Comparing Introductory Vocalisations in Estrildids

Abstract

Introductory notes (INs) are notes that occur at the onset of the vocalisation in several species, including songbirds. In Zebra finches, songs start with a variable number of IN repeats, followed by a fixed motif sequence of syllables that repeats across the song bout. To examine if INs also have a species specific pattern, in this study we aim to characterise INs across relatives of the Zebra finch, i.e. the Estrildidae family. We also looked at and quantified some general properties of the birdsong as it would allow us to compare and correlate properties of INs with properties of the song that follows. It was seen that all the Estrildid species had fairly stereotyped songs that consistently began with a few fixed syllables, despite the vast repertoire of unique syllables that the bird was capable of producing. While the majority of these species were seen to produce repeats of this starting syllable, a few of these species did not do so. Across the species, it was seen that the INs changed their acoustic properties as they repeated themselves, consistently getting longer and gaps between them getting shorter as they proceeded to song. Across all species, irrespective of syllable identity or IN properties, it was seen that the birds produced syllables faster and faster as they began their song. There was also a lot of similarity in song and IN properties among species of the same genus.