DIET OF HERRING-GULLS LARUS-ARGENTATUS DURING CHICK REARING IN THE GULF OF FINLAND

We studied the diet of 40 focal pairs of Herring Gulls (Larus argentat us) in a colony off Hanko, western Gulf of Finland, during the 1993 br eeding season. During 161 feedings, fish was regurgitated in 70% of al l cases (mostly Clupea harengus or C. sprattus, when the fish could be identified). Fish was brought to all territories at least once (mean number of feeding observations per pair was 4.3), and only 9 pairs fed Eider (Somateria mollissima) chicks to their offspring, together 11% of all feedings observed. Garbage and offal occurred in 10% of the fee dings. Most pairs thus used fish. Fish is the best available food for chicks, since it has a high nutritive value and is easy to handle.