Social Context–Dependent Vocal Strategies in the Territorial Songs of Oriental Magpie Robin Copsychus saularis

Abstract

Territorial songs are fundamental to avian communication, allowing males to secure and defend resource-rich spaces through conspicuous vocal displays during the breeding season. These signals function both as long-range advertisements in the absence of rivals and as aggressive displays when rivals challenge territorial boundaries. This study examines territorial songs in Oriental Magpie Robin (OMR) Copsychus saularis in two different social contexts. Songs from a total of 29 male individuals were recorded along with the field observations about the absence/presence of male intruders. Songs produced in the absence of male intruders were classified as solo songs and in the presence as rival-present songs. Spectral, temporal and structural features of the songs were derived from the spectrograms and a comparative analysis of the songs in the two social contexts was performed. We found that territorial songs in OMR differed significantly with social context, with rival-present singing showing higher song rate driven by reduced inter-phrase gaps. These findings identify temporal modulation as the primary mechanism of territorial escalation in OMR, suggesting that elevated song rate reflects aggressive motivation towards intruding males.