Singing behavior in polygynous Grey Thrush Turdus cardis males

抄録

The singing behavior of 17 Grey Thrush Turdus cardis males was studied in a coastal forest in Kanazawa in 1996–1997. Fourteen males made dawn trips from their primary singing areas to a secondary singing area. Three males made multiple daytime trips to these areas. The frequency of trips made by two of the males decreased as breeding progressed in the primary singing area. The third male became to make frequent daytime trips to a secondary singing area after mating with a new female in the secondary area. In the areas where the males had not mated previously, they sang with high Pfs (proportion of full songs in a song bout), whereas in the areas where mating had already occurred Pfs were low. Making frequent trips between singing areas and changing the frequency of full song in song bouts are thought to be parts of a strategy to achieve polygyny.