Silke Kipper, Juniorprofessorin
In many song bird species females choose mates based on song characteristics such as song output, complexity, vocal performance or repertoire size. Therefore, male song characteristics are thought to be the result of inter- (and intra-) sexual selection. Male nightingales Luscinia megarhynchos possess extremely large song type repertoires (mean/SD 186 +/- 26) (1). The use of large repertoires in territorial interactions among males, allowing song type matching and thereby addressing neighbours or other conspecifics, was examined in several studies (2). By contrast, little is known about song preferences of female nightingales. Do females base their mate choice decisions on the versatility of a repertoire, or do they pay more attention to the quality of acoustic features within songs as was shown for females of song bird species with smaller repertoires (e.g. 3). We are going to investigate such preferences by applying operant conditioning techniques where the control over song playback is left with the subject (4). This will allow us to assess preferences for song or certain song features either consecutively or even simultaneously by providing a choice between two stimuli. Investigating the behaviour of hand-reared females who, as fledglings, will be exposed to a set of species-specific songs under controlled lab conditions, will in addition allow us to address the role of early experience with songs in the formation of preferences in adult birds.
(1) Kipper, S.; Mundry, R.; Hultsch, H.; Todt, D. 2004: Long-term persistence of song performance rules in nightingales (Luscinia megarhynchos): A longitudinal field study on repertoire size and composition. Behaviour 141: 371-390.
(2) Todt, D. & Naguib, M. 2000: Vocal interactions in birds: The use of song as a model in communication. Advances in the Study of Behaviour 29: 247-296.
(3) Ballentine, B.; Hyman, J.; Nowicki, S. 2004: Vocal performance influences female response to male bird song: an experimental test. Behavioral Ecology 15: 163-168.
(4) Riebel, K. & Slater, P. J. B. 1998: Testing female chaffinch song preferences by operant conditioning. Animal Behaviour 56: 1443-1453.