Treshnish Isles

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
European Storm-petrel Hydrobates pelagicus LC breeding 1996 5,050 breeding pairs A4ii, B1ii, B2, C2, C6
European Shag Gulosus aristotelis LC breeding 1999 601 breeding pairs B3
Great Black-backed Gull Larus marinus LC breeding 1999 342 breeding pairs B3
A4iii Species group - seabirds n/a breeding 1996-2000 16,580 breeding pairs A4iii, C4

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 very unfavourable medium
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
Human intrusions and disturbance recreational activities 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
Branta leucopsis Barnacle Goose 565 20 individuals 4 very unfavourable
Gulosus aristotelis European Shag 105 601 breeding pairs 100 favourable
Larus marinus Great Black-backed Gull 265 342 breeding pairs 100 favourable
Species group - seabirds A4iii 16913 16580 breeding pairs 99 favourable

Conservation actions taken at site (response)
Conservation Designation Management Planning Conservation Action Result
Whole area of site (>90%) covered by appropriate conservation designation A management plan exists but it is out of date or not comprehensive Substantive conservation measures are being implemented but these are not comprehensive and are limited by resources and capacity medium
For more information about IBA monitoring please click here

IBA Protection

Protection status:

Protected Area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)
Treshnish Isles Site of Special Scientific Interest (UK) 242 protected area overlaps with site 208
Treshnish Isles Special Protection Area (Birds Directive) 242 protected area overlaps with site 239
Treshnish Isles Site of Community Importance (Habitats Directive) 1,963 protected area overlaps with site 195
Treshnish Isles Marine Protected Area (OSPAR) 0 protected area overlaps with site 0
Loch na Keal, Isle of Mull National Scenic Area 44,250 protected area contains site 0
Inner Hebrides and the Minches Site of Community Importance (Habitats Directive) 1,380,199 protected area overlaps with site 0


IUCN Habitat Habitat detail Extent (% of site)
Shrubland Heathland -
Grassland -
Coastline Sea cliffs and rocky shores, Scree and boulders -
For further information about the habitat classification please click here.

Land use

Land-use Extent (% of site)
not utilised -
For further information about the land use classification please click here.

Recommended citation
BirdLife International (2020) Important Bird Areas factsheet: Treshnish Isles. Downloaded from on 28/09/2020.