Canna and Sanday are two adjacent basaltic islands in the Small Isles, north-west of Rum in the Lochaber district of the Scottish Highlands. Canna is ringed with steep cliffs and is capped by a ridge of wet heath and maritime blanket bog. Sanday and low-lying parts of Canna support coastal grassland and maritime heath. The islands are particularly important for their breeding seabird colonies (including gulls, auks and Shag Phalacrocorax a. aristotelis). The seabirds feed outside the SPA in the nearby waters, as well as more distantly.