Fish orientation in the bill of Black GuillemotsCepphus grylle

Abstract

The orientation of fish in the bill of Black Guillemots feeding young was studied in 1983–84 at a Shetland colony. Observations of marked birds revealed that only 20% of individuals exhibited a significant orientation preference, and that few showed strong preferences. Only one bird showed a consistent significant preference in both years. It is suggested that regular use of specific foraging sites may be an important factor in explaining apparent handedness, since adults might try to minimize the drag caused by long, flapping fish by holding the head pointing into wind.