Most of the sounds are of birds, but he also has recordings of insects, amphibians and mammals. It is one of the most valuable things I do. Once Benson has recorded sounds in the field, he returns to his sound lab and analyzes the raw data. In playback experiments the sounds are used to see how species react to certain sounds. In some instances we are looking for subtle geographic changes in dialect.
Many bird songs have regional distinguishing differences in dialect.
Often, when two populations of the same species become separated, or isolated, they develop their own unique dialect. These recordings are also used as an aid to doing census counts. Perhaps 200 years from now someone will listen to this collection and learn a great deal about what happened in 1997. Karen is an ornithologist and assistant to the Texas Breeding Bird Atlas Project. The CDs contain the songs and calls of 29 bird species found in Texas.