THE HABITAT ASSOCIATIONS OF DUNLIN (CALIDRIS-ALPINA) IN THE FLOW COUNTRY OF NORTHERN SCOTLAND AND AN IMPROVED MODEL FOR PREDICTING HABITAT QUALITY

1. A previous study in the Flow Country of northern Scotland has shown that variation in the abundance of dunlin (Calidris alpina schinzii B rehm) can be predicted from the near-infrared reflectance of moorland derived from satellite imagery. Low reflectance corresponds to high de nsities of dunlin and vice versa. 2. Here we report further evidence f or this relationship. 3. Dunlin are closely associated with wet areas of moorland containing pool-systems and water strongly absorbs near-in frared radiation. Consequently, it was hypothesized that moorland with many pool-systems would tend to have low near-infrared reflectance an d large numbers of dunlin. 4. Results presented here suggest that this hypothesis is incorrect. Variations in pool-system area do not greatl y influence near-infrared reflectance. Dunlin abundance is a function of both pool-system area and the characteristics of the matrix between water bodies. 5. Although matrix variation is important in determinin g dunlin density, dunlin nevertheless show strong avoidance of the mat rix at fine spatial scales by clustering in and around pool-systems. T his avoidance is similar in strength regardless of matrix type. Pool-s ystems are occupied preferentially wherever they are present, but the density of birds on pool-systems varies depending on the nature of the surrounding matrix.