Eating locally: Australasian gannets increase their foraging effort in a restricted range.
Eating locally: Australasian gannets increase their foraging effort in a restricted range.
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DOI：
10.1242/bio.013250
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发表时间：
2015-09-14
期刊：
影响因子：
2.4
通讯作者：
Arnould JP
中科院分区：
文献类型：
--
作者：
Angel LP;Barker S;Berlincourt M;Tew E;Warwick-Evans V;Arnould JP
在繁殖季节，海鸟采用中心位置觅食策略，其觅食范围受到配偶/雏鸟的禁食能力以及在猎物资源和巢之间来回奔波的成本的限制。由于海洋生态系统的时空变异性，个体必须调整自己的行为，以在这些限制范围内增加觅食成功。在三个猎物丰度明显不同的连续繁殖季节中，研究了澳大拉西亚麻雀(Morus Serrator)的海上活动、觅食行为和努力程度，以调查该物种如何适应食物供应的年际波动。利用GPS和三轴加速度计数据记录器比较了位于两个较大的邻近群体之间的一个小鹅群在两个繁殖阶段(孵化和养鸡)内的年变化程度。有趣的是，雄性和雌性都没有增加在任何繁殖阶段的总旅行距离或觅食旅行的持续时间(在所有情况下P>；0.05)，尽管猎物可获得性明显较低。然而，在每个繁殖阶段，平均向量动态身体加速度(一个能量消耗指数)在繁殖成功较差的年份(增加了三到八倍)更大，这表明鸟类在它们的范围内工作得更努力。此外，在两个繁殖阶段中，雄性和雌性都增加了在较贫穷的年份进行觅食旅行的比例。在猎物可获得性低的年份，这个群体的个体可能会受到限制，因为来自附近群体的同种物种的竞争，可能会限制他们扩大范围的能力，从而增加在这个受限的觅食区域内的觅食努力。
During the breeding season, seabirds adopt a central place foraging strategy and are restricted in their foraging range by the fasting ability of their partner/chick and the cost of commuting between the prey resources and the nest. Because of the spatial and temporal variability of marine ecosystems, individuals must adapt their behaviour to increase foraging success within these constraints. The at-sea movements, foraging behaviour and effort of the Australasian gannet (Morus serrator) was determined over three sequential breeding seasons of apparent differing prey abundance to investigate how the species adapts to inter-annual fluctuations in food availability. GPS and tri-axial accelerometer data loggers were used to compare the degree of annual variation within two stages of breeding (incubation and chick rearing) at a small gannet colony situated between two larger, nearby colonies. Interestingly, neither males nor females increased the total distance travelled or duration of foraging trip in any breeding stage (P>0.05 in all cases) despite apparent low prey availability. However, consistently within each breeding stage, mean vectorial dynamic body acceleration (an index of energy expenditure) was greater in years of poorer breeding success (increased by a factor of three to eight), suggesting birds were working harder within their range. Additionally, both males and females increased the proportion of a foraging trip spent foraging in a poorer year across both breeding stages. Individuals from this colony may be limited in their ability to extend their range in years of low prey availability due to competition from conspecifics in nearby colonies and, consequently, increase foraging effort within this restricted foraging area.