For secondary cavity-nesting bird species that do not add lining materials to nests, the presence of old nest material or organic remains that have accumulated within nest cavities from previous breeding events may be a cue of nest-site quality. These materials potentially contain information about past breeding success in con- and heterospecifics and may improve the thermal insulation of eggs during incubation. However, few studies have addressed whether the presence of old nest materials serves as a cue for cavity-nesting raptors when choosing specific nest sites. We conducted a 9-year nest box experiment to test whether old nest materials from con- and heterospecifics serve as informative cues to the European Kestrel (Falco tinnunculus) when making nest selection decisions, as this species uses nest boxes without adding nesting material. The presence of old nest materials and entrance size best discriminated nest boxes occupied by European Kestrels from unoccupied boxes. Nest boxes containing conspecific organic remains, artificial dry leaf and branch material, and material left behind by Great Tits (Parus major) were reused at higher rates, especially those containing conspecific nest material, than nest boxes containing true or simulated nest materials from predators. In 2010, no single nest box was occupied by the same banded individual that occupied the box in the previous year (10 females and 2 males were banded in 2009). European Kestrels preferred nest boxes containing old nest material over empty boxes, which is consistent with previous findings that they exploit con- and heterospecific cues when deciding where to settle and breed, as old nest or organic material provides substrate for incubating females. Kestrels may be able to assess the predation risks associated with a specific nest site based on experience or the presence of prey remains. The repeated use of nest boxes across breeding seasons by kestrels cannot be entirely ascribed to philopatry. This study provides evidence that old nest materials are potentially used as informative cues when making nest-site selection decisions in European Kestrels.

中文翻译：

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在欧洲红est（Falco tinnunculus）中，使用旧巢材料可作为做出巢位选择决策的有益参考。

对于不向巢中添加衬里材料的次生腔巢鸟类，以前的繁殖事件在巢腔内积累的旧巢材料或有机残留物的存在可能是巢点质量的一个提示。这些材料可能包含有关过去在同种和异种中成功繁殖的信息，并可能提高孵化过程中鸡蛋的隔热性。但是，很少有研究探讨在选择特定的巢穴位置时，是否使用旧巢穴材料作为巢状猛禽的线索。我们进行了一个为期9年的巢箱实验，以测试在制定巢穴选择决策时，来自雌雄同体和旧种的旧巢材料是否可作为欧洲红est（Falco tinnunculus）的信息线索，因为该物种使用巢箱而不添加巢状材料。旧巢材料的存在和入口的大小最好地将欧洲Kestrels所占据的巢箱与未占用的巢箱区分开来。与包含捕食者的真实或模拟巢状材料的巢箱相比，包含特定有机质残留物，人工干叶和分支材料以及大山雀（Parus major）遗留的材料的巢箱以更高的速率重复使用，尤其是包含特定巢状材料的巢箱。在2010年，没有一个巢箱被与前一年相同的带状个体所占据（2009年有10个雌性和2个雄性成群）。欧洲Kestrels优先选择包含旧巢材料的巢箱，而不是空盒子，这与以前的发现一致，即他们在决定定居和繁殖地点时会利用同种异种线索，因为旧巢或有机材料为孵化雌性提供了底物。Kestrels可能能够根据经验或猎物残留的存在来评估与特定巢穴相关的捕食风险。红est在整个繁殖季节重复使用巢箱不能完全归因于philophtry。这项研究提供了证据，表明在欧洲Kestrels中做出巢址选择决策时，旧巢材料可能会被用作信息线索。