Kiwis are flightless birds native to New Zealand, in the genus Apteryx and family Apterygidae. Hybridization between several species has been suggested.
Species Accounts
- Apteryx australis (Southern Brown Kiwi)
- Apteryx haastii (Great Spotted Kiwi)
- Apteryx mantelli (North Island Brown Kiwi)
- Apteryx owenii (Little Spotted Kiwi)
- Apteryx rowi (Okarito Kiwi)
Scientific Literature
The population of kiwis on Kapiti Island might be of hybrid origin: Northern Brown Kiwi (A. mantelli) x Southern Brown Kiwi (A. australis). A bird from the Franz Josef township was a hybrid between Little Spotted Kiwi (A. owenii) and Southern Brown Kiwi (Herbert & Daugherty, 2002). A phylogeographic study using ancient DNA suggested that the decline of Little Spotted Kiwi might have increased the probability of hybridization with other species (Shepherd et al., 2012).
A genetic study found evidence of recurrent hybridization between Okarito Kiwi (A. rowi) and Little Spotted Kiwi (A. owenii) over the last 150 years, including one F1 hybrid found in the last 15 years (Shepherd et al. 2021). Moreover, the syntype of the Great Spotted Kiwi (A. haastii) turned out to be a hybrid between these two species.

References
Herbert, J., & Daugherty, C. H. (2002). Genetic variation, systematics and management of kiwi (Apteryx spp.). In: Some early 1990s studies in kiwi (ed. Overmars, F.), pp.10-33.
Shepherd, L. D., Worthy, T. H., Tennyson, A. J., Scofield, R. P., Ramstad, K. M., & Lambert, D. M. (2012). Ancient DNA analyses reveal contrasting phylogeographic patterns amongst kiwi (Apteryx spp.) and a recently extinct lineage of spotted kiwi. PLoS One, 7(8):e42384.
Shepherd, L. D., Tennyson, A. J., Robertson, H. A., Colbourne, R. M., & Ramstad, K. M. (2021). Hybridisation in kiwi (Apteryx; Apterygidae) requires taxonomic revision for the Great Spotted Kiwi. Avian Research, 12(1), 1-13.