Inter-colony variation in foraging flight characteristics of black-headed gulls Chroicocephalus ridibundus during the incubating period

Using GPS-loggers, we examined the influence of colony, sex, and bird identity on foraging flight characteristics of black-headed gulls Chroicocephalus ridibundus during the incubation period. We studied tracks of 36 individuals breeding in one urban and two rural colonies in Poland. Birds from both rural colonies performed the furthest flights (mean 8-12 km, up to 27 km) foraging mainly in agricultural areas. Gulls from the urban colony performed shorter flights (median 5 km, up to 17 km) visiting mainly urbanized areas and water bodies. We found that females performed longer flights and their flights parameters were less repeatable compared to males. Males from both rural colonies visited water bodies more frequently than females. In all colonies males (but not females) used habitats unproportionally to their availability in the vicinity. Relatively low inter-individual and relatively high intra-individual overlap in home ranges indicated considerable foraging site fidelity. Individua...