Dissertation Research: Adaptive Basis of Delayed Maturation

鸟类鲜艳的颜色一直吸引着鸟类学家的兴趣，但相对较少的研究专门讨论了鲜艳的繁殖羽毛的适应价值。这项研究考察了雄性和雌性紫貂羽毛着色的两个方面：为什么年长的鸟有色彩鲜艳的羽毛，为什么幼鸟有暗淡的亚成体繁殖的羽毛？这将是在自然栖息地对紫貂进行的第一次深入研究。羽毛染色实验将确定羽毛颜色在鸟类保护其筑巢地点免受竞争对手攻击的能力中所起的作用。对巢穴竞争的激烈程度以及幼鸟使用特定的行为策略与年长的鸟类竞争繁殖机会的情况将进行评估。观察亚成体和成体鸟类之间的攻击性互动将确定幼鸟是否因为它们没有威胁的亚成体羽毛而受到较少的攻击性。

The bright coloration of birds has always intrigued ornithologists, yet relatively few studies have specifically addressed the adaptive value of bright breeding plumage. This study examines two aspects of plumage coloration in male and female Purple Martins: why do older birds have a brightly colored plumage, and why do young birds have a dull, subadult breeding plumage? This will be the first intensive study of Purple Martins in a natural habitat. Plumage dyeing experiments will determine the role that plumage color plays in a birds ability to defend its nesting site from competitors. The intensity of competition for nesting cavities and young birds' use of specific behavioral tactics to compete with older birds for opportunities to breed will be evaluated. Observations of aggressive interactions between subadult and adult birds will determine whether young birds are subject to less aggression because of their non-threatening, subadult plumage.