Effects of breeding density on the behaviour and reproductive success of cavity nesting birds

繁殖密度对空巢鸟类行为和繁殖成功率的影响

• 批准号: RGPIN-2016-03742
• 负责人: Wiebe, Karen
• 金额: $ 2.04万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=614594
• 关键词: Effects; breeding; density; behaviour; reproductive

Many species of birds and mammals use tree holes for nesting. Secondary cavity users compete for nesting holes created by excavators such as woodpeckers which are the called the primary cavity excavators. The types of resources (tree substrates) and characteristics of cavities used by different species of cavity-nesters have been well described. However, there is a poor understanding of how intra- and inter-specific competition for nest sites influence the settlement patterns, nest spacing on the landscape, and the reproductive success of cavity-nesting birds in forests. Studying the consequences of breeding density is important because many habitats are becoming more fragmented, for example as a result of forest harvesting. As a result, densities may increase in the remaining habitat patches, and birds may be forced to interact more with one another. The main objective of my research is to study the effects of breeding density and competition for nesting sites on the behaviour and reproductive success of cavity-nesting birds. I will use data from a diverse community of cavity-nesters using natural tree holes at Riske Creek, B.C to search for correlations between nest spacing and reproductive success. However, I will focus on field experiments involving two common cavity-nesting species: Mountain Bluebirds and Tree Swallows which compete with each other for nesting sites and readily use nest boxes. By manipulating nest density, I will study whether there are behavioural and physiological trade-offs between defending a nest site and foraging, and ultimately reproductive success. High densities of potential nest competitors may increase reproductive costs but there may also be benefits such as communal mobbing of predators. Using experimental manipulations of nest density and presentation of predators (model owls and squirrels) at the nest boxes of swallow and bluebird pairs, I will test whether neighbours of the same, or of other species, contribute to group mobbing. Specifically, I will test the hypothesis that clumped nests are safer from predators than isolated nests. In sum, my research will increase our understanding of reproductive challenges and benefits experienced by birds in a landscape increasingly affected by fragmentation, and may aid in developing forest harvest patterns that reduce the stress for breeding birds.

许多种类的鸟类和哺乳动物利用树洞筑巢。次级洞穴使用者争夺由诸如啄木鸟之类的挖掘机（被称为初级洞穴挖掘机）创造的筑巢洞。对不同种类的洞巢虫所利用的资源（树体）类型和洞巢特征进行了详细的描述。然而，有一个贫穷的了解如何内部和种间的巢址竞争影响的解决方案，巢间距的景观，以及在森林中的洞穴筑巢鸟类的繁殖成功。研究繁殖密度的后果很重要，因为许多生境正变得更加支离破碎，例如森林采伐。因此，剩余栖息地斑块的密度可能会增加，鸟类可能会被迫更多地相互交流。 我的研究的主要目的是研究繁殖密度和筑巢地点的竞争对洞穴筑巢鸟类的行为和繁殖成功率的影响。我将使用来自一个不同的社区的洞穴巢使用天然树洞在Riske溪，不列颠哥伦比亚省的数据，以寻找巢间距和繁殖成功之间的相关性。然而，我将专注于两个常见的洞穴筑巢物种的实地实验：山蓝知更鸟和树燕，它们相互竞争筑巢地点，并随时使用巢箱。通过操纵巢密度，我将研究是否有行为和生理之间的权衡捍卫巢址和觅食，并最终繁殖成功。 高密度的潜在巢穴竞争者可能会增加繁殖成本，但也可能有好处，如捕食者的社区围攻。使用实验操作的巢密度和介绍的捕食者（模型猫头鹰和松鼠）在巢箱的燕子和蓝鸟对，我将测试是否邻居相同，或其他物种，有助于群体围攻。具体来说，我将测试的假设，丛生的巢比孤立的巢更安全的掠食者。总之，我的研究将增加我们对鸟类在日益受到碎片化影响的景观中所经历的生殖挑战和益处的理解，并可能有助于开发森林收获模式，以减少繁殖鸟类的压力。