Nest decoration as social signals by males and females: greenery and feathers in starling colonies

The expression of elaborated displays provides reliable information to conspecifics about the quality of the signaler. Competition for breeding resources or mates is predicted to affect the expression of signals in both males and females; however, the literature has been typically focused on male behaviors. The spotless starling is an interesting example where both sexes decorate the nest to signal their condition and social status: males add green plants at the beginning of the breeding period, and females place foreign feathers during the incubation period. In this study, we investigate nest decoration by males and females in relation to the intensity of conspecific competition during the breeding period. We distributed nest boxes at either a high (HD) or a low density (LD) and recorded the amount of green plant material added before laying, the number of feathers at hatching, and the breeding productivity under these different density treatments. The amount of green plant material an...精致展示行为的表达，可向同种个体传递有关信号发出者个体品质的可靠信息。针对繁殖资源与配偶的竞争，据推测会影响雌雄个体的信号表达；然而既往相关研究文献通常仅聚焦于雄性行为。无冠椋鸟（Spotless Starling）便是一个极具研究价值的范例：该物种雌雄个体均会通过装饰巢穴来传递自身状态与社会地位的信号——雄性在繁殖初期会添加绿色植物材料，而雌性则会在孵化期置入外来羽毛。本研究旨在探究繁殖期内，无冠椋鸟雌雄个体的巢穴装饰行为与同种竞争强度之间的关联。我们设置了高密度（HD）与低密度（LD）两种巢箱密度处理组，并记录了不同处理组中，产卵前添加的绿色植物材料总量、孵化阶段的羽毛数量，以及繁殖生产力。所添加的绿色植物材料的……