Seasonal and diurnal patterns of singing and song-flight activity in bluethroats (Luscinia svecica)

To assess the functions of male song in Bluethroat (Luscinia svecica svecica), seasonal and diurnal patterns of song and song-flight activity were analyzed by using data on individually marked birds. The seasonal patterns of singing and song-flight activity were found to peak shortly after male arrival and before the onset of egg laying. The diurnal pattern of song production peaked in the early morning (0300-0900), with a less clear increase in song rate around 2200. Male singing activity decreased significantly after clutch initiation. Only unpaired males, or males that failed in their breeding attempt, were heard singing after the egg-laying period. Seasonal and diurnal patterns of song-flight activity were strongly correlated with patterns of singing activity. In addition, male pairing speed was positively correlated with song-flight activity. These results suggest that both song and song flights in Bluethroats serve to attract females.

Juha Merila and Jorma Sorjonen, Auk: Vol. 111, No. 3, July-September, 1994