四种同域分布洞巢鸟的巢址特征比较

Differentiating nest sites characteristics of four sympatric cavity-nesting birds

洞巢鸟集团是中国东北地区温带次生林内鸟类群落的重要组成部分,对于其巢址特征的比较研究有助于深入了解鸟类群落动态的内在机制。作者于2008年4-7月,对吉林大岗林场4种主要洞巢鸟的巢址特征进行了调查,并从多尺度(巢树、巢址和活动区)比较分析,进而探讨了初级洞巢鸟与次级洞巢鸟的关系。共发现160个繁殖巢,其中初级洞巢鸟58巢,包括大斑啄木鸟(Dendrocopos major)24巢和灰头绿啄木鸟(Picus canus)21巢;次级洞巢鸟102巢,包括白眉姬鹟(Ficedula zanthopygia)38巢和普通?(Sitta europaea)45巢。初级洞巢鸟对巢树无显著选择性,而次级洞巢鸟对巢树有显著选择性,以白皮柳(Salix pierrotii)为主。灰头绿啄木鸟的洞口主要朝南,而其他3种洞巢鸟对洞口朝向没有显著的选择性。初级洞巢鸟巢址特征的差异主要表现在巢树和巢址尺度上,而次级洞巢鸟在3个尺度上均有显著差异。逻辑斯蒂回归分析表明,区分大斑啄木鸟和灰头绿啄木鸟洞巢的关键因子为洞口直径和洞巢内径,即洞巢的大小;区分白眉姬鹟和普通?洞巢的关键因子为巢树树冠高度和洞口深度。也就是说,初级洞巢鸟之间以及次级洞巢鸟之间巢址特征的最主要差异均在巢树尺度上。判别分析表明,普通?倾向于选择灰头绿啄木鸟提供的洞巢,而白眉姬鹟偏好于大斑啄木鸟提供的洞巢。由于啄木鸟所凿洞巢的大小不同,导致了次级洞巢鸟对其巢址的差异性选择。因此,洞巢的大小是影响同域分布的洞巢鸟巢址利用的最重要因素。

Diverse group of cavity-nesting birds inhabit secondary forests of northeastern China, accounting for about one-third of breeding avian species. We examined differences in nest-site characteristics among four cavity-nesting birds, including two cavity excavators （i.e., great spotted woodpecker [Dendrocopos major] and grey-headed woodpecker [Picus canus]） and two secondary cavity-nesters （i.e., yellow-rumped flycatcher [Ficedula zanthopygia] and Eurasian nuthatch [Sirra europaea]） in Dagang Forestry Farm, Jilin Province, China. We detected total 160 active hole nests in the breeding season of 2008, including 58 nests of cavity excavators and 102 of secondary cavity-nesters. Secondary cavity-nesters tend to prefer Salix pierotii for nestingtrees, but the excavators not. Picus canus used south-facing cavities, which may have been due to thermal advantages. Nest tree and nest-site quadrat characteristics were different between the two excavator species. Specifically, there were significant differences in the entrance diameter and cavity inner diameter between the nest sites of Dendrocopos major and Picus canus, and the entrance length and canopy height of nest tree between Ficedula zanthopygia and Sitta europaea. The characteristics at the scale of nest tree were important for distinguishing nest sites for cavity excavators as well as secondary cavity-nesters. Discriminant analyses illustrated that Ficedula zanthopygia and Sitta europaea used cavities excavated by Dendrocopos major and Picus canus, respectively. Differences in size of nesting holes excavated by different woodpeckers could affect the usage of nest sites by secondary cavity-nesters, which may have an impact on avian cornmunity structure in secondary forests.