芦苇湿地共域繁殖的4种雀形目鸟类的巢址选择和繁殖成效比较

鸟类的巢址选择对其繁殖成效具有重要影响。对共域繁殖的不同鸟种繁殖策略的比较,有助于理解鸟类生活史对策的进化。为此,我们在河北永年洼湿地对利用芦苇繁殖的4种鸟类即东方大苇莺(Acrocephalus orientalis)、钝翅苇莺(Acrocephalus concinens)、震旦鸦雀(Paradoxornis heudei)和棕头鸦雀(Sinosuthora webbiana)的巢址选择和繁殖成效进行了比较。结果表明,尽管四种鸟类开始繁殖的时间明显不同,但其巢址、巢型和巢结构均类似,并在同一研究地内镶嵌分布,仅在巢离水面的高度、筑巢芦苇的高度和巢址样方内的芦苇密度三个变量参数上存在显著差异。四种鸟类在两个繁殖季的繁殖成效均较低,其中东方大苇莺为34.5%(86/249),钝翅苇莺为35.3%(6/17),震旦鸦雀为38.5%(15/39),棕头鸦雀为40.9%(9/22)。影响繁殖成效的主要生态因子包括巢捕食和恶劣天气如暴雨和强风暴,而被大杜鹃(Cuculuscanorus)寄生则是导致东方大苇莺繁殖成功率较低的主要原因。我们的研究表明,同域繁殖的鸟类可以通过繁殖时间的错峰和巢址的分化等而实现共存。

Nest-site Choice and Breeding Success among Four Sympatric Species of Passerine Birds in a Reedbed-dominated Wetland

The efficacy of nest-site choice ultimately determines the breeding success of birds. Comparisons of the reproductive strategies of various bird species which inhabit the same habitat may provide insights on the evolution of the diverse life-history strategies in birds. In this study, nest-site choice and breeding success of four species of passerine birds that rely on reeds for reproduction were investigated in a wetland in Hebei, China. The four species were the Oriental reed warbler(Acrocephalus orientalis)(ORW), the blunt-winged warbler(Acrocephalus concinens)(BW), the reed parrotbill(Paradoxornis heudei)(RP), and the vinous-throated parrotbill(Sinosuthora webbiana)(VP). Our results showed that breeding nests of the four species were distributed in a mosaic pattern within the same habitat, with similar nest shapes/structures and nest-sites in the reeds. The only characteristics which differed significantly among the species were nest height above the water surface, height of reeds where nests were placed, and density of reeds around the nest site. In addition, the starting time of reproduction clearly differed for the four species. The breeding success rates of the four species were 34.5%(86/249) for ORW, 35.3%(6/17) for BW, 38.5%(15/39) for RP, and 40.9%(9/22) for VP in the two study years. The main factors affecting the breeding success were nest predation and poor weather conditions, like heavy rainstorms and wind, while nest parasitism by the common cuckoo(Cuculus canorus) represented an important factor for breeding failure only in the Oriental reed warbler. Our study demonstrated that these four sympatric species of passerine birds inhabiting the same wetland exhibit differences in terms of nest-site choice and breeding phenology.