Pulido F J, Díaz M
Departamento de Biología Animal I (Vertebrados), Facultad de Biología, Universidad Complutense, E-28040 Madrid, Spain, , , , , , ES.
Oecologia. 1997 Jul;111(3):434-442. doi: 10.1007/s004420050256.
In spite of recent theoretical interest, few field studies have addressed the links between individual behavioral decisions and population distribution. This work analyzes the foraging behavior of individuals and the spatial distribution of a population of blue tits (Parus caeruleus) just before the main breeding season, when blue tit foraging was not affected by central-place or flocking behaviors. The study was carried out in open holm oak Quercus ilex woodlands (dehesas) that are patchy for canopy-foraging birds because of the scattered arrangement of trees. Residence time on each tree was not correlated either with previous flight time or with prey abundance in trees. Flight distances between trees were larger than average distances estimated in random samples of holm oaks taken close to foraging birds. Trees were not selected by birds on the basis of their expected energy costs and rewards. Bird abundance was not related to food availability in trees or to tree size across dehesas. However, bird abundance was strongly correlated with tree density and with the availability of tree holes for nesting, to the extent that the proportion of tits matched the proportions of both tree abundance and hole abundance across study plots. Overall, neither the behavior of individuals nor the distribution of the population of blue tits corresponded with food resources, which appeared superabundant; instead, tits appeared to behave and be distributed according to the distribution of structural resources such as trees and tree holes for nesting.
尽管近期有理论兴趣，但很少有实地研究探讨个体行为决策与种群分布之间的联系。这项工作分析了蓝山雀（Parus caeruleus）种群在主要繁殖季节前个体的觅食行为和空间分布，此时蓝山雀的觅食不受中心地或集群行为的影响。该研究在开阔的圣栎（Quercus ilex）林地（德埃萨）中进行，对于树冠觅食鸟类来说，由于树木的分散排列，这些林地是零散分布的。在每棵树上的停留时间与之前的飞行时间或树上的猎物丰度均无关联。树木之间的飞行距离大于在靠近觅食鸟类处随机抽取的圣栎样本中估计的平均距离。鸟类并非根据预期的能量成本和回报来选择树木。在整个德埃萨地区，鸟类丰度与树上的食物可利用性或树木大小均无关联。然而，鸟类丰度与树木密度以及可供筑巢的树洞可利用性密切相关，以至于在各个研究地块中，山雀的比例与树木丰度和树洞丰度的比例相匹配。总体而言，蓝山雀个体的行为和种群分布均与看似极为丰富的食物资源不相符；相反，山雀的行为和分布似乎是根据诸如树木和可供筑巢的树洞等结构资源的分布来进行的。
