Distribution of Puffins Fratercula arctica feeding off Røst, northern Norway, during the breeding season, in relation to chick growth, prey and oceanographical parameters

In 1988, first-year Herring Clupea harengus were the dominant prey fed to Puffin chicks on Hernyken, Røst. Puffins carrying food loads were observed at least 137 km from the colonies in July. In early August, two major feeding areas were located about 20 and 85-105 km off Røst. These long foraging ranges and an insufficient availability of food are thought to be the main reasons for the poor chick growth this year. No relationships were found between the distribution of Puffins observed at sea and survey station data on prey distribution, sea temperature or salinity, but this may have been due to inadequate sampling of these parameters. A recorded seasonal change in flight direction of adults returning to colony is discussed in relation to food quality and chick growth.