I am interested in studying variations in the abundance of forest birds in Brazilian Atlantic forest. I study both continuous and fragmented forests, to be able to compare variations in diversity, composition, and trophic structure of birds among different forest types, and also to analyze the effects of forest fragmentation. In a recent paper, I looked at the levels of sensitivity to forest fragmentation for bird species, based on accumulated knowledge of my earlier works. I coordinate a group of research of students in southern Brazil, and we use the same technique for collecting and comparing field information on the abundance of birds. Our technique is based on point count, which depends on acoustic recognition of bird songs; so, a first step is to obtain field recordings of bird songs, a work that began 25 years ago in the year 1983.