Data Zone
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 IBA criteria.
Populations meeting IBA criteria ('key 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 |
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 status | |||
|---|---|---|---|
| Year of assessment | State | Pressure | Response |
| 2015 | favourable | high | medium |
| Whole site assessed? | State assessed by | Accuracy of information | |
| yes | habitat | - | |
| State (condition of the key species' habitats) | |||
|---|---|---|---|
| Habitat | Quantity (% remaining) | Quality (% carrying capacity) | Result |
| Forest | good (>90%) | good (>90%) | favourable |
| Pressure (threats to the key species and/or their habitats) | ||||
|---|---|---|---|---|
| Threat | Timing | Scope | Severity | Result |
| Invasive and other problematic species and genes | likely in long term (beyond 4 years) | whole population/area (>90%) | moderate deterioration (10–30% in 3 generations) | high |
| Response (conservation actions taken for the key species and/or their habitats) | |||
|---|---|---|---|
| Designation | Planning | Action | Result |
| Whole area of site (>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 |
| 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 |
| Habitat | % of IBA | Habitat detail |
|---|---|---|
| Forest | - | |
| Marine Coastal/Supratidal | - |
Recommended citation
BirdLife International (2025) Important Bird Area factsheet: Okinoshima and Koyajima islets (Japan). Downloaded from
https://datazone.birdlife.org/site/factsheet/okinoshima-and-koyajima-islets-iba-japan on 22/01/2025.