Collaborative Research: Ecology of Migratory Passerine Birds in Breeding and Wintering Areas: Demographic and Experimental Studies

这项研究的目的是确定哪些因素限制或调节在北温带森林繁殖和在新热带地区过冬的候鸟数量。基本问题涉及这些因素在温带夏季繁殖区、新热带冬季繁殖区还是在两个季节都有更重要的作用。通过人口统计学和实验研究，将检验假设，以确定(1)夏季和冬季是否都存在限制，(2)习性占用是否由社会优势(霸权主义)或其他先发制人行为决定，(3)个体在不同栖息地的适应性是否不同，即专制栖息地选择的人口统计学后果，以及(4)哪些生态变量影响栖息地质量，从而影响适应性。重点将放在夏季和冬季生境I之间的不同适宜性上，包括次生林、农田和其他人类改造的生境。研究结果将有助于我们了解这些候鸟物种的种群动态和群落关系，以及影响其种群丰度的因素。这些信息还将有助于制定健全和有效的保护政策。

The objectives of this research are to determine what factors limit or regulate populations of migratory birds that breed in north temperate forests and winter in the Neotropics. the basic questions concerns whether these factors operate more importantly in summer breeding areas at temperate latitudes, in neotropical winter quarters, or during both seasons. Through demographic and experimental studies, hypotheses will be tested to determine (1) if limitation occurs in both summer and winter, (2) if habit occupancy is determined by social dominance (depotism) or other preemptive behavior, (3) if individuals vary in fitness among habitats, that is, the demographic consequences of despotic habitat selection, and (4) what ecological variables affect habitat quality and therefore fitness. Emphasis will be on differential fitness among habitats i both summer and winter, including second-growth forests, agricultural lands, and other human-modified habitats. The results will advance our understanding of the population dynamics and community relations of these migrant bird species, as well as the factors affecting their population abundances. Such information will also contribute to the development of sound and effective conservation policies.