Dawn trips made by the male Grey Thrush Turdus cardis to search for second mates

Abstract

The proportion of full songs (Pfs) in the song bout of a male Grey Thrush Turdus cardis indicates its desire to attract females. At dawn, male Grey Thrushes make trips away from their usual singing areas. In this study, I assessed the distance of the song points from the nest in relation to the Pfs. Song points with a high Pfs (mainly at dawn) were farther from the nest than those with a low Pfs (during daytime). I conducted playback experiments to compare territorial behavior between dawn and daytime singing areas. Responses were strong in the daytime singing area, but weak in the dawn singing area. It appears that male Grey Thrushes make dawn trips to attract second mates.