Elaborate ornamental traits are commonly assumed to be honest signals of individual quality, owing to the presumed costs involved in their production and/or maintenance. Such traits are often highly variable, possibly because of condition-dependence and/or high underlying genetic variation, and it has been suggested that their expression should be more sensitive to condition and/or more heritable than non-ornamental traits. Many bird species display colourful plumage with multiple distinct patches of different developmental origins, forming complex colour phenotypes. Despite this complexity, colourful ornaments are often studied in isolation, without comparison to suitable non-ornamental controls. Based on plumage reflectance data collected over 8 years, we assessed the signalling potential of the multidimensional male colour phenotype in a tropical bird: the purple-crowned fairy-wren Malurus coronatus. Specifically, we tested the predictions that the expression of putative ornamental colours (purple and black – the breeding colours – and blue) is (1) more variable, (2) more heritable and (3) more condition-dependent compared to year-round non-ornamental colours (buff-white and brown). Our results show that ornamental colours exhibit greater levels of variability, and some chromatic components of purple and blue colouration appear slightly heritable (h² = 0.19–0.30). However, contrary to predictions of heightened condition-dependence in ornaments, only brightness of the buff-white and brown colouration increased with male body condition, although brightness of the purple colouration was related to male age as expected. Despite partial support for predictions, the lack of consistent patterns illustrates the complexity of visual signals and highlights the need to study colour phenotypes in their entirety.

由于其生产和/或维护涉及的假定成本，精心制作的装饰性特征通常被认为是个体品质的诚实信号。这些性状通常是高度可变的，可能是因为条件依赖性和/或高度潜在的遗传变异，并且有人认为它们的表达应该比非观赏性状对条件更敏感和/或更具遗传性。许多鸟类都展现出五颜六色的羽毛，上面有多个不同发育起源的不同斑块，形成了复杂的颜色表型。尽管存在这种复杂性，但人们常常孤立地研究五颜六色的装饰品，而不与合适的非装饰性对照物进行比较。根据 8 年来收集的羽毛反射率数据，海豚。具体来说，我们测试了以下预测：与全年相比，假定的观赏颜色（紫色和黑色 - 繁殖颜色 - 和蓝色）的表达（1）更多变，（2）更具遗传性和（3）更多条件依赖性非装饰性颜色（浅黄色和棕色）。我们的结果表明，装饰性颜色表现出更大程度的可变性，紫色和蓝色的某些颜色成分似乎具有轻微的遗传性（h² = 0.19–0.30）。然而，与饰品中条件依赖性增强的预测相反，只有浅黄色和棕色的亮度随着男性身体状况的增加而增加，尽管紫色的亮度与预期的男性年龄有关。尽管部分支持预测，但缺乏一致的模式说明了视觉信号的复杂性，并突出了整体研究颜色表型的必要性。