Atlantic Puffin (Fratercula arctica) chick growth, diet, feeding rate and early survival and adult body condition were quantified on Hornøya, North Norway in 2002 and 2003 after a long-term change in diet from large Capelin (Mallotus villosus) and Sand Lance (Ammodytes spp.) in the early 1980s to smaller, poorer quality gadids, Sand Lance and Herring (Clupea harengus). The results were compared with data collected in 1980-1982, when feeding conditions were considered very favourable. Chick growth was similar in both periods. The breeding adults compensated for reduced food quality by increasing the feeding frequency, such that the chicks received the same amount of fish (g d^-1 and kJ d^-1) or even more in 2002-2003. This increase in activity did not, however, result in a decline in adult body mass, suggesting that prey were abundant close to the colony and that the parents did not suffer from the apparent increased feeding effort.