Spectral Characteristics of Common Iora Aegithina tiphia Vocalizations and their Context-Specific Preferences

Spectral properties such as duration of signal and frequency range were studied in Common Iora Aegithina tiphia vocalizations. Bird calls were sampled from different locations of the study area at different times to capture variability of their vocal signals in space and time. Along with call recordings, behaviour parameters such as presence of male or female conspecific members and their activities were recorded. From 48 bird call data, a total of 240 min of recordings was analysed. The most commonly uttered 15 syllables were identified, of which 14 were produced by males and the remaining one by females. Basic statistics of the spectral characteristics along with the observed behavioural parameters explain the natural history of Common Iora. The duration of syllable and frequency parameters such as low and high frequencies varied significantly across the 15 syllables. Common Iora males were recorded as using high frequency syllables with shorter duration as ‘contact calls’ with the nearby conspecific members, while low frequency ‘long distance’ calls were used by solitary males. Though these context preferences are not conclusive in nature based on this brief study, it suggests existence of context specificity of spectral characteristics in bird vocalizations.