Yellow-eyed penguin

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Yellow-eyed penguin
Yellow-eyed penguin (Megadyptes antipodes)

Yellow-eyed penguin ( Megadyptes antipodes )

Systematics
Class : Birds (aves)
Order : Penguins (Sphenisciformes)
Family : Penguins (Spheniscidae)
Genre : Yellow-eyed penguins
Type : Yellow-eyed penguin
Scientific name of the  genus
Megadyptes
Milne-Edwards , 1880
Scientific name of the  species
Megadyptes antipodes
( Hombron & Jacquinot , 1841)
Portrait of a yellow-eyed penguin

The yellow-eyed penguin ( Megadyptes antipodes ) is only in southern New Zealand and to the Auckland Islands and Campbell Iceland widespread Penguin . The yellow-eyed penguin is the only recent representative of its genus. No subspecies are distinguished.

The yellow-eyed penguin, along with the Galápagos penguin and the thick-billed penguin, is one of the rarest penguin species. He is supported by the IUCN as endangered ( endangered ) classified. The reason for the classification is not only the small number of 4800 sexually mature individuals, but also the relatively small breeding area with relatively few breeding colonies. Exceptional events in this region can have a very significant impact on the overall population. On New Zealand's South Island , for example, half of the breeding pairs there died of an illness in 1986 and 1990, and in 2004 50 percent of young birds succumbed to a diphtheria- like respiratory disease.

Appearance

general characteristics

The yellow-eyed penguin reaches a height of 58 to 76 centimeters. As with many other species of penguin, weight varies greatly throughout the year. Males weigh between 4.4 and 8.5 kilograms. Females weigh between 4.2 and 7.5 kilograms. Yellow-eyed penguins reach their maximum weight shortly before moulting , when they have spent several weeks on the high seas after rearing their young. They have their minimum weight after moulting . There is no pronounced sexual dimorphism . Young birds can be distinguished from adult birds up to an age on the basis of their plumage characteristics.

plumage

Resting yellow-eyed penguin

The head, forehead and crown are pale golden yellow with black feather shafts. Black dominates on the vertex, but the proportion varies greatly depending on the individual. The sides of the head, chin and throat are more brownish. A pale yellow band runs from one end of the eye over the back of the head to the other eye. The torso and tail are slate gray. The white underside of the body is sharply set off from the yellowish throat. The wings, shaped into fins, are slate gray on the upper side, but a little darker than the upper side of the body. There is a thin white line on the fin side. The underside of the fin is whitish. The iris is amber to yellow. The upper beak is reddish brown and the lower beak is flesh colored and becomes reddish brown at the end of the beak. The feet are flesh-colored.

Annual juveniles are already largely similar to adult birds. With them, however, the yellow band on the head is less pronounced. The chin and throat are predominantly white and the eyes are pale gray-yellow.

Possible confusion with other penguins

The yellow-eyed penguin can only be confused with a few other penguin species. The yellow-eyed penguin differs from the crested penguins , which occur in the area of ​​distribution of the yellow-eyed penguin, by its longer and narrower beak. It also lacks the elongated facial feathers that are characteristic of this genus.

Not yet sexually mature individuals are less clearly distinguishable from other species. But when compared to similarly sized penguin species, they differ in the lack of noticeable facial markings. Yellow-eyed penguins are also significantly larger than the thick-billed penguins and the little penguins found in the same range .

Distribution area

Breeding area of ​​the yellow-eyed penguin

Yellow-eyed penguins are an endemic species of New Zealand's avifauna . Their breeding colonies are found exclusively in the southeast of New Zealand's South Island . Their range outside of the breeding season is not exactly known. Most adult yellow-eyed penguins overwinter in waters near the breeding colonies. Some individuals, mostly young birds, can also be seen in the Cook Strait .

The main breeding colonies include those on mainland New Zealand, Stewart Island , Campbell Island, and Auckland Island . The breeding colonies are now located in an area that was originally overgrown with stone slices. These have largely disappeared since the colonization of New Zealand by Europeans. Yellow-eyed penguins have adapted to breed in lighter forests, pastures and grassy cliffs. Today they often build their nests between New Zealand flax and the bushy growing Lupinus arboreus .

Food and diet

The main food of the yellow-eyed penguin is fish and, to a lesser extent, cephalopods . Yellow-eyed penguins usually find their food at depths between 20 and 60 meters. They mostly look for their food during the day and mainly use bodies of water near the coast. Most yellow-eyed penguins stay in their breeding colonies during the night. They usually leave at the first light of day and return to the coast between 4 and 7 p.m. During the breeding season, individual birds also search for food for two to three days, but most yellow-eyed penguins return to the breeding colony on the same day. Usually they are no further than 17 kilometers from the breeding colony.

Reproduction

Breeding colonies and aggressive behavior

A yellow-eyed penguin is feeding a young bird
Moulting young bird

The breeding colonies of the yellow-eyed penguins are located in small bays or on headlands of large bays. They nest near the coast on slopes and cliffs sloping towards the sea or under the tree roots of the dense coastal forests of New Zealand. Typically, the nests are located 236 meters from the coastline. The relatively low nest density and the dense vegetation between the nests prevent aggressive behavior, as is typical for many other penguin species. A territory indicating behavior is rare. With this species, calls play a greater role in establishing nesting grounds than is the case with other penguin species. An area within twenty meters of the nest is occasionally defended before the eggs are laid. However, after oviposition, this behavior is concentrated in the immediate vicinity of the nest. One of the aggression gestures of the yellow-eyed penguin is the forward stretching of the neck, the head and beak are stretched far forward and the fins also point forward. In another aggression gesture, the yellow-eyed penguin slowly turns its head from left to right, while staring at the opposing bird, the feathers of the top of the head are slightly raised. In direct disputes, yellow-eyed penguins chop one after the other with their beak and beat their fins.

Clutch

The clutch of yellow-eyed penguins usually consists of two eggs, only for younger breeding birds a clutch consisting of one egg is typical. In birds that are more than three years old, this occurs in only one clutch in a hundred. The laying interval between the two eggs is three to five days. Incubation begins after the second egg has been laid; some pairs delay brooding up to ten days after the clutch has been completed.

In contrast to the crested penguins , there is no obligatory breeding reduction. Yellow-eyed penguins very often raise two chicks. In contrast to the crested penguins, the two eggs do not differ in size. They both weigh an average of 137 and 138 grams. The eggs are oval with smooth, matte shells. Shortly after the eggs are laid, they are bluish to greenish, but then lighten to white over the next 24 to 36 hours. The breeding season lasts 39 to 51 days. Both parent birds are equally involved in the brood. They usually peel off with incubation at two-day intervals.

Fledglings

The two chicks hatch largely synchronously and weigh 108 grams. At the time they fledged, they weighed an average of 5.6 kilograms.

In 63 percent of cases, the second chick hatches on the same day, in 31 percent of cases on the next day. They are cared for by the parent birds for a period of 32 to 63 days. Very short care phases occur especially in the years when the food supply is scarce. On average, the parent birds stay with their young birds for a period of 49 days. For the first 21 to 25 days they are rowed continuously. In contrast to some other penguin species, there is no formation of large groups of children; these so-called “ kindergartens ” are rare in the yellow-eyed penguin and then only include three to seven young birds. The lack of this behavior is probably due to the low nesting density. Most young birds do not move more than ten meters away from their nest, only nine percent of the young birds are still observed at a distance of fifty meters from the nesting site. The parent birds usually return to the breeding colonies in the afternoon or early evening to feed the young birds. They usually find enough food so that one parent bird can raise the fledglings on its own if the second parent dies while rearing young. Years of reduced food availability result in slower chick growth and lower weight by the time they fled. The mortality of the young birds is then above the long-term mean.

The predators of young birds include martens and weasels as well as feral domestic cats . On the high seas, the most important predator is the yellow-eyed penguin, the Barracuda .

Yellow-eyed penguins molt once a year. The moult takes place in February / March and lasts about three to four weeks. They then lose their entire plumage. During this time they are extremely endangered.

Others

Near Taiaroa Head, near Dunedin, there is a privately owned facility that is dedicated to protecting the yellow-eyed penguins that breed on the mainland. Yellow-eyed penguins can be observed on guided tours via a trench system with lookout points.

supporting documents

literature

  • Tony D. Williams: The Penguins . Oxford University Press, Oxford 1995, ISBN 0-19-854667-X

Web links

Commons : Yellow-eyed penguin  album with pictures, videos and audio files

Single receipts

  1. ↑ BirdLife factsheet about the yellow-eyed penguin , accessed November 21, 2010
  2. ↑ BirdLife factsheet about the yellow-eyed penguin , accessed November 21, 2010
  3. ^ Williams, p. 225
  4. ^ Williams, p. 227
  5. ^ Williams, p. 226
  6. ^ Williams, p. 227
  7. ↑ Williams, S: 227
  8. ^ Williams, p. 227
  9. ^ Williams, p. 229
  10. ^ Williams, p. 229
  11. ^ Williams, p. 229
  12. ^ Williams, p. 228
  13. ^ Williams, p. 229
  14. ^ Williams, p. 229
  15. ^ Penguin Place website