By survey of 21 quadrats and 118 sample lines of Passeriformes birds on the south slope of Qinling Mountains,including the counties of Fengxian,Taibai,Liuba,Yangxian,Lueyang,Foping and Chenggu,28 species in 13 families were recorded. Of which 7 species were found no more than 10 birds for each,accounting for 25% of all birds records in this study; for 6 species,each had the individuals between 10 and 100 with21. 43% proportion; and 15 species were observed more than 100 birds of each,with 53. 57% of the tot...