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Location Japan, Tokyo
Central coordinates 139o 36.00' East  33o 52.00' North
IBA criteria A1, A2, A4ii
Area 2,058 ha
Altitude 0 - 850m
Year of IBA assessment 2004

Wild Bird Society of Japan

Site description Mikurajima, which is located about 200 km south-southeast of Tokyo metropolitan area, is a volcanic island with the circumference of 16 km. There are abrasion cliffs along the coastline with no beach. About a half of the island is dominated by primary forests of Castanopsis cuspdata trees. The forests have unique vegetation which includes both northern plants and the southern ones. Alpine plants are found from the area around 450 m above the sea level to the mountaintop, while subtropical plants are luxuriant below the 350 m level. This island has one of the largest breeding sites of Streaked Shearwater in the world, where about two million birds breed.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Streaked Shearwater Calonectris leucomelas breeding  2004  present  A4ii  Near Threatened 
Japanese Murrelet Synthliboramphus wumizusume breeding  2004  present  A1, A4ii  Vulnerable 
Japanese Woodpigeon Columba janthina resident  2004  present  A2  Near Threatened 
Pleske's Grasshopper-warbler Locustella pleskei breeding  2004  present  A1  Vulnerable 
Izu Leaf-warbler Phylloscopus ijimae breeding  2004  present  A1, A2  Vulnerable 
Izu Thrush Turdus celaenops resident  2004  present  A1, A2  Vulnerable 

IBA Monitoring

2010 low not assessed low

Biological resource use hunting & collecting terrestrial animals - persecution/control likely in long term (beyond 4 years) some of area/population (10-49%) no or imperceptible deterioration low

Whole area of site (>90%) covered by appropriate conservation designation  A management plan exists but it is out of date or not comprehensive  Unknown  low 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Fuji-Hakone-Izu National Park 122,690 protected area contains site 2,058  


IUCN habitat Habitat detail Extent (% of site)
Forest   -
Coastline Rock stacks and islands  -

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Mikurajima island. Downloaded from on 24/10/2016

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