An experimental study of ecological constraints in the cooperatively breeding acorn woodpecker

橡子啄木鸟（Melanerpes formicivorus）的交配系统是所有脊椎动物中最复杂的，它的群体由多达7只共同繁殖的雄性和3只联合筑巢的雌性组成，它们一起交配（合作一夫多妻制或一夫多妻制），再加上数量不定的非繁殖助手，这些帮手是前几年的后代，它们推迟了分散，留在了它们的出生地。同性共育者几乎都是近亲，要么是兄弟姐妹，要么是父母和后代。该项目将通过实验测试栖息和筑巢洞以及储存橡子的储存设施的作用，这些设施是导致后代延迟分散和同性亲属联盟合作一夫多妻制的生态限制因素。该项目将包括彻底调查现有组别的洞穴和储存设施，并进行实验，在以前未使用的地区提供人工洞穴和储存设施。与对照点相比，实验点的殖民化发生率和比率，以及殖民者的起源和身份，将用于接受或拒绝这些假设。该项目将对生态限制在合作繁殖进化中的作用提供新的见解，不仅包括延迟分散和帮助筑巢，还包括合作一夫多妻制。该项目将特别关注影响这些社会现象的生态制约因素、社会因素（如群体规模和组成）和领土质量变化之间的相互作用。该项目包含了重要的公众宣传，特别是在黑斯廷斯保留区的现场，对游客和学生进行了关于橡子啄木鸟的非正式谈话和示范。后者包括少数族裔、未被充分代表的城市学生，他们在黑斯廷斯保留区度过了一段时间，这是美国国家科学基金会资助的一项主要的k -12计划的一部分。该项目包括一个重要的教育组成部分，即博士后培训和每年最多培训五名直接参与研究的本科生。这项研究涉及到加州橡树林地的工作，这是一个以其生物多样性而闻名的濒危栖息地，并继续进行一个长期项目，该项目有助于我们了解生态系统如何受到人类引起的变化的影响。

The mating system of the acorn woodpecker (Melanerpes formicivorus) is among the most complex of any vertebrate, with groups consisting of a breeding core of up to seven cobreeding males and three joint-nesting females mating together (cooperative polyyamy or polygynandry) in combination with a variable number of nonbreeding helpers that are offspring from prior years and that have delayed dispersal to remain on their natal territory. Cobreeders of the same sex are almost always close relatives, either siblings or parents and offspring. The project will experimentally test the role of roosting and nesting cavities and of storage facilities in which groups store acorns as ecological constraints leading to delayed dispersal by offspring and cooperative polygamy by same-sex coalitions of relatives. The project will involve a thorough survey of cavities and storage facilities of existing groups and an experiment in which artificial cavities and storage facilities will be provided in previously unused areas. The incidence and rate of colonization of experimental sites compared to control sites, together with the origin and identity of colonists, will be used to accept or reject these hypotheses. The project will provide new insights into the role of ecological constraints to the evolution of cooperative breeding, including not only delayed dispersal and helping at the nest but also cooperative polygamy. The project will focus specifically on the interactions between ecological constraints, social factors such as group size and composition, and variation in territory quality as factors influencing these social phenomena.The project encompasses significant public outreach, particularly with respect to informal talks and demonstrations regarding acorn woodpeckers made to visitors and students at the field site, Hastings Reservation. The latter include minority, underrepresented, and urban students spending time at Hastings Reservation as part of a major NSF-funded GK-12 program. The project includes a significant educational component in the form of postdoctoral training and the training of up to five undergraduate students per year who will directly participate in the research. The study involves work in California oak woodland, a threatened habitat known for its biodiversity, and continues a long-term project that contributes to our knowledge of how ecosystems are affected by human-induced changes.