Yellow-eyed penguin
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The yellow-eyed penguin (Megadyptes antipodes), known also as hoiho, is a species of penguin endemic to New Zealand.<ref name=":1">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name=":4">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It is the sole extant species in the genus Megadyptes.
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 penguins, it is mainly piscivorous.
The species breeds along the eastern and south-eastern coastlines of the South Island of New Zealand, as well as Stewart Island, Auckland Islands, and Campbell Islands. Colonies on the Otago Peninsula are a popular tourist venue, where visitors may closely observe penguins from hides, trenches, or tunnels.
On the New Zealand mainland, the species has experienced a significant decline over the past 20 years. On the Otago Peninsula, numbers have dropped by 75% since the mid-1990s and population trends indicate the possibility of local extinction in the next 20 to 40 years. While the effect of rising ocean temperatures is still being studied, an infectious outbreak in the mid-2000s played a large role in the drop. Human activities at sea (fisheries, pollution) may have an equal if not greater influence on the species' downward trend.<ref>Template:Cite journal</ref>
TaxonomyEdit
The yellow-eyed penguin was first described by Jacques Bernard Hombron and Honoré Jacquinot in 1841.
The yellow-eyed penguin is the sole species in the genus Megadyptes. It was previously thought closely related to the little penguin but new molecular research has shown it is 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. In 2019 the 1.25Gb genome of the species was published as part of the Penguin Genome Consortium,<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> and this will help resolve the origins and aid conservation by helping to inform any future breeding programmes.
SubspeciesEdit
- M. a. antipodes, yellow-eyed penguin. The only extant subspecies. Formerly most abundant in the subantarctic Auckland and Campbell Islands, it colonised Stewart Island / Rakiura and part of the South Island after the extinction of the Waitaha penguin.<ref name="Rawlence-penguin">Rawlence, Nicolas J., et al. "Radiocarbon-dating and ancient DNA reveal rapid replacement of extinct prehistoric penguins Template:Webarchive". Quaternary Science Reviews 112 (2015): 59–65.</ref>
- M. a. waitaha, Waitaha penguin. Extinct.<ref name ="NZTCS">{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref> Was present in the North Island,<ref name="Rawlence-penguin"/> South Island,<ref name=nzbirdsonline_waitaha>Template:Cite book</ref><ref name=":1"/> Stewart Island,<ref name=":11">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and Codfish Island / Whenua Hou.<ref name=nzbirdsonline_waitaha /> Last dated to 1347–1529 AD.<ref name="Rawlence-penguin"/> It was discovered by University of Otago and University of Adelaide<ref name="reuters1120">Template:Cite news</ref> scientists comparing the foot bones of 500-year-old, 100-year-old and modern specimens of penguins. According to lead researcher Sanne Boessenkool, Waitaha penguins "were around 10% smaller than the yellow-eyed penguin. The two species are very closely related, but we can't say if they had a yellow crown."<ref name="BBC1120">Template:Cite news</ref> The penguin was named for the Māori iwi (tribe) Waitaha, whose tribal lands included the areas the Waitaha penguin are thought to have inhabited.<ref name="boessenkool" /> "Our findings demonstrate that yellow-eyed penguins on mainland New Zealand are not a declining remnant of a previous abundant population, but came from the subantarctic relatively recently and replaced the extinct Waitaha penguin," said team member Dr Jeremy Austin, deputy director of the Australasian Centre for Ancient DNA.<ref>Template:Cite press release</ref> Archaeological remains indicate that early Polynesian settlers hunted the species and that this, with possible additional predation by Polynesian rats and dogs, was a probable cause of extinction.<ref name=":11"/> As the local Māori people have no record of this subspecies,<ref name=BBC1120 /> it is estimated to have perished between c. 1300 and 1500, soon after Polynesian settlers arrived in New Zealand.<ref name=ODT1120>Template:Cite news</ref> Described as a new species M. waitaha in 2009,<ref name="boessenkool">Template:Cite journal</ref> but reclassified as a subspecies M. a. waitaha in studies from 2019<ref name=":7">Template:Cite journal</ref> and 2022.<ref>Template:Cite journal</ref> After their extinction, their range was occupied by yellow-eyed penguins (now Megadyptes antipodes antipodes), previously most abundant in the subantarctic islands further south. The decrease in sea lion populations after human settlement may also have eased their expansion. Another coauthor, Dr Phil Seddon, said "these unexpected results highlight ... the dynamic nature of ecosystem change, where the loss of one species may open up opportunities for the expansion of another."<ref>Template:Cite press release</ref>
- M. a. richdalei, Richdale's penguin.<ref name=":1"/> Extinct. A dwarf subspecies from the Chatham Islands. Last dated after the 13th century. It was hunted to extinction.<ref name=":7" />
DescriptionEdit
The yellow-eyed penguin (M. a. antipodes) is most easily identified by the band of pale yellow feathers surrounding its eyes and encircling the back of its head.<ref name=Heather2015p40>Template:Cite book</ref> Its forehead, crown and the sides of its face are slate grey flecked with golden yellow.<ref name=":2">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Its eye is yellow.<ref name=":1" /><ref name=Heather2015p40 /> The foreneck and sides of the head are light brown.<ref name=":1" /> The back and tail are slate blue-black.<ref name=":1" /><ref name=":2" /> Its chest, stomach, thighs and the underside of its flippers are white in colour.<ref name=":1" /> Juvenile birds have a greyer head with no yellow band around their eyes.<ref name=Heather2015p40 />
It is the largest living penguin to breed on the mainland of New Zealand and the fourth or fifth heaviest living penguin by body mass.<ref name=":1" /><ref name= CRC>Template:Cite book</ref> It stands Template:Convert tall and weighs Template:Convert.<ref name=":1" /><ref name=Marion>Marion, Remi (1999). Penguins: A Worldwide Guide. Sterling Publishing Co. Template:ISBN</ref> Weight varies throughout the year, with penguins being heaviest just before moulting, during which they may lose 3–4 kilograms in weight.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Males at around Template:Convert on average are somewhat heavier than females at an average of Template:Convert.<ref name= CRC/><ref name=Marion /><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
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.<ref>Template:Cite book</ref>
The yellow-eyed penguin is mostly silent.<ref name=":1" /> It makes a shrill bray-like call at nest and breeding sites.<ref name=":4" />
Distribution and habitatEdit
Until recently, it was assumed that M. a. antipodes was widespread and abundant before the arrival of Polynesian settlers in New Zealand. However, genetic analysis has since revealed that its range only expanded to include mainland New Zealand in the past 200 years. Yellow-eyed penguins expanded out of the subantarctic to replace New Zealand's endemic Waitaha penguin (M. waitaha). The Waitaha penguin became extinct between about 1300 and 1500, soon after Polynesian settlers arrived in New Zealand.<ref name="boessenkool" /><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Jeremy Austin, a member of the team that discovered the Waitaha penguin, said, "Our findings demonstrate that yellow-eyed penguins on mainland New Zealand are not a declining remnant of a previous abundant population, but came from the subantarctic relatively recently and replaced the extinct Waitaha penguin."<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
A dwarf subspecies from the Chatham Islands, M. a. richdalei, is extinct.<ref name=":7" /> The modern population of yellow-eyed penguins does not breed on the Chatham Islands.
Today, yellow-eyed penguins are found in two distinct populations.<ref name=":5">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The northern population extends along the southeast coast of the South Island of New Zealand, down to Stewart Island / Rakiura and Codfish Island / Whenua Hou.<ref name=":1" /> It includes four main breeding areas in Banks Peninsula, North Otago, Otago Peninsula and the Catlins. It is also referred to as the mainland population.<ref name=":4" /> The southern population includes the subantarctic Auckland Islands and Campbell Island / Motu Ihupuku.<ref name=":5" /> There is little gene flow between the northern and southern populations as the large stretch of ocean between the South Island and subantarctic region and the subtropical convergence act as a natural barrier.<ref>Template:Cite journal</ref> Based on monitoring between 2012-2017, there are on average 577 breeding pairs per year on Enderby Island in the Auckland Islands, which comprise 37-49% of the total breeding population for the species.<ref>Template:Cite journal</ref>
BehaviourEdit
BreedingEdit
Whether yellow-eyed penguins are colonial nesters has been an ongoing point of debate among zoologists in New Zealand. Most Antarctic penguin species nest in large, high density aggregations of birds; in contrast, yellow-eyed penguins do not nest within sight of each other. While they can be seen coming ashore in groups of four to six or more individuals, they then disperse along tracks to individual nest sites up to one kilometre inland.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>Template:Cite journal</ref> Accordingly, the consensus among New Zealand penguin workers is to use habitat rather than colony to refer to areas where yellow-eyed penguins nest.
The species prefers to nest in secluded, dense coastal forests, away from human settlements.<ref>Template:Cite journal</ref> First breeding occurs at three to four years of age and long-term partnerships are formed. Nest sites are selected in August and normally two eggs are laid in September. The incubation duties (lasting 39–51 days) are shared by both parents, who may spend several days on the nest at a time. For the first six weeks after hatching, the chicks are guarded during the day by one parent while the other is at sea feeding. The foraging adult returns at least daily to feed the chicks and relieve the partner. After the chicks are six weeks of age, both parents go to sea to supply food to their rapidly growing offspring. Chicks usually fledge in mid-February and are totally independent from then on. Chick fledge weights are generally between 5 and 6 kg.
FeedingEdit
Around 90% of the yellow-eyed penguin's diet is made up of fish, chiefly demersal species that live near the seafloor, including silversides (Argentina elongata), blue cod (Parapercis colias), red cod (Pseudophycis bachus), and opalfish (Hemerocoetes monopterygius).<ref>Moore, P.J.; Wakelin, M.D. 1997: Diet of the yellow-eyed penguin Megadyptes antipodes, South Island, New Zealand, 1991–1993. Marine Ornithology 25:17–29</ref><ref name="megadyptes">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Other species taken are New Zealand blueback sprat (Sprattus antipodum) and cephalopods such as arrow squid (Nototodarus sloanii). They also eat some crustaceans, including krill (Nyctiphanes australis). Recently, jellyfish were found to be targeted by the penguins. While initially thought that the birds would prey on jellyfish itself,<ref>Template:Cite journal</ref> deployments of camera loggers revealed that the penguins were going after juvenile fish and fish larvae associated with jellyfish.<ref>Template:Cite conference</ref>
Breeding penguins usually undertake two kinds of foraging trips: day trips where the birds leave at dawn and return in the evening ranging up to 25 km from their colonies, and shorter evening trips during which the birds are seldom away from their nest longer than four hours or range farther than 7 km.<ref name="Mattern2007">Mattern, T.; Ellenberg, U.; Houston, D.M.; Davis, L.S. 2007: Consistent foraging routes and benthic foraging behaviour in yellow-eyed penguins. Marine Ecology Progress Series 343: 295–306</ref> Yellow-eyed penguins are known to be an almost exclusive benthic forager that searches for prey along the seafloor. Accordingly, up to 90% of their dives are benthic dives.<ref name=Mattern2007 /> This also means that their average dive depths are determined by the water depths within their home ranges,<ref>Mattern, T.; Ellenberg, U.; Houston, D.M.; Lamare, M.; van Heezik, Y.; Seddon, P.J., Davis, L.S. 2013: The Pros and Cons of being a benthic forager: How anthropogenic alterations of the seafloor affect Yellow-eyed penguis. Keynote presentation. 8th International Penguin Conference, Bristol, UK. 2–6 September 2013</ref> but can swim up to 240 meters below the water surface.<ref>Template:Cite book</ref>
ConservationEdit
The yellow-eyed penguin is considered one of the rarest penguin species in the world.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It is listed on the IUCN Red List as being endangered. It was first included on the list in 1988 when it was listed as threatened. Its status has since been changed to endangered in the year 2000.<ref name=":6">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It is estimated that in the past 15 years the population has dropped by 75%.<ref>Template:Cite news</ref>
It had an estimated population of 4000 in 2007. The main threats include habitat degradation and introduced predators. It may be the most ancient of all living penguins.<ref>Other Penguin Species Template:Webarchive. Yellow-eyed Penguin Trust. Accessed 28 November 2007.</ref>
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.<ref>Gwyneth Hyndman, Land set aside for yellow-eyed penguin protection in Catlins Template:Webarchive. The Southland Times, Wednesday, 28 November 2007.</ref><ref>12km coastal reserve declared for yellow-eyed penguins Template:Webarchive, Radio New Zealand News, 27 November 2007.</ref>
In August 2010, the yellow-eyed penguin was granted protection under the U.S. Endangered Species Act.<ref name=Penguin>Five Penguins Win U.S. Endangered Species Act Protection Template:Webarchive Turtle Island Restoration Network</ref>
ThreatsEdit
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 been described as diphtheritic stomatitis and the pathogen identified.<ref>Template:Cite journal</ref> A similar problem has affected the Stewart Island population.<ref>Kerrie Waterworth, Mystery illness strikes penguins Template:Webarchive, Sunday Star Times, 25 November 2007.</ref> Treatment of chicks in hospital has proven successful with 88% of 41 chicks treated in 2022 surviving.<ref>Template:Cite journal</ref>
TourismEdit
Several mainland habitats have hides and are relatively accessible for those wishing to watch the birds come ashore. These include beaches at Oamaru, the Moeraki lighthouse, 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. However, the yellow-eyed penguin cannot be found in zoos because it will not reproduce in captivity.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Studies have shown however, that human presence in their habitats negatively impacts their foraging and breeding habits.<ref>Template:Cite journal</ref>
In cultureEdit
- The hoiho appears on the reverse side of the New Zealand five-dollar note.<ref>{{#invoke:citation/CS1|citation
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- The yellow-eyed penguin is the mascot to Dunedin City Council's recycling and solid waste management campaign.<ref>{{#invoke:citation/CS1|citation
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- The yellow-eyed penguin is also featured in Farce of the Penguins, in which they complain about global warming.
- In 2019 the yellow-eyed penguin was crowned the Bird of the Year in New Zealand, the first win for a seabird in the competition's 14-year history.<ref>Template:Cite news</ref> It was again victorious in the 2024 competition.<ref>Template:Cite news</ref>
See alsoEdit
ReferencesEdit
External linksEdit
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- BBC Science and nature page about Megadyptes waitaha
- Official Yellow-eyed Penguin Trust site in New Zealand
- Yellow-eyed penguin on PenguinWorld
- Yellow-eyed penguins from the International Penguin Conservation website
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