Many male passerines show a marked peak of singing activity before sunrise. It is generally believed that the main functions of the dawn song are mate attraction and territory defence. We examined whether seasonal patterns of dawn song characteristics (i.e. song rate and level of song complexity) of male Pied Bush Chat were related with different breeding stages (unpaired, laying, nestling and fledgling). It was predicted that if the main function of dawn singing in Pied Bush Chat is to attract the female, then males should change their dawn singing behaviour after pairing. In contrast, if dawn singing is mainly used in territory defence, we expected no difference in song characteristics in males throughout the breeding season. Song samples were collected from 9 singing males during February to August 2008 in and around Haridwar town (29°55`N and 78° 08`E; Himalaya foothills of Uttarakhand State) using Marantz PMD 670 sound recorder and Sennheiser ME 67 unidirectional microphone. Song spectrograms were prepared with Avisoft SAS LabPro software (version 4.2). Analysis of the song samples of 9 males revealed that both the measures of dawn song performance remained largely constant throughout the breeding season as no significant differences were found in song rate (F= 1.16, df= 3, 32, P> 0.001) and song complexity (F= 0.46, df= 3, 32, P> 0.001) among different breeding stages. These findings suggest that in Pied Bush Chat song at dawn is important in defending the territory throughout the breeding season.
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