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...本研究借助GPS记录器（GPS-loggers），针对孵化期红嘴鸥（Chroicocephalus ridibundus）的觅食飞行特征，探究了繁殖群属性、性别以及个体身份对其产生的影响。我们对波兰1座城市繁殖群与2座乡村繁殖群中的36只繁殖个体的飞行轨迹展开了分析。来自两处乡村繁殖群的红嘴鸥飞行距离最远（平均8~12千米，最远可达27千米），主要于农业区域觅食；而城市繁殖群的红嘴鸥飞行距离较短（中位数为5千米，最远可达17千米），其觅食活动多集中在城市化区域与水体周边。研究结果显示，雌性红嘴鸥的飞行距离更长，且飞行参数的重复性较雄性更低。两处乡村繁殖群中的雄性红嘴鸥造访水体的频率均高于雌性个体。在所有繁殖群中，雄性（而非雌性）对栖息地的利用比例与其周边栖息地的可获得性不成正比。家域范围的个体间重叠度相对较低、个体内重叠度相对较高，这表明红嘴鸥具备显著的觅食位点忠实性。