Acquisition of Serial Signal patterns in Birds: Temporal Cues are Mediators for Song Organization [abstract]

Henrike Hultsch and Dietmar Todt (1992). Acquisition of Serial Signal patterns in Birds: Temporal Cues are Mediators for Song Organization [abstract]. Bioacoustics, Volume 4 (1): 61 -62

The singing behaviour of birds is an established model for studies on the mechanisms that mediate between environmental stimulation and behavioural performance. This has been documented e.g. for the memory mechanisms which underlie the acquisition of both single song patterns and serial information encoded in longer trains of songs (Hultsch and Todt, 1989a: J. Comp. Physiol., 165, 197-203). To examine this matter further, handraised nightingales Luscinia megarhynchos, aged 3-9 weeks, were exposed to strings of master song types, such as (A1, A,2, . . .A12), (B1, B2, . . .B12), (C1, C2, . . . C12), etc. One experimental variable was the stimulus-free time interval between playbacks of different strings (interval durations: 0.5min, 2min, 5min, 30min, 1h, 6h, 12h). The analysis of singing behaviour in the adult subjects (age: 11 months) revealed the following results: Imitations developed from master song types of the same string were performed together (i.e. sequentially associated) and at the same time sequentially segregated from imitations of master songs that had been components of other strings. However, this effect was found only with inter-string intervals beyond a 'critical' duration: whereas the effect was highly significant if intervals had lasted 5min or longer, it was less marked with inter-string intervals of 2min. If intervals between two different strings had been only 0.5min, these strings were processed as just one string: song-type imitations from these strings did not form different 'context groups' ('context effect'; Hultsch and Todt 1989b: Naturwissenschaften, 76, 584-586). Nevertheless, the boundary between such strings caused a boundary between song-type packages. (For details on the phenomenon of song-type packages see: Hultsch and Todt 1989a, as given above.)