Hybrid male Vidua were observed in the field and recorded to document host song mimicry. The mtDNA of one male was sequenced to identify the maternal parent. The hybrid males mimicked songs of Melba Finch (Pytilia melba), the usual host of Long-tailed Paradise Whydah (V. paradisaea), but the mtDNA matched that of indigobirds (V. chalybeata or another species), which parasitize and mimic other estrildid finches. This combination of song behavior and genetics is consistent with a two-generation history that began with a female indigobird (e.g. V. chalybeata) laying in a Melba Finch nest rather than in a nest of her usual host (e.g. Red-billed Firefinch [Lagonosticta senegala]). Her daughter, genetically an indigobird, imprinted on her Melba Finch foster parents and then mated with a male paradise whydah mimicking Melba Finch song. She also laid eggs in Melba Finch nests. Her son, the male hybrid carrying his grandmother's indigobird mtDNA, learned and later mimicked Melba Finch song. Genetic identification of the maternal species origin of this hybrid supports a model of mate choice based on mimetic song in the Vidua finches.