The Flannan Isles are a group of six rocky islands, with outlying skerries, which lie about 30 km west of Lewis in the Outer Hebrides off the north-west coast of Scotland. They provide a strategically placed nesting locality for seabirds, which feed in the rich waters off the Western Isles. The vegetation of the islands is predominantly maritime grassland. The islands are an important nesting area for a variety of seabird species, especially auks, but including Leach's Petrel Oceanodroma leucorhoa, for which they are one of only seven known nesting localities in the EU. The seabirds feed outside the SPA in nearby waters, as well as more distantly in the North Atlantic.