Mechanisms of Habitat Selection in a Specialist and A Generalist Species of Sparrow

相当多的生态学理论指向潜在竞争物种对栖息地的利用，以及这种利用如何随着资源和群落组成的变化而变化。在栖息地反应和栖息地偏好形成的基础上开展的工作要少得多。然而，了解栖息地选择的近似基础对于确定动物物种对观察到的环境变化的反应程度至关重要。本项目的重点是确定影响栖息地选择的因素和两种密切相关的麻雀物种的生态可塑性差异。本文将通过一系列实验来确定宋麻雀（Melospiza melodia）和沼泽麻雀（M. georgiana）固有栖息地反应的差异。宋雀是北美分布最广泛的鸟类之一，出现在各种灌木和沼泽栖息地。它在人类改变的栖息地，如农田和城市中扎根，也经常在小岛屿上殖民。沼泽麻雀是相对专业化的，主要发生在沼泽或类似沼泽的栖息地。在实地观察和实验的基础上，实验室实验的重点将放在麻雀对水、覆盖物和新奇事物的反应上。在野外捕获的未成熟的麻雀中，不同物种之间的反应差异将被揭示，在相同的实验室条件下，人工饲养的麻雀的反应将被测试。由于恐新症提供了一种相对简单的调节动物生态可塑性程度的机制，因此对其的研究将受到重视。实验将包括使用心率遥测技术来测量麻雀对新奇事物的恐惧反应的生理关联的初步工作。研究过程中有待完善的方法可用于脊椎动物生态学的其他各种课题。

Considerable ecological theory is directed towards the use of habitat by potentially competing species and how this might change with varying resources and community composition. Much less work has been conducted on the basis of habitat responses and the formation of habitat preferences. However, understanding the proximate basis of habitat selection is critical in determining how readily animal species can respond to observed environmental changes. The focus of this project is the determination of factors that influence habitat selection and the differences in ecological plasticity found in two closely-related sparrow species. A series of experiments will be done to determine the differences in intrinsic habitat responses in the Song (Melospiza melodia) and Swamp (M. georgiana) sparrows. The Song Sparrow is one of the most widely distributed North American bird species, occuring in a variety of scrub and marsh havitats. It is well established in human-altered habitats such as agricultural fields and cities and is also a frequent colonizer of small islands. The Swamp Sparrow is relatively specialized occuring mainly in marsh or marsh-like habitats. Based on field observations and experiments, the focus of the laboratory experiments will be on the response of sparrows to water, cover, and novelty. Differences in responses between species in wild- caught immatures will be uncovered and the responses of hand- reared sparrows raised under identical laboratory conditions will be tested. Because neophobia provides a relatively simple mechanism for regulating the degree of ecological plasticity in animals, its study will be emphasized. Experiments will include preliminary work on the use of heart-rate telemetry to measure a physiological correlate of fear-responses of sparrows to novelty. Methods to be perfected during the study could be used for a variety of other topics in vertebrate ecology.