A new theory of clutch size evolution: Consequences of morphology at fledging on mobility and survival interacting with parental energy expenditure (FMR)

父母应该付出多大的努力来抚养后代，这种努力如何影响父母试图抚养的后代的数量和存活率？ 这些问题已经吸引了科学家们超过世纪，并对野生动物的种群动态有重大影响。 这些问题在鸣禽中得到了强调，因为不同物种在父母试图抚养的幼鸟数量上差异很大。即使在同一栖息地繁殖的物种之间，例如将进行工作的亚利桑那州高海拔河岸栖息地，物种在它们试图养育的后代数量上也有很大差异。 例如，在该栖息地的绿尾towee通常产3或4个蛋，红脸莺产4或5个蛋，而山地山雀可能产8个蛋。 提出了一种新的理论来解释这种基于后代和父母死亡风险的变化，这笔赠款将资助新理论的测试。 不同物种的幼鸟被捕食者吃掉的风险不同，towhee或莺的开口杯巢被捕食的风险很高，而山雀的腔巢被捕食的风险很低。 这些捕食风险的差异影响了幼鸟在巢中停留的时间;像towhee和莺这样的物种在孵化后8到11天离开它们的危险巢，而山雀在孵化后20到22天才离开它们的安全巢。 因此，towhee和莺年轻时不能飞，当他们离开他们的巢，而山雀是完全飞行能力时，他们离开。 当它们离开巢穴时，年轻人发育状态的这些差异也可能影响它们开始进食的速度，山雀可能在离开巢穴后的几天内自行进食，而towhee可能需要3周才能发展这种能力。 潜在的，towhee父母必须更加努力地为每个年轻人提供所有的食物，而山雀几乎立即开始获得一些自己的食物，并可以跟随父母减少旅行。 父母愿意工作的程度因物种而异，这取决于它们在年周期中的死亡风险。 总之，这些影响可以解释为什么物种在他们试图提高年轻的数量不同，并有物种的种群动态的关键后果。 拟议的工作将使用观察和实验的方法来测试这些hypothesis.The羽翼未丰的时期（后后代离开巢）是一个关键时期的人口，但种间的生存变化是未知的和文件将有助于了解人口的脆弱性不断变化的环境条件。鉴于鸟类对社会的经济和美学重要性，这种保护知识是重要的。本项目将培养三名论文研究的研究生。每年，1名技术人员和6名本科生将接受现场技术和科学行为方面的培训，以及来自各学科（生物学内外）的8名本科生，以转录父母行为的视频。后者提供外联活动，让不同的学生参与科学原理。学生将通过讨论会，将被用来教正在进行的工作的科学原理进行教育。为物色合适人选，我们将采用广泛的广告宣传方法，进一步加强我们可招聘的社会及文化群体的多元化。最后，鸟巢提供了丰富的视频资源，以展示物种之间在社会互动中的差异，以及捕食事件的有趣视频。研究人员开始获得简短的高清视频，以开发一个关于父母和后代行为以及捕食事件的教育系列，并将其放在YouTube上进行公众宣传。 PBS Nature正在拍摄一部关于鸟巢建筑和鸟类家庭生活的纪录片，其中将包括焦点现场的镜头，以进一步增加公众宣传。

How hard should parents work to raise offspring, and how does this work effort influence the number and survival of offspring that parents attempt to raise? These are questions that have intrigued scientists for more than a century, and have major implications for population dynamics of wild animals. These questions have been highlighted among songbirds because species vary extensively in the number of young that parents attempt to raise. Even among species that breed in the same habitat, such as high elevation riparian habitat in Arizona where work will be conducted, species vary extensively in the number of offspring they attempt to raise. For example, a green-tailed towhee in that habitat typically lays 3 or 4 eggs, a red-faced warbler lays 4 or 5 eggs, while a mountain chickadee may lay 8 eggs. A new theory to explain this variation based on risk of mortality to offspring and parents is proposed and this grant will fund tests of the new theory. Species differ in the risk of their young being eaten by predators, with the open cup nests of the towhee or warbler experiencing high predation, while the cavity nests of chickadees experience very low risk of predation. These differences in predation risk affect how long the young stay in the nest; species like the towhee and warbler leave their risky nest 8 to 11 days after hatch, while chickadees do not leave their safe cavity nest until 20 to 22 days after hatch. As a result, the towhee and warbler young cannot fly when they leave their nest, while the chickadees are fully flight capable when they leave. These differences in developmental state of the young when they leave the nest also potentially affect how quickly they start feeding themselves, with the chickadees potentially feeding themselves within a few days after leaving the nest, while the towhee may take 3 weeks to develop this ability. Potentially, towhee parents must work much harder for each young to provide all their food compared with the chickadee where young almost immediately start obtaining some of their own food and can follow parents to reduce their travel. The extent to which parents are willing to work differs among species depending on their risk of mortality over their annual cycle. Taken together, these effects may explain why species differ in the number of young they attempt to raise, and has critical consequences for population dynamics of species. The proposed work will use observational and experimental approaches to testing these hypotheses.The fledgling period (after offspring leave the nest) is a critical period for demography, but interspecific variation in survival is unknown and documentation will aid understanding of population vulnerabilities to changing environmental conditions. Given the documented economic and aesthetic importance of birding to society, this conservation knowledge is important. Three graduate students whose thesis research will be supported by this project will be trained. Each year, 1 technician and 6 undergraduates will be trained in field techniques and the conduct of science, as well as 8 undergraduates from across disciplines (in and outside of biology) to transcribe videos of parental behaviors. The latter provides outreach to engage diverse students in scientific principles. Students will be educated through discussion sessions that will be used to teach the scientific principles for the work being conducted. To identify possible recruits, we will use broad advertising approaches to further enhance the diversity of social and cultural groups from which we can recruit. Finally, nests provide a rich source of video opportunities to demonstrate differences among species in social interactions, as well as intriguing videos of predation events. The researcher started obtaining short, high definition videos to develop an educational series on parental and offspring behaviors and predation events to put on YouTube for public outreach. PBS Nature is filming a documentary on nest architecture and avian family life that will include footage at the focal field site to further increase public outreach.