus which it differs in having a more wedge-shaped tail, and especially by its pale face, contrasting dark nape, and relatively slenderer bill.

Large, distinctive, brownish shearwater with mostly clean white underparts, mottled head (due to variable white spots and streaks on face and crown), and rather large, pale bill, with variable dark streaks on the underside of the primary-coverts.

Recalls Cory's Shearwater (<em>C. diomedea</em>) in size, flight action and upperparts colour, usually less so on underwing , but separated by more wedge-shaped tail, and especially by pale face and contrasting dark nape, while bill is relatively slender, similar to that of Cape Verde Shearwater (C. edwardsii). Same features distinguish it from large Pterodroma. From other shearwaters by pale face and bill, and by lazy flight on rather bowed wings.

Juvenile

As adult.

Adult

Head variably mottled white and blackish brown, the white usually predominating around eye, on forehead and foreface, the dark markings being larger and more solidly dark on nape, rest of upperparts gray-brown, pale feather fringes affording scaly appearance to mantle, scapulars, rump and uppertail-coverts, the latter often with obvious white tips that can look like narrow white horseshoe. Most of upperwing slightly darker brown, darkest on primary-coverts and remiges, tertials and lowermost scapulars also dark, often giving upperparts diffuse dark M pattern. Uppertail blackish brown; underwing is dark grey on exposed remiges forming dark trailing edge much broader at wingtip, otherwise white except dark spot on some of outer greater primary-coverts, median primary-coverts usually have mostly dark outer webs forming broken dark crescent on centre of outer wing, narrow dark streaks on leading edge in carpal region and on lesser coverts forming weak dark diagonal band on underwing, but dark markings variable and some birds have nearly all-white underwing-coverts. Sides of neck to sides of chest brownish with blurry pale scaling, rest of underparts white. Sexes alike in plumage, although males have significantly deeper and longer bills, longer heads, longer tarsi, greater wingspans and greater wing areas than females, but overall wing and tail lengths, and aspect ratios do not differ between sexes, while the species shows greater degree of sexual dimorphism in bill size than other Calonectris species (1 Shirai, M., Niizuma, Y., Tsuchiya, K., Yamamoto, M. and Oka, N. (2013). Sexual size dimorphism in Streaked Shearwaters Calonectris leucomelas. Ornithological Science 12(1):57–62. Close ).

Poorly known. Adults are probably molting their wing feathers mainly between November and March; and first-years between September and January (2 Howell, S. N. G., and K. Zufelt (2019). Oceanic Birds of the World. Princeton University Press, Princeton, NJ, USA. Close ).

Bill

Pale horn to grey, with some dusky gray separating the tip from the rest of the bill (often looks dark-tipped in field) (3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ).

Iris

Blackish brown (3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ).

Legs and Feet

Pink, but can have dusky-gray outer toes (3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ).

Linear Measurements

Overall length 45–52 cm (4 Howell, S. N. G. (2012). Petrels, Albatrosses, and Storm-Petrels of North America: A Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close ).

Linear measurements (in mm, with means, standard deviation, and sample sizes in parentheses, taken during the incubation or chick-rearing period at eight breeding colonies in Japan, most of them around Honshu 5 Yamamoto, T., Kohno, H., Mizutani, A., Yoda, K., Matsumoto, S., Kawabe, R., Watanabe, S., Oka, N., Sato, K., Yamamoto, M., Sugawa, H., Karino, K., Shiomi, K., Yonehara, Y. and Takahashi, A. (2016). Geographical variation in body size of a pelagic seabird, the streaked shearwater Calonectris leucomelas. Journal of Biogeography 43(4):801–808. Close ):

Mass

348–710 g (5 Yamamoto, T., Kohno, H., Mizutani, A., Yoda, K., Matsumoto, S., Kawabe, R., Watanabe, S., Oka, N., Sato, K., Yamamoto, M., Sugawa, H., Karino, K., Shiomi, K., Yonehara, Y. and Takahashi, A. (2016). Geographical variation in body size of a pelagic seabird, the streaked shearwater Calonectris leucomelas. Journal of Biogeography 43(4):801–808. Close ).

Wingspan

103–113 cm (4 Howell, S. N. G. (2012). Petrels, Albatrosses, and Storm-Petrels of North America: A Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close ).

Sometimes placed in the genus Procellaria, or in Puffinus (6 Peters, J. L. (1931). Check-list of Birds of the World. Volume 1. Harvard University Press, Cambridge, MA, USA. Close ).

None.

Monotypic.

Western Pacific Ocean and east Indian Ocean, breeding in northeast Japan, on the Izu Islands and Ryukyu Islands to the Pescadores Islands (off western Taiwan); also on islands off the southeast Russian Far East (3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), eastern China and Korea.

Marine and partly pelagic, also occurring over inshore waters (7 Brazil, M. (1991). The Birds of Japan. Christopher Helm, London, UK. Close ). Typically breeds on offshore islands, occupying forested hills, e.g. of Machilus thunbergii (8 Maesako, Y. (1985). Community structure of Machilus thunbergii forests disturbed by birds (Streaked Shearwater) on Kanmurijima Island, Kyoto Prefecture, Japan. Japanese Journal of Ecology 35:387–400. Close ).

During breeding season is generally concentrated in seas around Japan and off Korea, but overall range at this period extends east to c. 160°E (3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ) and south to the northern Philippines at 19°N (9 Dickinson, E. C., R. S. Kennedy, and K. C. Parkes (1991). The Birds of the Philippines. An Annotated Checklist. B.O.U. Check-list 12. British Ornithologists’ Union, Tring, UK. Close ,10 Nakagun, S., Layusa, C.A.A. and Acebes, J.M.V. (2016). Seabird fauna of the Babuyan Channel and adjacent waters, northern Luzon, Philippines. Marine Ornithology 44(1):43–49. Close ). During incubation period, shearwaters breeding on the islands of Sangan and Mikura, in the northwest Pacific, foraged in the Kuroshio-Oyashio transition area, while those nesting on Awa Island mostly foraged in the Sea of Japan; although those from Mikura Island foraged in the northwest Pacific, the distance between their colony and foraging areas was greater (mean 645 km; range 546–756 km), compared to birds on Sangan (272 km; range 244–297 km) and Awa (228 km; range 75–518 km) (11 Yamamoto, T., Takahashi, A., Oka, N., Shirai, M., Yamamoto, M., Katsumata, N., Sato, K., Watanabe, S. and Trathan, P.N. (2012). Inter-colony differences in the incubation pattern of Streaked Shearwaters in relation to the local marine environment. Waterbirds 35(2):248–259. Close ,12 Ochi, D., Matsumoto, K., Oka, N., Deguchi, T., Sato, K., P. Satoh, T.P., Muto, F. and Watanuki, Y. (2016). Dual foraging strategy and chick growth of Streaked Shearwater Calonectris leucomelas at two colonies in different oceanographic environments. Ornithological Science 15(2):213–225. Close ). Those nesting on Awashima Island in the Sea of Japan move into the Pacific Ocean, via the Tsugaru Strait, to feed, perhaps especially in years when waters around the breeding grounds are warmer, but males appear to do more than females, apparently because their greater wing loadings creates higher energy demands that necessitate visiting better foraging areas (13 Matsumoto, S., Yamamoto, T., Yamamoto, M., Zavalaga, C.B. and Yoda, K. (2017). Sex-related differences in the foraging movement of Streaked Shearwaters Calonectris leucomelas breeding on Awashima Island in the Sea of Japan. Ornithological Science 16(1):23–32. Close ). Small numbers remain in Japanese waters during winter (7 Brazil, M. (1991). The Birds of Japan. Christopher Helm, London, UK. Close ), but most migrate south towards Australia between November and April (14 Melville, D.S. (1984). Seabirds of China and the surrounding seas. Pp. 501–511 in: Croxall et al. (1984). Close ,15 Marchant, S., and P. J. Higgins, Editors (1990). Handbook of Australian, New Zealand & Antarctic birds. Volume 1. Ratites to ducks. Part A. Ratites to petrels. Oxford University Press, Melbourne, Australia. Close ,3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ): there are many ringing returns from Philippines; large flocks occur off New Guinea (16 Coates, B. J. (1985). The Birds of Papua New Guinea. Volume 1. Non Passerines. Dove Publications, Alderley, Queensland, Australia. Close ,17 Wardill, J.C. and Nando, T. (2000). Concentrations of wintering Streaked Shearwaters off the northern coast of West Papua. Kukila 11:151. Close ,18 Tarburton, M. (2009). New birds and other interesting sightings from Melanesia. Muruk 9(2):56–91. Close ,19 Beehler, B. M., and T. K. Pratt (2016). Birds of New Guinea: Distribution, Taxonomy, and Systematics. Princeton University Press, Princeton, NJ, USA. Close ) and the species is regular elsewhere in Indonesian waters (3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close , 20 Wardill, J.C., Nando, T. and Amanta, F.P. (2000). A passage of Streaked Shearwaters past the Talaud Islands, North Sulawesi. Kukila 11:149–150. Close ,21 Johnstone, R. E., and S. (B.) van Balen (2013). The birds of the Kai and Tayandu Islands, Maluku region, Indonesia. Western Australian Naturalist 29(1):11–56. Close ), where mainly recorded from September, but also as early as May–June (22 Bishop, K. D. (1992). New and interesting records of birds in Wallacea. Kukila 6(1):8–34. Close , 23 Mason, V. (2011). A revised checklist for the birds of Bali, with notes on recent additions to the avifauna. Kukila 15:1–30. Close ); now known to be regular off northern Australia, with some moving along the west and east coasts to southern Australia, e.g. off New South Wales (24 Carter, M. (1983). The Streaked Shearwater as an Australian bird. Royal Australian Ornithologists' Union Newsletter 56:5–6. Close ,3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ); and recently recorded (February 2006) as far southeast as New Zealand (25 Gill, B. J., B. D. Bell, G. K. Chambers, D. G. Medway, R. L. Palma, R. P. Scofield, A. J. D. Tennyson, and T. H. Worthy (2010). Checklist of the Birds of New Zealand, Norfolk and Macquarie Islands, and the Ross Dependency, Antarctica. 4th edition. Ornithological Society of New Zealand & Te Papa Press, Wellington, New Zealand. Close ,26 Scofield, R.P., Christie D., Palma R.L., and Tennyson A.J.D. (2010). First record of streaked shearwater (Calonectris leucomelas) in New Zealand. Notornis 57(4):212–215. Close ). A study using geolocators, attached to 48 breeding birds in 2006 and subsequently recovered from 38 birds the following year, confirmed that the species migrated from the seas around Japan to three wintering areas in the tropics, the seas off northern New Guinea, the Arafura Sea, and South China Sea (4,000 km, 5,400 km, and 3,500 km from their breeding colony, respectively), with most in the first-named area, in seas of low primary productivity but high skipjack tuna Katsuwonus pelamis abundance (27 Yamamoto, T., Takahashi, A., Katsumata, N., Sato, K. and Trathan, P.N. (2010). At-sea distribution and behavior of Streaked Shearwaters (Calonectris leucomelas) during the nonbreeding period. Auk 127(4):871–881. Close ). Telemetric studies have demonstrated that juveniles from a colony in northern Honshu take a different route from adults during their first southward migration, initially moving south overland, crossing the island’s mountains, whereas adults travel over water (28 Yoda, K., Yamamoto, T., Sukuki, H., Matsumoto, S., Müller, M. and Yamamoto, M. (2017) Compass orientation drives naïve pelagic seabirds to cross mountain ranges. Current Biology 27(21): R1152–R1153. Close ). Vagrants have been recorded east to Hawaii (29 Marks, J.S. (1990). Streaked Shearwater (Calonectris leucomelas) on Laysan Island: first documented record for Hawaii. 'Elepaio 50(4):31–32. Close ) and the west coast of the USA (mid August to mid October), off Oregon (30 Force, M.P., Rowlett, R.A. and Grace, G. (1999). A sight record of a Streaked Shearwater in Oregon. Western Birds 30(1):49–52. Close ) and California, with single inland records in California and Wyoming (31 Faulkner, D. (2006). A Streaked Shearwater (Calonectris leucomelas) record for Wyoming. North American Birds 60(3):324–326. Close , 4 Howell, S. N. G. (2012). Petrels, Albatrosses, and Storm-Petrels of North America: A Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close ), as well as west to southern India (32 Praveen, J., R. Jayapal, and A. Pittie (2013). Notes on Indian rarities–1: Seabirds. Indian Birds 8(5):113–125. Close ), Sri Lanka, the Maldives (33 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 ,34 Anderson, R. C., and M. Baldock (2001). New records of birds from the Maldives with notes on other species. Forktail 17:67–73. Close ) (mainly September–February, but also July, in South Asian waters) (32 Praveen, J., R. Jayapal, and A. Pittie (2013). Notes on Indian rarities–1: Seabirds. Indian Birds 8(5):113–125. Close , 35 Dipu K., Palot, M.J., Praveen J., Sreenivasan, P.P., and Uthaman, K.V. (2013). Streaked Shearwater Calonectris leucomelas from Kannur coast, Kerala. Indian Birds 8(2):44–45. Close ), South Africa (3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ) and, most exceptionally, at the head of the Red Sea at Eilat, on the Israel/Jordan border, in June to mid September 1992, and May–July 1993 (36 Morgan, J. and Shirihai, H. (1992). Streaked Shearwaters in Israel – a new Western Palearctic bird. Birding World 5(9):344–347. Close ,37 Andrews, I.J., Khoury, F. and Shirihai, H. (1999). Jordan Bird Report 1995–97. Sandgrouse 21(1):10–35. Close , 38 Shirihai, H. (1999). Fifty species new to Israel, 1979–1998: their discovery and documentation, with tips on identification. Sandgrouse 21(1):45–105. Close ), as well in Egypt in April 2015 (EORC report).

Mainly fish and squid. Birds rearing chicks on Mikura Island, Japan, made many short trips (< 2 days) and some long ones (4–10 days); during short trips, birds stayed in warmer Kuroshio and Kuroshio-Oyashio mixed water regions, and fed on Japanese anchovies (Engraulis japonicus), squid (Todarodes pacificus) and flying-fishes (Cypselurus hiraii), whereas during longer trips they visited the colder Oyashio region and fed on anchovies and Pacific saury Cololabis saira (39 Matsumoto, K., Oka, N., Ochi, D., Muto, F., Satoh, T.P. and Watanuki, Y. (2012). Foraging behavior and diet of Streaked Shearwaters Calonectris leucomelas rearing chicks on Mikura Island. Ornithological Science 11(1):9–19. Close ,12 Ochi, D., Matsumoto, K., Oka, N., Deguchi, T., Sato, K., P. Satoh, T.P., Muto, F. and Watanuki, Y. (2016). Dual foraging strategy and chick growth of Streaked Shearwater Calonectris leucomelas at two colonies in different oceanographic environments. Ornithological Science 15(2):213–225. Close ). Prey captured by surface-seizing; also makes shallow plunges (40 Kuroda, N. (1954). On the Classification and Phylogeny of the Order Tubinares, Particularly the Shearwaters (Puffinus), with Special Consideration on Their Osteology and Habit Differentiation. N. Kuroda, Tokyo, Japan. Close ). Study during chick-rearing period off Japan found that shearwaters made 50.3 landings per day (± 9·8, n = 12) and spent 44.8% (± 8, n = 12) of their time on the water (41 Shirai, M., Yamamoto, M., Ebine, N., Yamamoto, T., Trathan, P.T., Yoda, K., Oka, N. and Niizuma, Y. (2012). Basal and field metabolic rates of Streaked Shearwater during the chick-rearing period. Ornithological Science 11(1):47–55. Close ), and another study reported that birds spent 76–96% of their time at sea flying, 4–24% landing on water and completed 0.5–17 dives per day, all of them shallow (< 6 m) (39 Matsumoto, K., Oka, N., Ochi, D., Muto, F., Satoh, T.P. and Watanuki, Y. (2012). Foraging behavior and diet of Streaked Shearwaters Calonectris leucomelas rearing chicks on Mikura Island. Ornithological Science 11(1):9–19. Close ). Often associates with other seabirds, especially other Procellariiformes, e.g. Wedge-tailed Shearwater Ardenna pacifica (42 Bailey, S.F. (1992). Seabirds of Madang Province, Papua New Guinea, September–November 1989. Emu 92(4):223–232. Close ), Flesh-footed Shearwater A. carneipes (35 Dipu K., Palot, M.J., Praveen J., Sreenivasan, P.P., and Uthaman, K.V. (2013). Streaked Shearwater Calonectris leucomelas from Kannur coast, Kerala. Indian Birds 8(2):44–45. Close ) and Wilson’s Storm-petrel Oceanites oceanicus (22 Bishop, K. D. (1992). New and interesting records of birds in Wallacea. Kukila 6(1):8–34. Close ), but also in mixed-species feeding flocks containing frigatebirds (Fregata), boobies (Sula) (22 Bishop, K. D. (1992). New and interesting records of birds in Wallacea. Kukila 6(1):8–34. Close ), gulls (Larus spp.), and cormorants (Phalacrocorax spp.), among others (4 Howell, S. N. G. (2012). Petrels, Albatrosses, and Storm-Petrels of North America: A Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close ), sometimes with cetaceans such as Short-finned Pilot Whales Globicephala macrorhynchus (22 Bishop, K. D. (1992). New and interesting records of birds in Wallacea. Kukila 6(1):8–34. Close ). Follows fishing boats; is attracted to anchovy crawls off Japan, and may feed on prey driven to the surface by predatory skipjack tuna Katsuwonus pelamis (42 Bailey, S.F. (1992). Seabirds of Madang Province, Papua New Guinea, September–November 1989. Emu 92(4):223–232. Close ).

Vocal at colonies, where calls loudly and frequently both on ground and in flight, with evidence for some sexual dimorphism in vocalizations, with, for example, females uttering longer phrases (43 Bretagnolle, V., and B. Lequette (1990). Structural variation in the call of Cory's Shearwater (Calonectris diomedea, Aves, Procellariidae). Ethology 85:313–323. Close ,44 Warham, J. (1996). The Behaviour, Population Biology, and Physiology of the Petrels. Academic Press, San Diego, CA, USA. Close ,3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ) and lower-pitched calls (45 Arima, H., Oka, N., Baba, Y., Sugawa, H. and Ota, T. (2014). Gender identification by calls and body size of the Streaked Shearwater examined by CHO genes. Ornithological Science 13(1):9–17. Close ).

Starts March and ends in November, with pre-laying exodus of 13–17 days (females) or 4–7 days (males) (11 Yamamoto, T., Takahashi, A., Oka, N., Shirai, M., Yamamoto, M., Katsumata, N., Sato, K., Watanabe, S. and Trathan, P.N. (2012). Inter-colony differences in the incubation pattern of Streaked Shearwaters in relation to the local marine environment. Waterbirds 35(2):248–259. Close ), egg-laying commences in May and peaks in mid to late June (but sometimes does not start until July) (11 Yamamoto, T., Takahashi, A., Oka, N., Shirai, M., Yamamoto, M., Katsumata, N., Sato, K., Watanabe, S. and Trathan, P.N. (2012). Inter-colony differences in the incubation pattern of Streaked Shearwaters in relation to the local marine environment. Waterbirds 35(2):248–259. Close ), hatching generally peaks between 10 and 20 August, fledging from Octpber and departure continues through November, stragglers remaining into December (3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ). Strictly nocturnal at colonies (3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), but presence there does not seem unduly influenced by ambient moonlight levels (46 Van Tatenhove, A., Fayet, A., Watanuki, Y., Yoda, K. and Shoji, A. (2018). Streaked Shearwater Calonectris leucomelas moonlight avoidance in response to low aerial predation pressure, and effects of wind speed and direction on colony attendance. Marine Ornithology 46(2):177–185. Close ). Long-term study (1984–2010) on Kanmurijima Island, in the Sea of Japan, based on band recoveries, indicated high levels of site fidelity and natal philopatry; even after 20 years, birds returned to the vicinity of the initial release site and only very small percentages (0.7% and 0.2%) of returns were at other study sites (even then were on the same island) (47 Sugawa, H., Karino, K., Ohshiro, A. and Hirai, M. (2014). Long-term trends in breeding site fidelity of Streaked Shearwater Calonectris leucomelas. Marine Ornithology 42(1):11–15. Close ). Long-term monogamous, but recent study reported that extra-pair males sired 15% of 113 offspring during a study in 2014–2016, which percentage is among the highest recorded rates of extra-pair paternity among seabirds (48 Sakao, M., Takeshima, H., Inoue, K. and Sato, K. (2019). Extra‑pair paternity in socially monogamous Streaked Shearwaters: forced copulation or female solicitation? Journal of Ornithology 160(1):137–144. Close ). Colonial; nests in burrows . Single white egg; incubation c. 45–64 days in five to six shifts (3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close , 11 Yamamoto, T., Takahashi, A., Oka, N., Shirai, M., Yamamoto, M., Katsumata, N., Sato, K., Watanabe, S. and Trathan, P.N. (2012). Inter-colony differences in the incubation pattern of Streaked Shearwaters in relation to the local marine environment. Waterbirds 35(2):248–259. Close ); fledging period c. 66–87 days (49 Yoda, K., Shiozaki, T., Shirai, M., Matsumoto, S. and Yamamoto, M. (2017). Preparation for flight: pre-fledging exercise time is correlated with growth and fledging age in burrow-nesting seabirds. Journal of Avian Biology 48(6):881–886. Close ). In Japan, duration of incubation shifts show significant inter-colony differences, but no sex-related differences; those on Sangan Island had shorter mean incubation shifts (5.6 days on average; range 3–8 days) than those on Mikura Island (7.2 days; range 4.8–10.7 days) and Awa Island (6.9 days; range 6.0–9.7 days) (11 Yamamoto, T., Takahashi, A., Oka, N., Shirai, M., Yamamoto, M., Katsumata, N., Sato, K., Watanabe, S. and Trathan, P.N. (2012). Inter-colony differences in the incubation pattern of Streaked Shearwaters in relation to the local marine environment. Waterbirds 35(2):248–259. Close ). Factors affecting breeding success are poorly known, but predators include feral cats (Felis catus) (49 Yoda, K., Shiozaki, T., Shirai, M., Matsumoto, S. and Yamamoto, M. (2017). Preparation for flight: pre-fledging exercise time is correlated with growth and fledging age in burrow-nesting seabirds. Journal of Avian Biology 48(6):881–886. Close ). No further information (50 Yoshida, N. (1962). [Breeding ecology of the Streaked Shearwater at Kammurijima I., Maizuru in Kyoto.] Tori 17:83–108. (In Japanese.) Close ,51 Yoshida, N. (1981). [Seabirds that Climb Trees.] Ubunsha, Tokyo. (In Japanese.) Close ,52 Jida, N., Maruyama, N., Oka, N. and Kuroda, N. (1987). [Structure of a colony of Streaked Shearwaters on Mikura Island]. Journal of the Yamashina Institute of Ornithology 19:56–76. (In Japanese.) Close ,3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ).

Not globally threatened. Currently considered Near Threatened. Abundant and widespread, with total population of several million birds; well in excess of 1,000,000 pairs in Japan (7 Brazil, M. (1991). The Birds of Japan. Christopher Helm, London, UK. Close ), of which largest concentration is in northern Izu Islands, most significantly 1,750,000–3,500,000 birds breeding on Mikura-jima (53 Hasegawa, H. (1984). Status and conservation of seabirds in Japan, with special attention to the Short-tailed Albatross. In Status and Conservation of the World’s Seabirds (J. P. Croxall, P. G. H. Evans, and R. W. Schreiber, Editors), ICBP Technical Publications, International Council for Bird Preservation, Cambridge, UK. pp. 487–500 Close ), with fewer than 150 pairs in the Russian Far East, on Karamzin Island (54 Litvinenko, N., and Y. Shibaev (1991). Status and conservation of the seabirds nesting in southeast U.S.S.R. In Seabird Status and Conservation (J. P. Croxall, Editor), International Council for Bird Preservation, Cambridge, UK. pp. 175–204. Close ), while unknown numbers breed on islets off the Korea Peninsula, although recent surveys have demonstrated the existence of 19 confirmed colonies (one numbering almost 21,000 pairs) and four additional islands may also support nesting birds, and the species has probably been extirpated on three others (55 Hart, K.A., Choi, C.-Y., Bond, A.L., Humphries, G.R.W., Yoo, J.-C. and Nam, K.-B. (2015). Streaked Shearwaters Calonectris leucomelas of the Korean Peninsula: distribution, status and potential threats. Forktail 31:55–63. Close ). Human exploitation accounts for large numbers throughout the range (as many as 30,000 chicks used to be taken annually on Mikura-jima) (3 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), despite some protective laws; on many islands exploitation is traditional. Many birds die entangled in fishing nets; and there is some predation by feral cats (Felis catus) and rats (Rattus spp.). Mikura-jima islanders report that the population there is declining rapidly, probably due to predation by both rats and cats, but quantitative data are lacking (BirdLife International 2016), while potential predators present on some Korean nesting islands include rats (both Rattus rattus and R. norvegicus), cats, dogs and Siberian Weasals Mustela sibirica (55 Hart, K.A., Choi, C.-Y., Bond, A.L., Humphries, G.R.W., Yoo, J.-C. and Nam, K.-B. (2015). Streaked Shearwaters Calonectris leucomelas of the Korean Peninsula: distribution, status and potential threats. Forktail 31:55–63. Close ). Oil spills may also affect the species in Korean waters, although evidence for this is currently lacking (55 Hart, K.A., Choi, C.-Y., Bond, A.L., Humphries, G.R.W., Yoo, J.-C. and Nam, K.-B. (2015). Streaked Shearwaters Calonectris leucomelas of the Korean Peninsula: distribution, status and potential threats. Forktail 31:55–63. Close ). Significantly reduced levels of vitamin A have been found in nestlings on Mikura-jima, which has been linked to the fact that throughout incubation, and possibly also during the period when nestlings are fed, the majority of the global population forages in a marine area affected by fallout from the 2011 Fukushima nuclear plume (56 Uematsu, S., Uematsu, K., Lavers, J.L., and Congdon, B.C. (2014). Reduced vitamin A (retinol) levels indicate radionuclide exposure in Streaked Shearwaters (Calonectris leucomelas) following the 2011 Fukushima nuclear accident. Ecological Indicators 43:244–251. Close ). Protective measures are required, e.g. effective legal protection of species, combined with programmes of environmental education; fishing activities could be made less harmful to birds with suitable regulations concerning areas, seasons, methods and gear. Cats are being neutered and released on Mikura-jima (BirdLife International 2016). Not considered of conservation concern until 2015, when fears over possible population declines led to its listing as Near Threatened.