四川南充农田区乌鸫的巢址选择

Nest Site Choice of Turdus merula sowerbyi in Farmland Area of Nanchong,Sichuan

2007年3—5月在四川省南充市近郊农田区域对乌鸫Turdusmerulasowerbyi的巢址选择进行了研究。共调查57个巢址样方，通过主成分分析（PCA）提取到影响乌鸫巢址选择的6个主要因子，其累积贡献率达74．44％，其中乔木因子的贡献率最高，达26．58％。农田区中，乌鸫在4月中旬开始营巢，营巢树平均高度为16．02±2．29m，主要巢树种类是白杨。

From March to May 2007, nest site choice of Turdus merula sowerbyi was studied in the suburb farmland area of Nanchong City, Sichuan Province. In this study, fifty-seven nest sites were sampled with quadrat method, and the principal component analysis （PCA） method was used to abstract the factors which affect the nest site choice of Turdus merula sower- byi. The results showed that six principal components were abstracted, which explained 74.44% of the total variance, and among them, arbor factor was the most important factor, which explained 26.58% of variance. In the farmland area of Nan- chong, Turdus merula sowerbyi built their nests during the middle period of April. The average height of nesting tree was 16. 02 ± 2, 29 m, and the mainly nesting tree was Populus tomentosa.