Sphenisciformes

Genomic analyses detected some of the episodes of ancient introgression among erect-crested and the ancestral rockhopper penguin species, erect-crested and macaroni/royal penguins, and the Galápagos/Humboldt ancestor and Magellanic penguins (Vianna et al. 2020)

Several hybrid penguins have been reported in the wild.

Eudyptes

• Rockhopper Penguin (E. chrysocome) x Erect-crested Penguin (E. sclateri) – Naupier (1968)
• Rockhopper Penguin (E. chrysocome) x Royal Penguin (E. schlegeli) – Simpson (1985)
• Rockhopper Penguin (E. chrysocome) x Macaroni Penguin (E. chrysolophus) – Woehler & Gilbert (1990), White & Clausen (2002)

A genetic study reported gene flow between the Northern Rockhopper Penguin (E. moseleyi) and the Southern Rockhopper Penguin (E. chrysocome), and between two subspecies (chrysocome and filholi) of the Southern Rockhopper Penguin (Mays et al., 2019).

Spheniscus

• Humbolt Penguin (S. humboldti) x Magellanic Penguin (S. magellanicus) – Simeone et al. (2009), Hibbets et al. (2020)

Hybrid Macaroni (E. chrysolophus) X Rockhopper Penguin (E. chrysocome)

References

Hibbets, E. M., Schumacher, K. I., Scheppler, H. B., Boersma, P. D., & Bouzat, J. L. (2020). Genetic evidence of hybridization between Magellanic (Sphensicus magellanicus) and Humboldt (Spheniscus humboldti) penguins in the wild. Genetica, 148(5), 215-228.

Mays Jr, H. L. et al. (2019). Phylogeography, Population Structure, and Species Delimitation in Rockhopper Penguins (Eudyptes chrysocome and Eudyptes moseleyi). Journal of Heredity, 110(7), 801-817.

Napier, R. (1968). Erect-crested and Rockhopper Penguins interbreeding in the Falkland Islands. British Antarctic Survey Bulletin 16, 71-72.

Simeone, A., Hiriart–Bertrand, L., Reyes-Arriagada, R., Halpern, M., Dubach, J., Wallace, R., Putz, K. & Luthi, B. (2009). Heterospecific Pairing and Hybridization between Wild Humboldt and Magellanic Penguins in Southern Chile. Condor 111, 544-550.

Simpson, K. N. G. (1985). A Rockhopper x Royal Penguin hybrid from Macquarie Island. Australian Bird Watcher 11, 35-45.

Vianna, J. et al. (2020). Genome-wide analyses reveal drivers of penguin diversification. Proceedings of the National Academy of Sciences, 117(36), 22303-22310.

White, R. W. & Clausen, A. P. (2002). Rockhopper Eudyptes chrysocome chrysocome x Macaroni E. chrysolophus penguin hybrids apparently breeding in the Falkland Islands. Marine Ornithology 30, 40-42.

Woehler, E. J. & Gilbert, C. A. (1990). Hybrid rockhopper-macaroni penguins, interbreeding and mixed species pairs at Heard and Marion Islands. Emu 90, 198-201.