Bird diversity in summer and autumn on the north slope of Taibaishan Mountain

In 2006,a bird survey was performed on the north slope of Taibaishan Mountain,the summit of the Qinling range in the center of China,during two time periods:from May to July in the summer and from September to October in the autumn.Based on elevation and vegetation,six types of habitat were categorized,and characteristic sample plots were selected within each habitat type.The birds in each sample plot were counted using a line transact methodology.The absolute density of species was calculated and ranked based on the absolute abundance and estimated area,and dominant and common avian species in each habitat type were defined according to ranks within species density.We encountered 144 bird species total,including 102 residents,41 summer breeders and 1 winter migrant.Species richness,abundance and the constitution of dominant and common species showed significant variation across the six types of habitat.Even within given habitat types,the diversity of bird species and the constitution of dominant and common species exhibited obvious seasonal change.The highest and lowest total densities were found in cropland habitat and alpine meadow habitat,respectively.A significant seasonal difference in diet of birds was only found in cropland habitat.When correlated to elevation,the highest bird species richness was found in those habitats occurring primarily at mid-elevation.In general,our results indicate a complex,and habitat specific,distribution of avian populations and obvious change on the north slope of Taibaishan Mountain.