2007年12月至2008年1月，作者在北京小龙门林区进行野外工作，对该地区的冬季鸟类群落进行调查研究。主要结果如下： 1. 在小龙门林区共记录到鸟类32种，隶属4目15科。其中山噪鹛、褐马鸡和贺兰山红尾鸲为中国鸟类特有种，占全国鸟类特有种的4.23%；褐马鸡为国家Ⅰ级重点保护动物，勺鸡和灰林鸮为国家Ⅱ级保护动物。该地区冬季鸟类群落以留鸟为主要成分，占所记录种类总数的75%。 2. 北京小龙门林区的鸟类群落主要由古北界种类组成。旋木雀是该地区鸟类分布的新纪录。 3. 采用Shannon-Weiner物种多样性指数、均匀性指数对北京小龙门林区鸟类的多样性进行了研究。结果表明针阔混交林的鸟类物种数低于落叶阔叶林的鸟类物种数，但是具有较高的鸟类密度，多样性指数和均匀性指数。 4. 对不同海拔的鸟类群落进行研究，表明高海拔地区物种数、生物多样性指数和均匀性指数都比较低，与其他海拔段的相似性较低。 5. 对北京小龙门林区冬季鸟类的栖息高度进行研究，表明树林下层的鸟类物种数和鸟类数量都明显高于其他林层。

The bird community structure was investigated at Xiaolongmen forest area in Beijing during December 2007 to January 2008.The followings are the main results: 1. 32 bird species were recorded, belonging to 4 orders and 15 families, of which 3 species are the endemic species in China, 1 and 2 are listed as the first-grade and second-grade protected animals in China respectively. Most birds recorded are resident birds, with the species number of about 75% of the whole list of the region. 2. The fauna at Xiaolongmen forest area in Beijing belongs to the Palearctic region, with 69% of the birds recorded being the Palearctic group. The Eurasian Treecreeper Certhia familiaris is the new record at this area. 3. The Shannon-Wiener diversity index was been used to analysis the diversities of the bird communities. The research indicated that the species number of the conifer-deciduous mixing forest community is smaller than the species number of the deciduous broad-leaf forest community, but the conifer-deciduous mixing forest community has the higher birds’ richness. The birds’ community between 1330m to 1379m has the least birds’ richness and species number. 4. In winter, the dominant species of the conifer-deciduous mixing forest were Great Tit Parus major、Willow Tit Parus songarus、Eurasian Nuthatch Sitta europaea and Long-tailed Tit Aegithalos caudatus; the dominant species of the deciduous broad-leaf forest were Willow Tit Parus songarus、Eurasian Nuthatch Sitta europaea and Long-tailed Tit Aegithalos caudatus. 5. After analysis the height of the birds perched on, we found that the birds perch on the bottom of forest were relatively more, with the species number and density 59.37% and 39.86% of the total.