JP136
Okinoshima and Koyajima islets


IBA Justification

The site was identified as internationally important for bird conservation in 2004 because it was regularly supporting significant populations of the species listed below, meeting ('triggering') IBA criteria.

Populations meeting IBA criteria ('trigger species') at the site:
Species Red List Season (year/s of estimate) Size IBA criteria
Japanese Woodpigeon Columba janthina LC resident (2003) present A2
Streaked Shearwater Calonectris leucomelas NT breeding (2003) present A4ii
Japanese Murrelet Synthliboramphus wumizusume VU breeding (2003) present A1, A4ii
Pleske's Grasshopper-warbler Helopsaltes pleskei VU breeding (2003) present A1

IBA Conservation

Ideally the conservation status of the IBA will have been checked regularly since the site was first identified in 2004. The most recent assessment (2015) is shown below.

IBA conservation assessment
Year of assessment State Pressure Response
2015 good high medium
Whole site assessed? State assessed by Accuracy of information
yes habitat -

State (condition of the trigger species' habitats)
Habitat Quantity (% remaining) Quality (% carrying capacity) Result
Forest good (>90%) good (>90%) good

Pressure (threats to the trigger species and/or their habitats)
Threat Timing Scope Severity Result
Invasive and other problematic species and genes likely in long term (>4 years) whole of popul­ation/area (>90%) moderate decline (10–30% over 3 gener­ations) high

Response (conservation actions taken for the trigger species and/or their habitats)
Designation Planning Action Result
Whole area (>90%) covered by appropriate conservation designation A compre­hensive and appropriate management plan exists that aims to maintain or improve the populations of qualifying bird species Very little or no conservation action taking place medium

IBA Protection

Year Protected Area Designation (management category) % coverage of IBA
1983 Okinoshima 都道府県自然環境保全地域 (V) 95
1984 Okinoshima 国指定鳥獣保護区 (IV) 100
2003 Common fishery right area(Fukuoka) 共同漁業権区域 (VI) 3

Habitats

Habitat % of IBA Habitat detail
Forest -
Marine Coastal/Supratidal -


Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Okinoshima and Koyajima islets (Japan). Downloaded from https://datazone.birdlife.org/site/factsheet/okinoshima-and-koyajima-islets-iba-japan on 23/12/2024.