Synthliboramphus wumizusume 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Charadriiformes Alcidae

Scientific Name: Synthliboramphus wumizusume
Species Authority: (Temminck, 1835)
Common Name(s):
English Japanese Murrelet, Crested Murrelet
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International.
Identification information: 26 cm. Small alcid. Short, thick, pale bluish-grey bill. Black head with black crest (summer only) and white stripes on sides of head from top of eyes, meeting on nape. Blackish and bluish-grey upperparts. White throat and underparts. Greyish-black flanks. Yellowish-grey legs and feet. Juvenile has browner upperparts. Similar spp. Ancient Murrelet S. antiquus lacks crest and has black on throat.

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2cde+3cde+4cde;C2a(ii) ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Ono, K.
Facilitator/Compiler(s): Anderson, O., Benstead, P., Calvert, R., Gilroy, J., Khwaja, N., Taylor, J.
This species has a small population which is thought to be declining rapidly as a result of disturbance at breeding sites, predation and mortality from drift-net fisheries. It is therefore listed as Vulnerable.

Previously published Red List assessments:
2010 Vulnerable (VU)
2008 Vulnerable (VU)
2007 Vulnerable (VU)
2005 Vulnerable (VU)
2004 Vulnerable (VU)
2000 Vulnerable (VU)
1996 Vulnerable (VU)
1994 Vulnerable (VU)
1988 Threatened (T)

Geographic Range [top]

Range Description: Synthliboramphus wumizusume is endemic to the warm current regions near central and southern Japan, where it breeds on uninhabited islands (BirdLife International 2001). The most important breeding sites are in Kyushu, notably the islands of Biro-jima, Koya-jima and Eboshi-jima, and the Izu Islands, notably Onbase-jima and Onohara-jima. Breeding has also been recorded on Gugul Island off the southern coast of South Korea, and it may also breed in Peter the Great Bay, Primorye, Russia. After breeding, birds move northwards to an area south-east of Hokkaido. They also winter along the coasts of Honshu and Kyushu, some birds apparently moving south to the Nansei Shoto Islands. The population is unlikely to exceed 10,000 mature individuals. It is still declining in many localities, particularly the Izu Islands (Carter et al. 2002).

Countries occurrence:
Japan; Korea, Republic of; Russian Federation
Taiwan, Province of China
Estimated area of occupancy (AOO) - km2: 110
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 110
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Number of Locations: 11-100
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The global population is roughly estimated to be in the band c.2,500-9,999 mature individuals (Ono 1996 and BirdLife International 2001), equating to 3,750-14,999 individuals, rounded here to 3,500-15,000 individuals. National population sizes have been estimated at < c.100 breeding pairs and c.50-1,000 individuals on migration in Korea and c.100-10,000 breeding pairs and c.50-1,000 wintering individuals in Japan (Brazil 2009).

Trend Justification:  Populations are thought to be declining rapidly through the combined impact of predation by introduced rats, disturbance of breeding sites and adult mortality in fishing nets.

Current Population Trend: Decreasing
Additional data:
Number of mature individuals: 2500-9999 Continuing decline of mature individuals: Yes
Extreme fluctuations: No Population severely fragmented: No
No. of subpopulations: 1 Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: Yes
No. of individuals in largest subpopulation: 100

Habitat and Ecology [top]

Habitat and Ecology: It frequents rocky islets and headlands during the breeding season (between mid-February and early May), nesting in single pairs, small groups and sometimes in large colonies. In the non-breeding season it occurs offshore, occasionally entering bays. Juveniles have recently been sighted outside the breeding season in the Seto Inland Sea, an area previously thought unsuitable for Japanese Murrelet, at least 150 km from the nearest known breeding site (Iida 2008). This was confirmed by the sighting of several family parties around the south-west of Yashima Island in the western Seto Inland Sea (Iida 2010). Two adult and two chicks with down, seen close to the coast of Tateyama City at the south end of Boso peninsula, point to other unknown breeding locations, as these sightings were 70 km from the nearest known breeding islands (Fujita 2008). 

Systems: Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 12.1
Movement patterns: Not a Migrant
Congregatory: Congregatory (and dispersive)

Threats [top]

Major Threat(s): Sport fishing on isolated offshore reefs and islets is a major threat as it causes direct disturbance and habitat degradation. Fish, discarded by anglers, attract crows and gulls which then predate eggs and chicks. Indeed, predation by crows is the main threat on Biro-jima and Onohara-jima. Brown rat Rattus norvegicus has been introduced to some nesting colonies and has almost extirpated the population on Koya-jima, after rats had been successfully eradicted in 1987/1988 until 2006 when they were reintroduced, and then possibly eradicated for a second time. Landings by fishermen pose a continuing threat of rat reintroduction (M. Sato in litt. undated). Annual mortality of adults in drift-nets has been estimated at 1-10% of the total breeding population, but these figures may be underestimates. There is some evidence that fish stocks have declined around the Izu Islands because of changes in water temperature. Oil spills are a potential threat.

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
CMS Appendix I. It is legally protected in Japan. In addition to the several breeding colonies already protected as national wildlife protection areas, including Nanatsu-jima, Kiinagashima, Okino-jima and Danjo-gunto, in November 2010 Biro-jima, Tadanae Island, Ohnohara-jima and Kanmuri-jima also received this designation (K. Ono in litt. 2012). Gugul Islet (South Korea) has been designated as a Natural Monument. In Japan, educational materials have been produced to inform fishers about the species and the importance of the largest known breeding colony on Biro-jima Island.

Conservation Actions Proposed
Conduct coordinated surveys of breeding sites to determine current population size and trends. Establish new protected areas at important colonies that are not officially protected. Restrict human access to islands with breeding colonies. Control predators at breeding colonies. Research and design methods to reduce the bycatch of seabirds by fisheries.

Citation: BirdLife International. 2012. Synthliboramphus wumizusume. The IUCN Red List of Threatened Species 2012: e.T22694899A38901747. . Downloaded on 25 May 2016.
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