Abstract
Chick growth and parental feeding behavior of the Spectaled Guillemot (Cepphus carbo) were studied on Teuri Island, Hokkaido in 1989. Increase in chick body weight was closely fitted to the von Bertalanffy equation. Chick growth rate peaked at a maximum of 22.1g/day at 15.3 days after hatching; being highest among the Alcidae. Its weight was 620g at fledging, 91.2% of the average adult weight. Lengths of wing, culmen and tail for two chicks grew to 60-79% of adult lengths at fledging, with only the tarsus attaining the full length. Chick diets in the nestling period consisted of three species of benthic fishes, Sebastes minor, Ammodytes personatus, and Blennioidei sp. Feeding frequency was 9.8 times/day for one chick brood, and 9.3 times/day for two chick broods. These figures are remarkably high compared to other Alcidae. High feeding ability of the parents may account for high growth rates and large body sizes at fledging for the chicks.
