Inner Hebridean island group with high craggy cliffs, machair, sand-dunes, heathland and farmed areas. A herb-rich sward occurs under the influence of sea spray, while the mainly acidic underlying rock supports wet, dry and maritime heaths.
First identified in 1989; extended and renamed from North Colonsay and Western Cliffs in 1992. Descriptive text and bird data refer to the 2000 Inventory.
The IBA also holds 11,000 pairs of breeding seabirds on a regular basis, and is also nationally important for breeding Crex crex (globally threatened: 8 calling males, 1996, 2%), Rissa tridactyla (5,650 pairs, 1986, 1%) and Uria aalge (9,050 pairs, 1986, 1%), and for wintering Anser albifrons flavirostris (200 birds, 1%). Branta leucopsis are from the Greenland breeding population.
Pressure/threats to key biodiversity
Tern colonies are under increasing pressure from disturbance by tourists. The RSPB lease and manage Oronsay.