Dissertational Improvement: Ecological Pressures Selecting for Dietary Plasticity During Migration in Two Neotropical Migratory Passerine Genera

论文改进：两个新热带候鸟雀属迁徙过程中生态压力对食物可塑性的选择

• 批准号: 9411650
• 负责人: Douglass Morse
• 金额: $ 1.11万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-07-15 至 1996-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9411650&HistoricalAwards=false
• 关键词: Dissertational; Improvement; Ecological; Pressures; Selecting

9411650 Morse The decline of many populations of Neotropical migratory songbirds has triggered much research over the last decade into the biology of these species on their temperate breeding grounds and their tropical wintering areas. The interim migration period has received much less attention, despite the extreme energetic demands and the very divergent behavior of migrants during this transient period. During migration, many songbirds diversify their breeding-season behaviors to select different habitats, use more foraging behaviors, and feed on more varied diet types than at other times of the year. The ecological factors behind the evolution of such behavioral plasticity and the ecological and conservation implications these divergent behaviors remain speculative. The proposed research will investigate these questions in one aspect of behavioral diversification in autumn migrating songbirds - the shift in diet from eating insects to one of eating fruit. Preliminary research on Block Island, Rhode Island suggests that unpredictability in resource abundance at migratory stopover sites and increased energy intake on expanded diets during the demanding migration period have led to behavioral plasticity in songbirds. This research will be furthered with continued monitoring of insect and fruit abundance at stopover sites to monitor different degrees of predictability of the two resources during Autumn, 1994 and 1995. Furthermore, migrants will be fed experimental diets with varying degrees of fruit to determine the extent they can fatten on expanded diets, thus testing the hypothesis that diversification of ingested food types has resulted from selection to maximize energy intake during migration. Finally, experiments will allow evaluation (through doubly-labeled water techniques) of the amount of energy saved by migrant birds in feeding on diverse diets. These techniques allow estimation of the energy expenditure of birds which can be follow ed under situations where birds have monotypic and diverse diets available to them. These studies will provide insight into the evolutionary pressures for behavioral plasticity as well as important information about the biology of migrating songbirds. This in turn will allow better conservation decisions to be made regarding these declining populations. ***

9411650莫尔斯，许多新热带候鸟种群的减少在过去十年里引发了对这些物种在其温带繁殖地和热带越冬区的生物学的大量研究。临时移民时期受到的关注要少得多，尽管移民在这一过渡时期有着极端的精力需求和非常不同的行为。在迁徙过程中，许多鸣禽会将繁殖季节的行为多样化，以选择不同的栖息地，使用更多的觅食行为，并与一年中的其他时间相比，捕食更多样化的饮食类型。这种行为可塑性进化背后的生态因素以及这些不同行为的生态和保护含义仍然是推测的。这项拟议的研究将从秋季迁徙鸣禽行为多样化的一个方面来研究这些问题--饮食从吃昆虫转向吃水果。对罗德岛布洛克的初步研究表明，迁徙中途停留地点的资源丰富程度的不可预测性，以及在要求苛刻的迁徙期间扩大饮食的能量摄入增加，导致鸣禽的行为可塑性。这项研究将继续监测中途停留地点的昆虫和水果数量，以监测这两种资源在1994年和1995年秋季的不同程度的可预测性。此外，候鸟将被喂以不同程度的水果实验饮食，以确定他们在扩大饮食中可以增肥的程度，从而检验这样一种假设，即摄取的食物类型的多样化是为了在迁徙期间最大限度地增加能量摄入而进行的选择。最后，实验将允许评估(通过双标记水技术)候鸟在摄取不同食物时节省的能量。这些技术可以估计鸟类的能量消耗，在鸟类有单一和多样化的食物可供选择的情况下可以跟踪这种情况。这些研究将提供对行为可塑性的进化压力的洞察，以及关于候鸟生物学的重要信息。这反过来将使人们能够针对这些不断下降的人口做出更好的保护决定。***