Adaptive nest site choice by birds

在繁殖的早期，鸟类必须考虑栖息地的各个方面，如觅食区、捕食者和植被覆盖的邻近程度，决定在哪里繁殖。因为巢穴栖息地可能对繁殖成功有深远的影响，所以人们对解开这些决定的基础非常感兴趣。据推测，遭受筑巢失败的鸟类会学习并适应性地分散到更好的巢栖息地。筑巢失败更多地归因于捕食，而不是任何其他原因。因此，预计父母将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前面框架的各个方面做出新的贡献，重点是评估相对于以前的巢成功对巢栖息地的适应性选择，以及父母对捕食者的防御。我还将挖掘我15年来在树燕子中繁殖的数据集，在这些数据集中，我已经操纵了巢栖息地，使我能够通过实验测试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，我将评估行为密码的策略；繁殖成对的鸟可以通过同步巢穴访问来限制捕食者观察觅食的机会，从而提高巢穴位置的密码。此外，如果父母鸟的接近和离开矢量明显结束于特定位置，捕食者可能更有可能栖息在筑巢地点。因此，接近鸟巢的父母应该离开一个相差180度的方向；这样，捕食者可能会得出结论，一只鸟只是在前往最终目的地的途中暂时停留。我提出并发展了编舞假设，即预测双亲的取食同步性和协调的接近/离开向量，以减少捕食者对繁殖地点的检测。例如，该假说对捕食者群落、觅食频率、孵化价值、亲鸟在一起繁殖的时间，以及前述因素对编舞的影响等做出了大量的原始预测。对编舞假说的初步测试将使用树燕进行；后续测试将扩展到其他物种。我的研究将对其他致力于达尔文适应性这些关键方面的人产生广泛的兴趣；我独特而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因素进行尖端研究。加拿大人通过联邦政府提供的资金使我能够培训学生，这是我研究项目中最有回报的部分之一。我的学生作为成熟的科学家离开，他们揭示了鸟类生物学的新方面，这些方面可能会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.