Fitness Consequences of Avian Coloniality

9613638 棕色 该项目旨在了解动物群居的原因。 许多不同的生物体，包括人类，表现出不同程度的群体生活：一些动物生活在小群体中或单独生活，而同一种群中的其他动物可能生活在巨大的群体中。 要理解为什么有些人喜欢生活在大群体中而另一些人则喜欢生活在小群体中，需要了解这种选择的生殖后果。 某些动物以何种方式受益于一种规模的群体，而另一些动物则明显受益于另一种规模的群体？ 这项研究解决了这个问题，该研究重点关注一种群体繁殖的鸟类——悬崖燕子（_Hirundopyrrhonota_），这种鸟类在北美西部大部分地区的陡峭悬崖和峡谷两侧以及桥梁和建筑物的屋檐下繁殖。 目标是确定不同的鸟类如何在不同大小的筑巢群中进行分类以及基于什么分类；是否存在最适合所有鸟类的单一群体规模（繁殖成功率最高）；燕子对特定大小筑巢群的偏好是否是基于基因的，因此是从其父母那里继承的；以及如果筑巢群的大小发生变化，鸟类的筑巢成功率会受到怎样的影响。 该研究主要使用涉及鸟类环志的标记重新捕获方法：鸟类在特定地点进行环志，然后通过在该地点或以后几年在其他地点重新捕获它们来确定它们随后的活动和寿命。 这项研究建立在过去 15 年对悬崖燕子种群的研究基础上。 该项目将进一步了解为什么动物群体规模在自然界中存在差异。 群体规模影响动物行为的许多方面：例如，疾病的传播、对食物等资源的竞争程度、交配策略的类型以及个体之间的合作和利他主义程度都在很大程度上受到社会群体规模的影响。 如果我们首先知道是什么导致群体规模不同，并且知道不同的群体是否由不同类型的个体组成，我们就能更好地理解群体生活的这些重要后果。 悬崖燕子提供了一个经过充分研究的动物模型，其社会行为与其他社会物种的社会行为相似，并且它将深入了解控制多种生物体群体形成的基本过程。

9613638 BROWN This project seeks to understand why animals live in groups. Many different organisms, including humans, show different degrees of group-living: some animals live in tiny groups or solitarily, whereas others in the same population may reside in enormous colonies. To understand why some individuals prefer living in large groups and others in small groups requires knowing the reproductive consequences of such choices. In what way do certain animals benefit from groups of one size while others apparently benefit from groups of another size? This question is addressed in this research, which focuses on a colonially breeding bird, the cliff swallow (_Hirundo pyrrhonota_), that breeds on the sides of steep cliffs and canyons and underneath the eaves of bridges and buildings throughout much of western North America. The objectives are to determine how different birds sort themselves among different sized nesting colonies and on what basis; whether there is a single colony size that is best for all birds (where reproductive success is greatest); whether a swallow's preference for a particular sized nesting colony is genetically based and thus inherited from its parents; and how the birds' nesting success is affected if their nesting colony is changed in size. The research uses primarily mark-recapture methods that involve bird banding: birds are banded at a particular site and their subsequent activity and lifespan is determined by recatching them at that site or others in later years. This study builds on 15 years of past work on this cliff swallow population. This project will further our understanding of why animal group sizes vary in nature. Group size affects many aspects of animal behavior: for example, the spread of disease, extent of competition for resources such as food, type of mating strategy, and extent of cooperation and altruism among individuals are all influenced heavily by the size of a social group. We can better understand these important conseque nces of group life if we know what causes groups to vary in size in the first place and if we know whether different groups are composed of different kinds of individuals. The cliff swallow provides a well-studied animal model whose social behavior parallels that of other social species, and it will yield insight into fundamental processes that govern group formation in many kinds of organisms.