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Swinhoe's Storm-petrel Oceanodroma monorhis

This species has been uplisted to Near Threatened on the basis that its population is expected to undergo a moderately rapid decline over the next three generations owing to the impacts of introduced species and human activities, such as mining and tourism.

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: _the_WP15.xls.
Brooke, M. De L. 2004. Albatrosses and petrels across the world. Oxford University Press, Oxford.
Christidis, L.; Boles, W. E. 2008. Systematics and taxonomy of Australian birds. CSIRO Publishing, Collingwood, Australia.
Cramp, S.; Perrins, C. M. 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
Dowsett, R. J.; Forbes-Watson, A. D. 1993. Checklist of birds of the Afrotropical and Malagasy regions. Tauraco Press, Li
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

Hydrobates monorhis Christidis and Boles (2008), Hydrobates monorhis monorhis Christidis and Boles (2008)

Distribution and population
Oceanodroma monorhis 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 (China), North Korea and South Korea, and records suggest that breeding possibly occurs 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).

Population justification
Brooke (2004) estimated the global population to number c.100,000 individuals, while Sato et al. (2010) estimate the world population at a minimum of 130,000 pairs; national population estimates include: c.100-10,000 breeding pairs and c.50-1,000 individuals on migration in China; c.100-100,000 breeding pairs and c.50-10,000 individuals on migration in Taiwan; c.100-100,000 breeding pairs and c.50-10,000 individuals on migration in Korea and c.100-100,000 breeding pairs and c.50-10,000 individuals on migration in Japan (Brazil 2009).

Trend justification
The population is expected to undergo a moderately rapid decline over the next three generations, owing primarily to the impact of introduced species.

This marine species can be found over pelagic and inshore waters. Its feeds mainly on the wing by dipping and does not patter. Breeding starts in April forming loose colonies on offshore islands in burrows (del Hoyo et al. 1992).

Sato et al. (2010) describe threats at breeding sites as including mining operations, introduced predators and tourism. On Koyashima, Fukuoka (Japan), the breeding colony was decimated by accidentally introduced brown rats Rattus norvegicus (Takeishi 1987 in Sato et al. 2010) and has not fully recovered despite predominantly successful eradication efforts (Sato et al. 2010, Takeishi per M. Sato in litt. 2011). The island of Okinoshima, only 1 km away, is inhabited by both black rats R. rattus and brown rats and is likely to be a source for the accidental introduction of rats to Koyashima in the future (M. Takeishi per M. Sato in litt. 2011). On Chilbaldo, South Korea, the species has been severely impacted by introduced plants, such as Mugwort Artemisia vulgaris and Achyranthes japonica, that, if tall and dense, prevent birds from entering their burrows (Lee 2010). In addition, Achyranthes japonica acts like a mass of hooks when the plants mature in September, and hundreds of O. monorhis perish when they fly into the plants and become trapped. Although work has been undertaken in the past to remove introduced plants from parts of the island, the problem posed by Achyranthes japonica now appears to be getting worse (Lee 2010). Invasive plants apparently affect all known breeding colonies in South Korea (Chang-Yong Choi in litt. 2012). Some colonies in Japan are threatened or potentially threatened by the activities of recreational visitors in warm seasons (Sato et al. 2010 and references therein). Disturbance from tourists visiting Gageo Island, South Korea, is increasingly likely to impact birds nesting on the nearby Gugeul Islets (Birds Korea 2010). Furthermore, Bentenjima Islet, Shiriyazaki (Japan), has been connected to the mainland to facilitate the mining of limestone, and breeding there is thought to have ceased (Sato et al. 2010). Intense fishing operations near the species’s breeding sites probably result in occasional landing by fishermen, increasing the risk of rats being introduced to other breeding colonies. In addition to anthropogenic threats, rocky islands with shallow soil that are inhabited by the species, such as the Kutsujima Islands, could suffer severe erosion during a typhoon or other heavy rainfall event, which would probably seriously affect colonies. Competition for nesting sites from species such as Streaked Shearwater Calonectris leucomelas, could negatively impact O. monorhis. Predation by gulls is another potential threat (Sato et al. 2010). Threats to the main breeding colony on Verkhovsky Island include predation by crows Corvidae and migrating owls Strigidae.

Conservation Actions Underway
The main colonies in South Korea are already dependent on active conservation measures, including the eradication of invasive alien species and prevention of disturbance (N. Moores in litt. 2011). The main breeding colony on Verkhovsky island has been protected since 1984 which has stopped disturbance of nests by tourists.

Conservation Actions Proposed
Carry out regular surveys to monitor population trends. Implement measures to control invasive species at as many affected colonies as possible. Mitigate the impact of tourism at relevant sites. Implement and enforce controls on landings by fishing boats.

Birds Korea. 2010. The Birds Korea blueprint 2010 for the conservation of the avian biodiversity of the South Korean part of the Yellow Sea. Birds Korea, Seoul.

Brazil, M. 2009. Birds of East Asia: eastern China, Taiwan, Korea, Japan, eastern Russia. Christopher Helm, London.

Brooke, M. De L. 2004. Albatrosses and petrels across the world. Oxford University Press, Oxford.

del Hoyo, J.; Elliot, A.; Sargatal, J. 1992. Handbook of the Birds of the World, vol. 1: Ostrich to Ducks. Lynx Edicions, Barcelona, Spain.

Lee K.-G. 2010. The status of seabirds on Sasu and Chilbal islands, and the management of invasive species. The Birds Korea Blueprint 2010 for the conservation of the avian biodiversity of the South Korean part of the Yellow Sea, Birds Korea, Busan.

Sato, F.; Karino, K.; Oshiro, A.; Sugawa, H.; Hirai, M. 2010. Breeding of Swinhoe’s Storm-petrel Oceanodroma monorhis in the Kutsujima Islands, Kyoto, Japan. Marine Ornithology 38: 133-136.

Text account compilers
Butchart, S., Calvert, R., Ekstrom, J., Fisher, S., Harding, M., Taylor, J.

Choi, C., Jayadevan, P., Moores, N., Sato, M., Takeishi, M.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Oceanodroma monorhis. Downloaded from on 16/04/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from on 16/04/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Key facts
Current IUCN Red List category Near Threatened
Family Hydrobatidae (Storm-petrels)
Species name author (Swinhoe, 1867)
Population size 260000 mature individuals
Population trend Stable
Distribution size (breeding/resident) 3,800 km2
Country endemic? No
Links to further information
- Additional Information on this species