Sound spectrograms have been a traditional method for comparing animal vocalizations and demonstrating their similarities or differences, but quantification of the comparative process has been difficult. This lack of quantification has hindered progress in documenting the timing and degree of song development in song birds. With this in mind, computer‐based methods for sound comparison and sound averaging were developed. These methods utilize a numerical representation of a sound's frequency‐time structure to compute a similarity value between any two sounds and an average sound spectrogram for a set of sounds. These analytical techniques were applied to an analysis of song notes of the swamp sparrow (Melospiza georgiana). The results demonstrate the usefulness of the methods and reveal new details in the description of the swamp sparrow's set of species‐universal note types and in the decrease of note variability during the course of developmental transitions from subsong, through plastic song to song crystallization.

No abstract

No abstract

No abstract

The Borror Laboratory of Bioacoustics (BLB) at The Ohio State University is a research facility with an archive of recorded animal sounds collected primarily by BLB staff and associates. The 25<th>000 sound recordings are scientific data that require special treatment to ensure their longevity, and the BLB is, like other sound archives, dedicated to the preservation of these recorded sounds. Traditionally, sound recordings have been archived on analog 1/4-in. magnetic tape. However, magnetic tape is degraded by time, usage, and excess temperature and humidity. Additionally, access to data on analog tapes is slow. Facing loss of access to data, especially on tapes exceeding their 50-year life expectancy, we are copying the collection to digital format [compact disk recordable (CDR)] with the aid of funding from the National Science Foundation. Because digital technology has been tested and refined over nearly two decades, and CDR media for storage of digital data now sustains a viable commercial market, archives can today endorse their use. We present the limitations of analog technology, the limitations and benefits of digital technology and CD storage, and outline the production process and safeguards developed by us for this task. [Work supported by NSF DEB-9613674.]