The Yellow-eyed Penguin (Megadyptes antipodes) or Hoiho is a penguin native to New Zealand. Previously thought closely related to the Little Penguin (Eudyptula minor), molecular research has shown it more closely related to penguins of the genus Eudyptes. Like most other penguins, it is mainly piscivorous.
The species breeds around the South Island of New Zealand, as well as Stewart, Auckland and Campbell Islands. Colonies on the Otago Peninsula are a popular tourist venue, where visitors may closely observe penguins from hides, trenches or tunnels.
The Yellow-eyed Penguin is the sole extant species in the genus Megadyptes. (A smaller, recently extinct species M. waitaha was discovered in 2008.) Previously thought closely related to the Little Penguin (Eudyptula minor), new molecular research has shown it more closely related to penguins of the genus Eudyptes. Mitochondrial and nuclear DNA evidence suggests it split from the ancestors of Eudyptes around 15 million years ago.
The Yellow-eyed Penguin was described by Jacques Bernard Hombron and Honoré Jacquinot in 1841. The Maori name is Hoiho.
An angry and molting yellow-eyed penguin at Oamaru, New Zealand
This is a fairly large penguin, averaging 75 cm (30 in) long and weighing about 6.3 kg (14 lbs). Weights vary through the year being greatest, 7 to 8 kg (15.5-18 lbs), just before moulting and least, 5 to 6 kg (11-13.2 lbs), after moulting. It has a pale yellow head and paler yellow iris with black feather shafts. The chin and throat are brownish-black. There is a band of bright yellow running from its eyes around the back of the head. The juvenile has a grayer head with no band and their eyes have a gray iris.
The Yellow-eyed Penguin may be long lived, with some individuals reaching 20 years of age. Males are generally longer lived than females, leading to a sex ratio of 2:1 around the age of 10-12 years.
Distribution and habitat
A Yellow-eyed Penguin in The Catlins, New Zealand.
This penguin usually nests in forest or scrub, among Native Flax (Phormium tenax) and lupin (Lupinus arboreus), on slopes or gullies, or the shore itself, facing the sea. These areas are generally sited in small bays or on headland areas of larger bays. It is found in New Zealand, on the south-east coast of South Island, Foveaux Strait and Stewart Island/Rakiura, and Auckland and Campbell Islands. It expanded its range from the subantarctic islands to the main islands of New Zealand after the extinction of the Waitaha Penguin several hundred years ago.
The current status of this penguin is endangered, with an estimated population of 4,000. It is considered one of the world's rarest penguin species. The main threats include habitat degradation and introduced predators. It may be the most ancient of all living penguins.
A Yellow-eyed Penguin in the Curio Bay, New Zealand.
In spring 2004, a previously undescribed disease killed off 60% of Yellow-eyed penguin chicks on the Otago peninsula and in North Otago. The disease has been linked to an infection of Corynebacterium, a genus of bacteria that also causes diphtheria in humans. It has recently been described as diphtheritic stomatitis. However, it seems as if this is just a secondary infection. The primary pathogen remains unknown. A similar problem has affected the Stewart Island population.
The Yellow-eyed Penguin generally forages 7-13 km (4-8 miles) offshore, and travelling on average around 17 km (11 miles) away from the nesting site. Birds leave the colony at dawn and return the same evening during chick rearing, although may spend 2-3 days at sea at other times. Average depth dived is 34 m (112 ft).
The Yellow-eyed Penguin pursues prey in 20-60 m (66-196 ft) deep dives. Around 90% of the Yellow-eyed Penguin's diet is made up of fish; with cephalopods such as the arrow squid (Nototodarus sloanii) making up the remainder. Fish species consumed include the blue cod (Parapercis colias), red cod (Pseudophycis bachus), opalfish (Hemerocoetes monopterygius), and New Zealand blueback sprat (Sprattus antipodum), all between 2 and 32 cm (1-13 in) long. Cephalopods make up almost half (49%) of the diet of immature birds.
Yellow-eyed Penguins on the shore of Enderby Island, Auckland Islands.
Whether or not yellow-eyed penguins are colonial nesters has been an ongoing issue with penguin people in New Zealand. Most Antarctic penguin species nest in large high density aggregations of birds. For an example see the photo of nesting Emperor penguin. In contrast yellow-eyed penguins do not nest within visual sight of each other. While they can be seen coming ashore in groups of 4-6 or more individuals then disperse along track to individual nests sites out of sight of each other. The consensus view of New Zealand penguin workers is that it is preferable to use habitat rather than colony to refer to areas where yellow-eyed penguins nest.
Yellow Eyed Penguin emerging from sea.
Penguins and humans
Several mainland habitats have hides and are relatively easily accessible for those wishing to watch the birds come ashore. These include beaches at Oamaru, Moeraki light-house, a number of beaches near Dunedin, and The Catlins. In addition commercial tourist operations on Otago Peninsula also provide hides to view yellow-eyed penguins.
A reserve protecting more than 10% of the mainland population was established at Long Point in the Catlins in November 2007 by the Department of Conservation and the Yellow-eyed Penguin Trust.
- The Hoiho appears on the reverse of the New Zealand $5 note.
- The Yellow-eyed Penguin is used as mascot for the recycling campaign of the City of Dunedin.
- The Yellow-eyed Penguin is also featured in Farce of the Penguins, in which they complain about global warming. Ironically, the natural habitat of these birds is nearly always lacking snow.