SGER: Use of Small Remote Video Systems to Provide the First Test of the Skutch Hypothesis

食物限制被广泛认为是鸟类生活史特征，特别是窝大小的主要进化驱动因素。半个世纪前，有人认为热带和南半球鸟类的小窝大小是由于巢的捕食限制了父母在筑巢阶段访问巢所造成的(斯库奇假说)。最近广泛的比较研究表明，事实上，鸟巢捕食可能比食物限制代表了更强的鸟类生活史策略的决定因素。然而，斯卡奇假说从未被直接检验过。直接测试将获得巨大的关注，因为这个假说是一个长期存在的，但未经测试的假说，对我们目前对鸟类生活史进化的理解有重大影响。斯库奇假说的直接测试依赖于定量测量父母对鸟巢的探视率。摄像机为获得父母探视率的广泛量化测量提供了一种手段。然而，标准的摄像机系统太大了，而且在一些物种中被发现会影响父母探视率，因为它们在接近巢穴时非常谨慎，因为它们在三脚架上安装了监控巢穴所需的距离(约10米)的大型摄像头。在需要进行这些测试的拉丁美洲，鸟类似乎对摄像机的存在特别敏感，可能是因为那里的捕食性很强。这种偏见严重损害了对斯卡奇假说的检验。马丁博士开发了一种小型远程摄像系统，这种系统可以伪装，甚至连敏感的鸟类似乎都不会理睬它。然而，这个系统还没有在拉丁美洲进行测试，那里的鸟类的反应也还不清楚。马丁博士将在拉丁美洲(阿根廷)对这一系统进行测试，以验证这种方法是否可以提供一种公正的方法来衡量父母探视率，即使是在最敏感的物种中。他将首次同时直接检验斯卡奇假说，方法是检验阿根廷8个物种的父母探视率是否与巢穴捕食率负相关，他已经测量了这些物种的巢穴捕食率。这组物种包括巢捕食率的广泛差异(从24%到76%的巢因被捕食而损失)，从而增加了检验负相关性的统计能力。最终，如果这种方法奏效，它将首次有力地支持或拒绝斯库奇假说，并将提供一种新的方法，迅速推动改变大量研究小组在世界热带和南半球地区开展实地工作的方式。

Food limitation is widely accepted as the primary evolutionary driver of life history traits of birds, particularly clutch size. A half century ago, it was argued that small clutch sizes of tropical and southern hemisphere birds were caused by nest predation constraining parental visits to the nest during the nestling stage (Skutch hypothesis). Recent broad comparative studies suggest that nest predation may, in fact, represent a much stronger determinant of life history strategies of birds than food limitation. However, the Skutch hypothesis has never been directly tested. A direct test will gain enormous attention, because the hypothesis is a longstanding, but untested and has major ramifications for our current understanding of life history evolution in birds.Direct tests of the Skutch Hypothesis depend upon quantitatively measuring parental visitation rates to the nests. Video cameras provide a means for obtaining broad quantitative measures of parental visitation rates. However, standard video camera systems are too large and have been found to influence parental visitation rates in some species because they are cautious about approaching the nest with a large camera setup on a tripod with the distance (ca. 10m) needed to monitor the nest. Birds in Latin America, where these tests need to be made, appear to be particularly sensitive to presence of cameras, possibly because of high predation there. This bias severely compromises tests of the Skutch Hypothesis. Dr. Martin has developed a small remote camera system that is camouflaged and appears to be ignored by even sensitive bird species. However, this system has not been tested in Latin America and responses of birds there are not yet known. Dr. Martin will conduct a test of this system in Latin America (Argentina) to validate whether this approach can provide an unbiased measure of parental visitation rates even among the most sensitive species. He will simultaneously directly test the Skutch Hypothesis for the first time by examining whether parental visitation rates are negatively correlated with nest predation rates across 8 species in Argentina for which he has already measured nest predation. This group of species includes broad variation in nest predation rates (varying from 24 to 76% of nests lost to predation), thereby increasing statistical power for examining a negative correlation. Ultimately, if this approach works, it will provide strong support or rejection of the Skutch Hypothesis for the first time and will provide a new approach that will rapidly catalyze changes in the way a large number of research groups are approaching field work in tropical and southern hemisphere regions of the world.