ResearchPublished 2 May 2019
The spread of Waitaha penguins
Researchers have found that the now extinct Waitaha penguin may have lived further north in Aotearoa New Zealand than originally thought.
Published in the New Zealand Journal of Zoology, the article ‘Evidence for breeding of Megadyptes penguins in the North Island at the time of human arrival’ by researchers Nic Rawlence, Alan Tennyson, Theresa Cole, Alexander Verry & Paul Scofield looks into new archaeological and palaeontological evidence for which areas were inhabited by the now-extinct Waitaha penguin (Megadyptes antipodes waitaha).
Human arrival in Aotearoa New Zealand around 750 years ago led to the extinction of many species, including the Waitaha penguin. Though this species was thought to breed exclusively on the coast of the South Island and Stewart Island, recent genetic testing of penguin bones from further north shows that these birds may have been a common resident of the lower North Island.
The use of ancient DNA analysis has provided evidence to suggest the Waitaha penguin resided in a wider range of areas than previously thought. Several bones of large penguins that had been found in the North Island have been confirmed as belonging to Waitaha penguins. Previously, it was too difficult to make this conclusion as the bones of the Waitaha penguin are very similar to crested penguins (Eudyptes spp.), and therefore could not be distinguished.
If only a small number of Waitaha penguin bones had been found, it would suggest that these penguins had travelled up from the South Island. However, due to the relatively large number of Waitaha penguin bones found (at five different sites: Manurewa Point, Tekaukau Point, Paekakariki, Mana Island and Paremata), it was concluded that this penguin was not a rare visitor in the north, but rather a permanent resident in the lower North Island. These North Island Waitaha penguins were part of a northern genetic lineage, suggesting colonisation of the north did not originate from more southerly breeding colonies. Fossil bones are the only evidence for mapping the prehistoric range of the Waitaha penguin, as there is no direct evidence of their breeding sites anywhere in the country. Evidence of previous nesting sites, such as eggs or juvenile remains, of any seabird species, is rare in Aotearoa New Zealand.
The likely cause of the extinction of the Waitaha penguin, similar to most large bird extinctions in Aotearoa New Zealand, was human hunting. Extinction time modelling has shown that the Waitaha penguin was extinct in the South Island by the late 15th century. In the North Island, they may have gone extinct at the same time or earlier due to a higher level of human pressure in the north.
The article ‘Evidence for breeding of Megadyptes penguins in the North Island at the time of human arrival’ published in the New Zealand Journal of Zoology is available to read in full at Taylor & Francis Online. The wider implications of this study can be read on Dr Nicolas Rawlence’s ‘Lost Worlds, Vanished Lives ’ Sciblog.