The Oa

IBA Criteria

Year of most recent IBA criteria assessment: 2007

Populations of IBA trigger species
Species Current IUCN Red List Category Season Year(s) of estimate Population estimate IBA Criteria Triggered
Greater White-fronted Goose Anser albifrons LC winter 1988-1989 1,490 individuals B1i, C2, C3, C6
Red-billed Chough Pyrrhocorax pyrrhocorax LC resident 2006 7 breeding pairs C6

Note: This table presents the IBA criteria triggered and the species that triggered then at the time of assessment, the current IUCN Red List category may vary from that which was in place at that time.

For more information about the IBA assessment process and criteria please click here

IBA Monitoring

Most recent IBA monitoring assessment
Year of assessment Threat score (pressure) Condition score (state) Action score (response)
2007 medium favourable low
Was the whole site covered? Yes State assessed by Population
Accuracy of information good

Threats to the site (pressure)
Threat Level 1 Threat Level 2 Timing Scope Severity Result
Agricultural expansion and intensification livestock farming and ranching (includes forest grazing) - small-holder grazing, ranching or farming happening now some of area/population (10-49%) slow but significant deterioration medium

Condition of key/trigger populations (state)
Scientific Common TargetPop ActualPop Units Remaining Result
Pyrrhocorax pyrrhocorax Red-billed Chough 7 7 breeding pairs 100 favourable

Conservation actions taken at site (response)
Conservation Designation Management Planning Conservation Action Result
Some of site covered (10-49%) A management plan exists but it is out of date or not comprehensive Substantive conservation measures are being implemented but these are not comprehensive and are limited by resources and capacity low
For more information about IBA monitoring please click here

IBA Protection

Protected Area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)
The Oa Nature Reserve 2,154 protected area contained by site 0
The Oa Site of Special Scientific Interest (UK) 1,931 protected area overlaps with site 0
The Oa RSPB Reserve 2,154 protected area contained by site 2,154
The Oa Special Protection Area (Birds Directive) 1,931 protected area overlaps with site 0
Laggan; Islay Special Protection Area (Birds Directive) 1,226 protected area is adjacent to site 0
Laggan Peninsula and Bay Site of Special Scientific Interest (UK) 1,230 protected area is adjacent to site 0


IUCN Habitat Habitat detail Extent (% of site)
Shrubland Heathland -
Wetlands (inland) Blanket bogs -
Coastline Sea cliffs and rocky shores -
Artificial/Terrestrial Arable land -
Marine Coastal/Supratidal -
For further information about the habitat classification please click here.

Land use

Land-use Extent (% of site)
agriculture -
forestry -
For further information about the land use classification please click here.

Recommended citation
BirdLife International (2023) Important Bird Areas factsheet: The Oa. Downloaded from on 25/03/2023.