Hybridisation in kiwi (Apteryx; Apterygidae) requires taxonomic revision for great spotted kiwi

We review hybridisation in kiwi (Apteryx spp.) and present new genetic data examining the extent of hybridisation between rowi (A. rowi) and little spotted kiwi (A. owenii) at Okarito, the location of the only remaining natural population of the threatened rowi. We find evidence of recurrent hybridisation between these two species over the last 150 years, including one F1 hybrid found in the last 15 years, despite little spotted kiwi’s likely extinction on the mainland in the 1970s. However, we found little evidence of introgression of little spotted kiwi alleles into rowi, indicating that hybridisation is not an ongoing threat to rowi. The syntype specimens of A. haastii Potts, 1872 collected from near Okarito in the 1870s, are also hybrids and are not representative of the prevailing usage of the name for the great spotted kiwi. Therefore, we resurrect the nomen oblitum A. maxima Sclater & Hochstetter, 1861, for this large spotted kiwi species.