The mudflats are an important habitat for many bird species, and over 100 species have been recorded at the reserve, with the highest numbers seen during the spring and autumn migrations. Species that spend the winter at the loch include bar-tailed godwit, greylag goose, wigeon, curlew, dunlin, and teal. Approximately 2 % of the entire UK population of greylag geese use the wider Dornoch Firth and Loch Fleet SPA, with Loch Fleet being particularly important during the autumn: as winter progresses many of the geese move on to the Dornoch Firth. The geese spend summers further north, with some heading for Iceland and some remaining within Scotland at sites in Caithness and Sutherland.