DAY AND NIGHT FEEDING IN DUNLINS CALIDRIS-ALPINA - CHOICE OF HABITAT, FORAGING TECHNIQUE AND PREY

The diurnal and nocturnal foraging behaviour of Dunlins Calidris alpina was investigated during their autumn migration in the Danish Wadden Sea. Dunlins fed regularly by both day and night. However, they tended to utilize different habitats during daytime and night-time, with relatively more birds aggregating on soft sediment containing high densities of Corophium volutator at night. Pecking was the dominant foraging technique during the daytime, whereas probing was the preferred technique at night. Dropping analysis revealed quantitative differences between the birds' diurnal and nocturnal diets. It is proposed that nocturnal foraging may be important for restoring fat deposits in migrating birds.