Dissertational Improvement: Conspicuous Coloration in Male Northern Cardinals: Possible Benefits Throughout the Year

引人注目的特征，如青蛙或昆虫的发声，鸟类艳丽的羽毛或鲜艳的颜色，都令人困惑，因为它们往往会降低个体的存活率，因为它们的生产或展示成本很高。在这个项目中，雄性北方红雀（Cardinalis Cardinalis）可能全年都有明显的颜色，这是一种全年都有鲜艳羽毛的物种。一项实验将确定颜色是否会影响领地质量和/或雄性与较早繁殖的雌性交配的能力。在繁殖季节之前，雄性的颜色将通过三种方式之一进行控制-增加红色，控制（不改变颜色）和减少红色。如果繁殖季节的颜色影响领地质量和/或繁殖时间，那么在处理组之间将会有显著差异。如果雄性在非繁殖季节的颜色影响了它获得高质量领地和/或更早交配的能力，那么在操纵之前的自然颜色将与这些利益相关。第二个实验将测试红色是否会影响雄性获得食物和栖息地点的质量。同样的三种处理方法将被使用，并将决定觅食效率和雄性在鸟舍中栖息地点的选择。这些结果不仅会引起对性选择感兴趣的行为生物学家和鸟类学家的兴趣，也会引起对昂贵性状进化感兴趣的进化生物学家和理论生物学家的兴趣。

Conspicuous traits, such as vocalization in frogs or insects and showy plumage or bright coloration in birds, are perplexing because often they reduce the survivorship of the individual because they are costly to produce or display. In this project possible year-round benefits to conspicuous coloration in male Northern Cardinals (Cardinalis cardinalis), a species which has bright plumage throughout the year will be studied. One experiment will determine whether coloration influences territory quality and/or a male's ability to pair with an earlier breeding female. The coloration of males just prior to the breeding season will be manipulated in one of three ways - increase red, control (no color change), and decrease red. If coloration during the breeding season influences territory quality and/or timing of breeding, then significant differences among the treatment groups will be expected. If a male's coloration during the non-breeding season affects his ability to obtain a high quality territory and/or an earlier breeding mate, then the natural coloration prior to the manipulation to be correlated with these benefits will be expected. The second experiment will test whether red coloration influences a male's access to food and quality roosting sites. The same three treatments will be used and will determine foraging efficiency and choice of roost site for males in an aviary. These results should be of interest not only to behavioral biologists and ornithologists interested in sexual selection but also to evolutionary and theoretical biologists interested in the evolution of costly traits.