Kororā, or little penguin (Eudyptula minor), is the only penguin species currently breeding at the Chatham Islands, however that has not always been the case. Two extinct penguins that were endemic to the Chatham Islands have recently been described and, while not breeding, several other species of penguin also occasionally visit the islands.
The Chatham kororā are the same species found around most of New Zealand, with exception being Otago having the Australian little penguin. Little penguins vary slightly in appearance around the country, for example in the north of the North Island they have a brown tint to the face. Chatham kororā can be distinguished by their bills being more robust than most of their mainland kin.
The size of the kororā population on the Chathams is unknown, but certainly in the thousands. They are abundant on the north coast of Chatham Island where they nest in dense marram grass of the dunes, and on predator-free Rangatira and Mangere Islands.
Little is also known of the breeding or foraging ecology of Chatham Island kororā, the only study of the latter capturing two foraging trips from a single individual from Rangatira Island. Like their mainland cousins, they are likely to dive to depths of up to 35m in search of small fish.
The islands closest to the Chathams, the Bounty and Antipodes Islands, is the home of the most common visitors – erect-crested and rockhopper penguins. Most penguin visitors do so to moult, the annual replacement of all feathers that requires them to be ashore for around 3 weeks. Other penguin visitors have included Snares, rockhopper, royal, king, and a male yellow-eyed penguin who was resident on Rangatira from 1984-93.
The bones of an extinct crested penguin were long-known from the Chatham Islands, but was only recently that the species was described. When it was, by examining sub-fossil bones and DNA, a second penguin species was unexpectedly revealed. The crested penguin is closely related to the erect-crested penguin of the nearby (in penguin terms) Bounty and Antipodes Islands, and is named Eudyptes warhami, honouring John Warham (1919–2010), who carried out pioneering studies on Eudyptes penguins.
The second penguin was a subspecies of the yellow-eyed penguin, the smallest of the three now known. Named Megadyptes antipodes richdalei, the subspecies name honours Lance Richdale (1900–1983), who carried out pioneering studies on yellow-eyed penguins.
The presence of both species in middens on the islands, and an absence of reliable historical sightings suggests that these penguins were driven to extinction shortly after human settlement.
Cole, T. L. et al. (2019). Ancient DNA of crested penguins: Testing for temporal genetic shifts in the world’s most diverse penguin clade, Molecular phylogenetics and evolution, 131, pp. 72–79. doi: 10.1016/j.ympev.2018.10.025.
Grosser, S. et al. (2016) ‘Invader or resident? Ancient-DNA reveals rapid species turnover in New Zealand little penguins’, Proceedings of the Royal Society B: Biological Sciences, 283(1824), p. 20152879. doi: 10.1098/rspb.2015.2879.
Miskelly, C. M. and Bester, A. J. (2006) ‘Additions to the Chatham Islands’ bird list, with further records of vagrant and colonising bird species’, Notornis, 53, pp. 215–230. Available at: http://notornis.osnz.org.nz/system/files/Notornis_53_2_215.pdf.