The Australasian Robins are all endemic to New Guinea, Australia, New Zealand and numerous Pacific Islands. Only one genus displays hybridization, Petroica. A phylogenetic study of this genus found that the Black Robin (P. traversi) is not a derivative of the New Zealand Robin (P. australis), instead it groups strongly with the Tomtit (P. macrocephala). This finding could indicate hybridization, or incomplete lineage sorting (Miller & Lambert, 2006). Indeed, hybridization between these species has been documented using minisatellites (Ma & Lambert, 1997). However, hybrids have been removed from the population and a recent genetic study found no evidence for introgression (Cubrinovska, Massaro & Hale, 2016).
Two isolated and inbred populations of the New Zealand Robin were rescued genetically by introducing outbred individuals. This ‘genetic rescue’ technique shows that hybridization can be used as a conservation tool (Heber et al., 2013).
Cubrinovska, I., Massaro, M. & Hale, M. L. (2016). Assessment of hybridisation between the endangered Chatham Island black robin (Petroica traversi) and the Chatham Island tomtit (Petroica macrocephala chathamensis). Conservation Genetics 17, 259-265.
Heber, S., Varsani, A., Kuhn, S., Girg, A., Kempenaers, B. & Briskie, J. (2013). The genetic rescue of two bottlenecked South Island robin populations using translocations of inbred donors. Proceedings of the Royal Society B-Biological Sciences 280.
Ma, W. & Lambert, D. (1997). Minisatellite DNA markers reveal hybridisation between the endangered black robin and tomtit. Electrophoresis 18, 1682-1687.
Miller, H. C. & Lambert, D. M. (2006). A molecular phylogeny of New Zealand’s Petroica (Aves : Petroicidae) species based on mitochondrial DNA sequences. Molecular Phylogenetics and Evolution 40, 844-855.