Song mimicry, song dialects, and behavioural context of songs in brood-parasitic Straw-tailed Whydahs, Vidua fischeri

Abstract

Straw-tailed Whydahs, Vidua fischeri, mimic the songs and calls of their host species, the Purple Grenadier, Granatina ianthinogaster, and they also have songs that do not mimic the hosts. Neighbouring male whydahs match song themes with each other, while males a few km distant have another set of song themes. Certain song themes were given associated with aggressive contexts and sexual displays (three themes in sustained chase of an intruding male, four other themes in display to a visiting female). Song matching among neighbouring male whydahs is similar to that in Village Indigobirds, V. chalybeata, and suggests that social organisation is similar in the whydahs and indigobirds. A few males have songs like those of distant males and those songs are apparent markers of dispersal. The distribution of song behaviour traits among species points to early phylogenetic origins of the elaborate song repertoires and the mimicry of songs of their host species in brood-parasitic Vidua finches.


(Ostrich: 2003 74(1&2): 87–96)