Adaptive nest site choice by birds

在繁殖的早期，鸟类必须决定在哪里繁殖，考虑到栖息地的各个方面，如靠近觅食区、捕食者和植被覆盖。由于筑巢环境对繁殖成功有着深远的影响，人们对解开这些决定的基础有着浓厚的兴趣。遭受筑巢失败的鸟类被认为能够适应地学习和分散到更好的筑巢栖息地。巢的失败往往归咎于捕食而不是其他原因。因此，预计父母会在隐藏巢穴以躲避捕食者的策略上投入大量资金。我的研究计划将在严格测试上述框架的各个方面做出新的贡献，重点是评估相对于以前的筑巢成功的筑巢栖息地的适应性选择，以及父母的反捕食者防御。我还将挖掘我15年来关于树燕繁殖的数据集，在这些数据集中，我操纵了鸟巢栖息地，使我能够通过实验来测试鸟巢栖息地对繁殖成功的影响。利用重新捕获的数据，我将测试成虫是否会在连续的繁殖尝试中适应性地选择更好的筑巢地点。接下来，我将评估行为隐密的策略；配对繁殖的鸟类可以通过同步访巢来改善巢址的隐密性，从而限制捕食者观察喂养的机会。此外，如果父母鸟的接近和离开向量明确地结束在一个特定的位置，捕食者可能更有可能回到巢的位置。因此，接近巢穴的父母应该在180度的方向上离开；通过这种方式，捕食者可能会得出结论，这只鸟只是在飞往最终目的地的途中暂时停了下来。我提出并发展了“舞蹈假说”，该假说预测了捕食同步和父母的协调接近/离开向量，以减少捕食者对繁殖地的发现。这一假说提出了大量的原始预测，例如，关于捕食者群体、喂养频率、育雏价值、父母鸟类在一起繁殖的时间，以及上述因素对舞蹈编排的影响。编舞假说的初步测试将使用树燕；随后的试验将扩展到其他物种。我的研究将对其他研究达尔文适应性的关键方面的人产生广泛的兴趣；我的独特和令人兴奋的预测可以在各种系统中进行测试。******我的主要研究目标是对构成鸟类繁殖成功和生存的重要贡献者的因素进行前沿研究。加拿大通过联邦政府提供的资金使我能够培训学生，这是我的研究项目中最有价值的部分之一。我的学生离开时已经是成熟的科学家，他们已经揭开了鸟类生物学的新方面，可以对保护产生重要的积极影响。

Early in the imperative of reproduction, birds must decide where to breed, taking into account aspects of habitat such as proximity of foraging areas, predators, and vegetative cover. Because nest habitat can have profound influences on reproductive success, there is intense interest in unravelling bases for these decisions. Birds suffering nest failure are presumed to learn and disperse adaptively to better nest habitats. Nest failure is more often ascribed to predation than to any other cause. Accordingly, parents are predicted to invest significantly in strategies to conceal nests from predators. My research program will make novel contributions in rigorously testing aspects of the preceding framework, focusing on evaluating adaptive choices of nest habitat relative to previous nest success, and on parents' anti-predator defences. I will also mine my 15-year data set on reproduction in tree swallows wherein I have manipulated nest habitat to enable me to test experimentally for effects of nest habitat on reproductive success. Using recapture data, I will test whether adults adaptively choose better nest sites in successive reproductive attempts. Next, I will evaluate strategies of behavioral crypsis; breeding pairs of birds can improve crypsis of nest sites by synchronizing nest visits to limit opportunities for predators to observe feedings. In addition, predators may be more likely to home in on nest locations if parent birds' approach and departure vectors clearly end at a particular location. Thus, parents that approach nests should depart in a direction that differs by 180 degrees; in this way, a predator may conclude that a bird merely stopped temporarily en route to a final destination. I propose and develop the Choreography Hypothesis that predicts both feeding synchrony and coordinated approach/departure vectors of parents to reduce detection of breeding sites by predators. The hypothesis makes a wealth of original predictions with respect to, for example, predator communities, frequency of feeding, brood value, and how long parent birds have bred together, and influences of the preceding on choreography. Initial testing of the Choreography Hypothesis will be done using tree swallows; subsequent tests will be extended to other species. My research will have broad interest for others working on these critical aspects of Darwinian fitness; my unique and exciting predictions can be tested in a variety of systems. ******My primary research objectives are to conduct cutting edge research on factors that constitute significant contributors to avian reproductive success and survival. Funding from Canadians through the federal government enables me to train students, one of the most rewarding parts of my research program. My students leave as mature scientists who have unravelled novel aspects of birds' biology that can have important positive conservation impacts.