内蒙古达赉湖西岸地区大鵟巢穴特征和巢址选择

2010年和2011年3月-6月,对内蒙古达赉湖国家级保护区达赉湖西岸地区大鵟(Buteo hemilasius)的巢穴结构和巢址选择因子进行了调查研究.采用野外观察和样方法定位了13个大鵟巢址,并对巢址样方的20个生态因子进行测量,运用主成分分析法对影响大鵟巢址选择的主要因子进行了分析.测量显示,大鵟巢穴的基本结构特征为:外径(94.7+4.2) cm;巢高度(46.1±2.7) cm;内径(24.8±1.5)cm;巢深(14.0±+0.9)cm.生境因子分析结果表明,达赉湖西岸地区大鵟的巢集中分布在湖岸或水塘附近的悬崖,营巢点坡度为15°-45°之间的阳坡或半阳坡；隐蔽度高于20％；草本密度大于5株/m2;植被均高大于30cm;巢距悬崖上部距离2-5m；距水源l00m以内；距居民点距离大于lkm;距草原道路的距离大于0.5km;而对于物种丰富度没有特殊要求.主成分分析显示,影响大鵟巢址选择的主要因子有3个,依次为:隐蔽性因子(主要包括巢址区域的植物特征和地形特征)、干扰因子和食物因子.各主成分中,相对系数绝对值最高的变量依次是:植被盖度、距居民点距离、巢的高度和距草原道路距离.

The research on Buteo hemilasius nest-site selection on the west bank of Dalai Lake in Dalai Lake Natural Reserve

From March to July, 2010 and 2011, the nest structure and nest-site selection of Upland Buzzard (Buteo hemilasius) were investigated on the west bank of Dalai Lake in Dalai Lake Natural Reserve,Inner Mongolia. Field observation found that the earliest activity of Upland Buzzard appeared on around March 25;egg-laying began in the middle and late April and the breeding ended at about the beginning of July. By the direct observation and plot sampling method in the field,we positioned thirteen nests, measured twenty ecological factors of this thirteen samples. The Cluster Analysis based on the Euclidean distance was used to assess all twenty ecological factors. Through a rough measurement, the Upland Buzzard's nest is characterized in that-the outer diameter is (94.7±4.2)cm while the inner diameter (24.8±1.5)cm; nest deep is (14.0±0.9)cm and nest height is (46.1±2.7)cm.The results of ecological factors analysis indicated that in West bank of Dalai Lake,Upland Buzzard's nests are mainly centralized distributed in the lake bank or blisters near the cliff;nesting sites are mainly middle or higher slope position;the gradient ranged from 15°-45° on sunny slopes and semi-sunny slopes;the nest-sites have high-level concealment, the density of herbaceous is higher than 5 strains/m²;average high of vegetation is higher than 30cm; distance of nests to cliff upper is between 2-5 m; the distance to water resource is within 100m; distance to settlements is more than 1 km;distance to the prairie path is more than 0.5km while has no special requirements of species richness. The principal components analysis shows that there are three most important factors of Upland Buzzard nest-site selection as follows, the covert factors (including nest-site area plant characteristics and topographic features), human interference factors and food factors. In the main compositions, Vegetation coverage, distance to settlements,nest height and distance to prairie paths have the highest relative coefficient absolute value.