ABSTRACT Diverse factors may limit nest-site selection; however, nest predation has long been considered a main factor driving nest-site selection in birds. Marsh-nesting birds face a particularly important trade-off between habitat features that impede their vision of the approach of potential predators and nest concealment from predators. Here, we analyse how different ecological variables influence nest-site selection in the habitat-specialist Wren-like Rushbird (Phleocryptes melanops) breeding in three different wetlands of the Pampas region of Argentina over 3 years. Rushbirds selected nest sites with higher heights and denser vegetation, compared to random sites. Nest height was positively associated with vegetation height and lower visibility from the point of view of aerial predators, and the nest entrance was oriented towards the region with greatest visibility of the nest from the point of view of Rushbirds. Rushbirds seem to flexibly adjust their nest location in response to high predation risk, building their nests under structures built by other birds when breeding colonies of herons and gulls (potential nest predators) are present. Initial nest-site selection is performed by males, which then attempt to attract females to a rudimentary nest. Females sometimes reject such sites and the male then selects a new nesting location. Our study highlights the potential for flexible sex differences in nest-site selection.

中文翻译：

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与湿地专家鹪鹩类 Rushbird (Phleocryptes melanops) 的巢址选择相关的多种因素

摘要 多种因素可能会限制巢址的选择；然而，长期以来，巢穴捕食一直被认为是推动鸟类选择巢穴的主要因素。在沼泽筑巢的鸟类面临着栖息地特征之间的一个特别重要的权衡，这些特征阻碍了它们对潜在捕食者的接近的视野和对捕食者的巢穴隐藏。在这里，我们分析了不同的生态变量如何影响栖息地专家 Wren-like Rushbird (Phleocryptes melanops) 在 3 年内在阿根廷潘帕斯地区的三个不同湿地繁殖的巢址选择。与随机地点相比，Rushbirds 选择的筑巢地点具有更高的高度和更密集的植被。从空中捕食者的角度来看，巢穴高度与植被高度和较低的能见度呈正相关，从 Rushbirds 的角度来看，巢穴入口朝向巢穴可见度最大的区域。Rushbirds 似乎会灵活地调整它们的巢穴位置以应对高捕食风险，当苍鹭和海鸥（潜在的巢穴捕食者）繁殖群出现时，它们会在其他鸟类建造的结构下筑巢。最初的巢址选择是由雄性进行的，然后试图将雌性吸引到一个基本的巢穴中。雌性有时会拒绝这样的地点，然后雄性会选择一个新的筑巢地点。我们的研究强调了在巢址选择中灵活的性别差异的潜力。当苍鹭和海鸥（潜在的巢内掠食者）繁殖群出现时，在其他鸟类建造的结构下筑巢。最初的巢址选择是由雄性进行的，然后试图将雌性吸引到一个基本的巢穴中。雌性有时会拒绝这些地点，然后雄性会选择一个新的筑巢地点。我们的研究强调了在巢址选择中灵活的性别差异的潜力。当苍鹭和海鸥（潜在的巢穴掠食者）繁殖群出现时，在其他鸟类建造的结构下筑巢。最初的巢址选择是由雄性进行的，然后试图将雌性吸引到一个基本的巢穴中。雌性有时会拒绝这样的地点，然后雄性会选择一个新的筑巢地点。我们的研究强调了在巢址选择中灵活的性别差异的潜力。