Seasonal patterns of singing in relation to breeding in the Nightingale, Luscinia megarhynchos
Kim G. Mortega • Constance Scharff • Henrike Hultsch
In birds, song plays an important role in sexual selection and territoriality. In this study, we examined the implications of social context on song during the breeding season. Specifically, we tested seasonal patterns of song in relation to mating status and to the breeding season of females in Nightingales, Luscinia megarhynchos. We predicted that if mate attraction is a key function of song, then mated males should change their singing behavior after pair formation. In contrast, if song is mainly used in territory defense, we expected no difference in song traits between mated and unmated males. Furthermore, we conducted playback experiments to investigate seasonal patterns of song during vocal interactions. Vocal interactions have been shown to be important during intra- as well as intersexual contexts.
Mated males decreased their overall song performance and often ceased to sing nocturnally after pair formation. In contrast, the song of unmated males did not change during the breeding season. Mated males responded stronger to playback than unmated males.
The results suggest that mating status is a key factor affecting song behavior specifically also during vocal interactions. Song traits like song overlapping and matching are used flexibly during vocal interactions. Individual differences in song and response behavior suggest further that the motivational state or the quality of a territorial male is important for decisions on how it responds vocally.
photo credit: Josef Vorholt