RUI: Hormonal and Body Condition Effects on Natal Dispersal in Birds: Tests of a New Model

9509079 纳塔尔扩散，即从出生地到第一次繁殖地的迁移，几乎发生在所有高等脊椎动物中。 这些迁移对种群调节、交配系统、遗传学和保护生物学有重要意义。本研究的目的是了解鸟类纳塔尔扩散运动的生理生态学。 一种新的扩散模型，激素变化，身体状况和社会刺激之间的相互作用的基础上，将使用圈养和自由生活的鸟类进行测试。 该模型预测，皮质酮，一种激素，已知刺激增加运动和觅食活动，增加扩散之前，由于内源性和外部事件的组合。 这刺激了分散行为背后的运动活动，并且具有足够脂肪储备的青少年将在那时分散。 身体状况不佳的鸟类会延迟分散，但会增加它们的觅食活动。 分散它们的兄弟姐妹将减少侵略和/或对食物的竞争，使剩下的少年能够改善身体状况并分散。 为了测试这个模型，圈养鸟类的激素配置文件将被操纵和随后的活动水平检查有关的时间分散。 第二组实验将研究皮质酮和自由生活的幼鸟的分散运动的时间之间的关系。 这些实验将确定活动水平，身体状况和激素如何相互作用以控制纳塔尔分散。 这项研究将为控制纳塔尔扩散的因素提供重要的新见解。研究结果为进一步研究脊椎动物激素与扩散的关系提供了基础，并对重要管理物种的扩散管理具有一定的应用价值。

9509079 Natal dispersal, the movement from place of birth to location of first breeding, occurs in virtually all higher vertebrates. These movements have important implications for population regulation, mating systems, genetics, and conservation biology. The goal of this project is to understand the physiological ecology of natal dispersal movements in birds. A new model of dispersal, based on interactions among hormonal changes, body condition, and social stimuli, will be tested using both captive and free-living birds. The model predicts that level of corticosterone, a hormone known to stimulate increased locomotor and foraging activity, increases prior to dispersal due to a combination of endogenous and external events. This stimulates the locomotor activity that underlies dispersal behavior, and juveniles with sufficient fat reserves will disperse at that time. Birds in poor body condition will delay dispersing, but will increase their foraging activity. Dispersal of their siblings will reduce aggression and/or competition for food, enabling the remaining juveniles to improve their body condition and disperse. To test this model, hormone profiles of captive birds will be manipulated and their subsequent activity levels examined in relation to timing of dispersal. A second set of experiments will examine the relationship between corticosterone and timing of dispersal movements by free-living juvenile birds. These experiments will determine how activity levels, body condition, and hormones interact to control natal dispersal. This study will provide significant new insight into the factors controlling natal dispersal. The results will provide a basis for future studies of hormones and dispersal in vertebrates, and may be of applied value in managing the dispersal of species whose management is important.