Predation is important to all animals and crucial to those animals that are threatened or endangered. Megadyptes antipodes falls under the crucial category because they are a threatened species. The key predators that threaten M. antipodes are terrestrial mammals that were introduced by humans. These predators include ferrets Mustela furo, feral house cats Felis catus, humans, and domestic dogs Canis lupus familiaris. Mustela furo and F. catus are responsible for predation of newly born penguins, while humans and C. lupus familiaris are the only terrestrial mammals that are capable of predation on adult yellow-eyed penguins. However, non-terrestrial predators include New Zealand sea lions Phocarctos hookeri. Yellow-eyed penguins do not have any anti-predator mechanisms against terrestrial mammals because they are a relatively new predator, although their conservation status does help serve as an anti-predator mechanism.
Known Predators:
Yellow-eyed penguins are relatively large in comparison to other penguins living in similar conditions. Their height ranges from 56 to 78 cm, with an average height of 70 cm. The mass of these penguins ranges from 5 to 8 kg. These physical characteristics make Megadyptes antipodes the largest penguin that does not live in the Antarctic. A defining trait of this particular penguin is their yellow eyes. The characteristic used to distinguish between adult and juvenile penguins is the presence of yellow plumage on the adult's heads. Yellow feathers are not present on juvenile penguins until they molt, around the age of one. Megadyptes antipodes exhibits sexual dimorphism: males have a carotenoid derived ornament. The difference in males and females can be seen in the pigmentation of the head feathers (plumage). Carotenoids are responsible for the bright yellow coloration of the male's head and are hypothesized to be a signal of parental quality, although few studies have been conducted on the subject.
Range mass: 5 to 8 kg.
Range length: 56 to 78 cm.
Average length: 70 cm.
Sexual Dimorphism: sexes colored or patterned differently; male more colorful
Other Physical Features: endothermic ; bilateral symmetry
The average lifespan of Megadyptes antipodes is 23 years. Male yellow-eyed penguins typically live longer than females. Predation does not play a big role in determining their lifespan. The factor with the most influence is the amount of breeding, those who do not or cannot breed typically live longer than those that do breed.
Average lifespan
Status: wild: 23 years.
Average lifespan
Status: wild: 23 years.
Yellow-eyed penguins inhabit island shorelines in New Zealand. Most of the shore is covered in coastal forest, where the penguins live and nest. These birds are primarily terrestrial and only enter the water to hunt.
Average elevation: 0 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: forest
Aquatic Biomes: coastal
Yellow-eyed penguins (Megadyptes antipodes) are island endemic and are found in the southern regions of New Zealand, including Stewart Island, South Island, the Otago Peninsula and a few other islands in the same region. These penguins are not migratory and stay in this range year round. They only leave the island to hunt off the coast of New Zealand and the respective islands they inhabit.
Biogeographic Regions: australian (Native )
Other Geographic Terms: island endemic
Potential mates communicate acoustically, via shrill calls. Their nest sites are usually well hidden, this call is used for mates to find each other, as well as juveniles. They do not receive much social stimuli from other penguins due to their isolated nature and are easily startled by humans.
Communication Channels: acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Megadyptes antipodes is endangered according to the IUCN Red List and is threatened according to the United States Federal list. The main cause contributing to the status of yellow-eyed penguins is deforestation on the coast of New Zealand. There are various conservation efforts, including penguin reserves, such as Penguin Place in Dunedin, New Zealand. These reserves allow visitors to view the penguins for a fee, which helps conserve M. antipodes. Another conservation effort is the Yellow-eyed Penguin Trust, which teaches people about the penguins and collects funds for their conservation. There are only a few thousand yellow-eyed penguins living in the world today.
US Federal List: threatened
CITES: no special status
IUCN Red List of Threatened Species: endangered
There are no known adverse affects of Megadyptes antipodes on humans.
Yellow-eyed penguins provide a positive impact on the New Zealand economy because of the tourism industry built upon viewing them. However, the birds are not as cooperative as some other animals involved in ecotourism because they are shy and easily scared by humans. When humans view yellow-eyed penguins, they are required to hide and remain quiet, so the birds are not startled. This ecotourism allows for increased awareness and knowledge about the penguins and helps in their conservation. Ecotourism has a positive effect on the local economy and it helps with the conservation effort. Conservation efforts are partially funded by the fees charged for such tours.
Positive Impacts: ecotourism
Plasmodium relictum is a parasite that has been found on wild yellow-eyed penguins. There is not much information on the ecosystem role of Megadyptes antipodes. Their foraging range is off the continental shelf and they are predators to various fish species. When on land, their only major predators are mammals introduced by humans. They are also prey to New Zealand sea lions, but they are not a major component of the sea lion's diet.
Commensal/Parasitic Species:
Megadyptes antipodes has a diet that consists mostly of small prey, either juveniles or species whose adults are small. Yellow-eyed penguins are carnivores. Their diet is mainly composed of fishes including opalfish Hemerocoetes monopterygius, red cods Pseudophycis bachus, blue cods Parapercis colias, silversides Argentina elongata and spats Sprattus muelleri. However, they also eat mollusks and some crustaceans including Nototodarus sloani and Nyctiphanes australis, respectively. Most of their hunting occurs off the coast of New Zealand at the edge of the continental shelf, making them marine predators. Their foraging behavior depends on the breeding season. Penguins that have not bred successfully travelled greater distances to hunt. Their trips off shore are relatively shorter than trips of other penguins of a similar size.
Animal Foods: fish; eggs; mollusks; aquatic crustaceans
Primary Diet: carnivore (Piscivore )
Megadyptes antipodes is monogamous: a male has one female partner each breeding season. There is a great amount of parental care given by yellow-eyed penguins, which contributes to the monogamous mating system. This species exhibits sexual dimorphism, a difference in secondary characteristics between males and females, responsible for mate selection. In M. antipodes, the sexually dimorphic characteristic is the yellow plumage feathers found on males, females use the color for mate selection. This color pattern is believed to be indicative of mate quality; however, more evidence is required to determine how mates are chosen. Megadyptes antipodes exhibits nesting behavior that influences the social structure of the birds. Their nesting sites are typically very large and isolated. Research indicates that the more isolated the nesting site, the more effective the breeding. Most of their nesting sites are under the cover of surrounding plants, the optimal setting is a coastal forest. These isolated nests are one factor that prevents yellow-eyed penguins from being colonial birds.
Mating System: monogamous
Megadyptes antipodes is a relative of crested penguins and has similar reproductive behavior. Yellow-eyed penguins reproduce during the same breeding season, every year. Their breeding season starts in the middle of August and typically lasts 28 weeks. During this time, penguins find a mate and build a nest where they will lay and incubate their eggs. This species lays only two eggs each year, this is a characteristic shared with other crested penguins. These eggs are laid at the same time, usually in September and October. Unlike many other penguin species, yellow-eyed penguins lay two similarly sized eggs that will both yield viable offspring. In contrast, many penguin species lay eggs of two different sizes. Since both eggs will yield viable offspring, they must incubate both. This is likely due to the amount of the hormone prolactin that is secreted. Once the eggs are laid, they take an average of 43 days to hatch; hatching typically occurs in November, after the incubation period. Juvenile yellow-eyed penguins usually reach sexually maturity after two to three years for females and three to four years for males.
Breeding interval: Yellow-eyed penguins breed annually.
Breeding season: Yellow-eyed penguins breed August through March.
Range eggs per season: 2 to 2.
Range time to hatching: 38 to 54 days.
Average time to hatching: 43 days.
Range fledging age: 3 to 4.5 months.
Average fledging age: 3.5 months.
Range age at sexual or reproductive maturity (female): 2 to 3 years.
Range age at sexual or reproductive maturity (male): 3 to 4 years.
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Parental care in Megadyptes antipodes is displayed by both the male and female parent. Parental care can be seen in yellow-eyed penguins starting at the incubation period, through the growing of the juvenile, until it reaches about six weeks old. Both the male and female parent takes part in the incubation period. Once the eggs are incubated and hatch, a new form of parental investment begins, involving the protection of the young and providing the necessary resources for them. This period is known as brooding and usually takes about six weeks. Neither the role of protecting the young, nor finding food is reserved for a specific parent; one parent guards the newly hatched penguins, while the other hunts. After this six week brooding period, parental protection is reduced, but provisioning is increased. Juveniles will ultimately fledge and leave the nest area to provide for themselves.
Parental Investment: male parental care ; female parental care ; pre-hatching/birth (Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female)
Committed to creating natural environments where threatened yellow-eyed penguins can thrive.
The yellow-eyed penguin (Megadyptes antipodes), known also as hoiho or tarakaka, is a species of penguin endemic to New Zealand.[2][3]
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 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.[4]
The yellow-eyed penguin was first described by Jacques Bernard Hombron and Honoré Jacquinot in 1841.
The yellow-eyed penguin is the sole extant species in the genus Megadyptes. A smaller, recently extinct species, the Waitaha penguin (M. waitaha), was described in 2009.[5] A 2019 study recommended classifying the Waitaha penguin as M. a. waitaha, a subspecies of the extant yellow-eyed penguin.[6] The same 2019 study described M. a. richdalei, a recently extinct dwarf subspecies from the Chatham Islands.[6]
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,[7][8] and this will help resolve the origins and aid conservation by helping to inform any future breeding programmes.
The yellow-eyed penguin is most easily identified by the band of pale yellow feathers surrounding its eyes and encircling the back of its head.[9] Its forehead, crown and the sides of its face are slate grey flecked with golden yellow.[10] Its eye is yellow.[2][9] The foreneck and sides of the head are light brown.[2] The back and tail are slate blue-black.[2][10] Its chest, stomach, thighs and the underside of its flippers are white in colour.[2]
It is the largest living penguin to breed on the mainland of New Zealand and the fourth or fifth heaviest living penguin going on body mass.[2][11] It stands 62–79 centimetres (24–31 in) tall and weighs 3–8.5 kilograms (6.6–18.7 lb).[2][12] Weight varies throughout the year, with penguins being heaviest just before moulting, during which they may lose 3-4 kilograms in weight.[13] Males at around 5.53 kg (12.2 lb) on average are somewhat heavier than females at an average of 5.13 kg (11.3 lb).[11][12][14]
Juvenile birds have a greyer head with no yellow band around their eyes.[9]
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.[15]
The yellow-eyed penguin is mostly silent.[2] It makes a shrill bray-like call at nest and breeding sites.[3]
Until recently, it was assumed that yellow-eyed penguins were 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.[5][16] Dr 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."[17]
A dwarf subspecies from the Chatham Islands, M. a. richdalei, is extinct.[6] The modern population of yellow-eyed penguins does not breed on the Chatham Islands.
Today, yellow-eyed penguins are found in two distinct populations, known as the northern and southern populations.[18]
The northern population extends along the southeast coast of the South Island of New Zealand, down to Stewart Island and Codfish Island.[2] It includes four main breeding areas in Banks Peninsula, North Otago, Otago Peninsula and the Catlins. It may also be referred to as the mainland population.[3]
The southern population includes the Subantarctic Auckland Islands and Campbell Island.[18]
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.[19]
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).[20][21] Other species taken are New Zealand blueback sprat (Sprattus antipodum) and cephalopods such as arrow squid (Nototodarus sloanii). However, they also eat some crustaceans, including krill (Nyctiphanes australis).[22] Recently, jellyfish were found to be targeted by the penguins. While initially thought that the birds would prey on jellyfish itself,[23] deployments of camera loggers revealed that the penguins were going after juvenile fish and fish larvae associated with jellyfish.[24]
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.[25] 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.[25] This also means that their average dive depths are determined by the water depths within their home ranges.[26]
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.[27][28] Accordingly, the consensus among New Zealand penguin workers is to use habitat rather than colony to refer to areas where yellow-eyed penguins nest.
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.
First breeding occurs at three to four years of age and long-term partnerships are formed.
The yellow-eyed penguin is considered one of the rarest penguin species in the world.[29] 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.[30]
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.[31]
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.[32][33]
In August 2010, the yellow-eyed penguin was granted protection under the U.S. Endangered Species Act.[34]
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.[35] A similar problem has affected the Stewart Island population.[36] Treatment of chicks in hospital has proven successful with 88% of 41 chicks treated in 2022 surviving.[37]
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.[38]
{{cite web}}: CS1 maint: archived copy as title (link) {{cite web}}: CS1 maint: url-status (link) The yellow-eyed penguin (Megadyptes antipodes), known also as hoiho or tarakaka, is a species of penguin endemic 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 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.
