DO WHITE PELICANS PELECANUS-ONOCROTALUS BENEFIT FROM FORAGING IN FLOCKS USING SYNCHRONOUS FEEDING

White Pelicans Pelecanus onocrotalus foraging at Lake Nakuru, Kenya, s pent most of their time in flocks of two to several tens of individual s, and most flocks adopted a synchronized fishing behaviour. However, the maximum capture rate when feeding was attained by solitary individ uals, and it decreased non-linearly as flock size increased. Individua ls in non-synchronized flocks had a higher capture rate than those in synchronized flocks of the same size. The total number of bill probes decreased with the size of synchronized flocks, but this reduction in foraging costs did not compensate for the decrease in capture rate, si nce the ratio of successful probes to total probes did not increase wi th flock size. We discuss some hypotheses that might explain the parad oxical result that most White Pelicans aggregate into flocks and synch ronize their behaviour and yet they attain a lower capture rate than t hose foraging alone.