The diet of breeding dippers Cinclus cinclus cinclus and their nestlings in southwestern Norway

The diet of dippers in south west Norway was investigated by faecal analysis during the 1985 breeding season. Overall, the diets of adults and nestlings were similar and consisted mostly of nymphs and larvae of Baetidae (mayflies). Leuctridae/Nemouridae (stoneflies). Hydropsychidae, Limnephilidae and Rhyaeophilidae (caddisflies). However, strong trends were apparent with nestling age: large items such as caddisflies declined in adult diet but increased in nestling diet as the chicks grew. The pattern probably reflected the growing energy demands of the brood in a central-place. Because some of the items of dietary importance are scarce in acidic streams, we stress the need for research on the influences of acidification on the ecology of Scandinavian dippers.