Utilization of Natural Cavities by Secondary Cavity-nesting Birds in Secondary Forest

We studied the nest-site selection of five species of secondary cavity-nesting birds (SCNB):Sturnus cineraceus,Ficedula zanthopygia,Parus major,Parus palustris,and Sitta europaea in secondary forest in the natural protective area of Zuojia,Jilin Province.The results show that the SCNB nest-sites have general characters in selecting horizontal diameter of entrance,vertical diameter of entrance,inner diameter of cavity,vertical depth of cavity and entrance orientations.The cavity entrance orientations of the used cavities are fewer in the orientations from northwest 315° to 360° and southwest 180° to 225° than other orientations,but the situation of the unused cavities are opposite;there exist signifficant differences between the used and unused cavities.The blocked cavities were used by different individuals after reopening.Results show that the natural cavities resource appear to be a limiting factor for SCNB nest-site selecton.