Snares crested penguin
Snares crested penguins diving from shore. Source: Mila Zinkova
Also called the Snares Island penguin, the Snares crested penguin (scientific name: Eudyptes robustus) is one of seventeen species of flightless birds in the family of penguins. It is one of six "Crested Penguins" in the genus Eudyptes which also includes the Fiordland crested, Rockhopper, Macaroni, Snares crested, Royal and Big-crested penguins..
 Source: Thomas Mattern/Wikipedia |
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Conservation Status  |
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Scientific Classification Kingdom: Animalia |
Like all penguins, the Snares crested penguin is characterized by its erect posture, stiff wings (flippers), excellent swimming ability, awkward movement out of water, and coloring. The black back and white front, make penguins difficult to see when swimming, blending against the sea from above and the sky from below.
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Physical Description
This medium-sized species has the immediately recognizable pattern of most penguins of snowy-white underparts and dark blue-black upperparts, head and throat. The Snares crested penguin's most noticeable feature is a bright yellow, thin, bushy crest running above and behind each eye. The red-brown bill is very robust, particularly in the male, and the conspicuous bare pink skin at its base helps distinguish the Snares from the similar Fiordland penguin.
As with the other five species of Eudyptes, the Snares crested penguin has characteristic yellow plumes or crests on the head. Eudyptes robustus stands between 50 and 60 centimeters tall. They are physically similar to the Fiordland penguin (Eudyptes pachyrhynchus). They have a thick heavy bill, with white or pink skin around the base of the beak. They have all black feathers on their cheeks as opposed the white feather tufts on the cheek of the Fiordland penguin. The Snares crested penguin has broad crests that grow from the beak to the back of the head. Males and females are physically very similar, however the male is usually a little taller and weighs a little more.
Reproduction
There are around 135 breeding colonies for Snares crested penguin on Snares Island, with approximately two nests per square meter. These colonies produce an average of 44 fledglings per year.
Breeding begins around the age of six, with males returning to the breeding colony in August, and females following shortly after. Single males attract females by standing upright with their wings extended and repeatedly pumping their chests. The reproductive cycle begins in the first three weeks of September.
The nests are created by digging shallow holes in the ground. These holes are lined with twigs and small branches. Snares crested penguins build nests under trees and shrubs to shield themselves from the sun. If the vegetation is destroyed by storms the breeding grounds are moved.
Two eggs are typically laid in late September to early October, the first, smaller egg being laid four to five days before the second, larger egg. Both parents take turns incubating the eggs for the first 10 days. At this point the male goes to the ocean to feed the female who incubates the eggs for twelve days straight. When the male returns, the female goes to the ocean to feed and the male incubates the eggs for the next eleven days. A mutual display of bowing and trumpeting (extending the beak vertically in the air and calling out) is performed when the male returns to the nest, helping to cement the bond.
For the first three weeks after hatching, the male stands guard, protecting the chicks from predators, while the female forages and returns daily to feed the young. As with most penguins, both chicks rarely survive, with many pairs losing an egg during incubation, or one chick usually dying before the end of the guard stage. This high mortality rate is due to weather, primarily rainstorms. Predation and parasites are not significant sources of mortality.
After the guard stage, the chick begins to explore its surroundings, creching with other nearby chicks, but returning to the nest to be fed. At 11 weeks the young fledge. Little has been recorded on the diet of the Snares crested penguin, but krill, squid and fish are known to be included.
Behavior
Snares crested penguins show three types of behavior: general, aggressive, and sexual. General behaviors include huddling, in which the birds gather together to minimize heat loss, and preening, in which the bird gathers oil from a preening gland on the rump and applies it to the feathers. This is done to maintain the feathers and prevent water infiltration.
Aggressive behaviors include point and gape, in which the penguin points at an intruder and opens his bill, growling, to warn intruders that they are entering that penguin's territory. Another aggressive behavior is charging, in which the bird charges the intruder with its wings extended and beak open. This can be done silently or with a growl.
Sexual behaviors include the ecstatic display, in which the bird stands up right with its wings extended. The bird then repeatedly pumps its chest. This is done by single males to attract females. Bowing is done in pairs when the male returns to the nest. The female will bow to the male and then the male will bow to the female. The mutual display and trumpeting are both acts done when the male returns from an extended absence. These two behaviors are very similar. In the mutual display, the returning male will face the female, bow, and then extend his beak vertically in the air and call out. The female will then repeat the act. Trumpeting is the same act as the mutual display, except it is done with the pair standing side by side.
Distribution
Breeding is confined to the Snares Islands off southern New Zealand, but the wintering range is largely unknown, although occasional records exist from the waters off Tasmania and South Australia.
Habitat
Snares crested penguins live in the temperate sub-antarctic sub-zone. This habitat provides sufficient vegetation for nest building and roosting. Snares Island is heavily forested, but the shores are rocky with mosses filling in the gaps. The main rock type is muscovite granite. The ground is cover to a depth of two meters with peat. It is on this type of substrate that the Snares Island penguins construct their nests.
Nests are typically constructed in dense colonies in muddy, forested areas and on rocky slopes, with these colonies often shifting to new sites, as the vegetation is killed off by successive breeding and nesting activities.
Food Habits
The diet of the Snares Island Penguin is not well known, however, researchers believe that it is made up of krill, squid, and fish. Fish makes up approximately 18 percent of its diet.
Conservation Status
At present, there are few conservation issues facing the Snares crested penguin. All 17 species of penguins are legally protected from hunting and egg collecting. There are no introduced land predators on Snares Island, however, researchers believe that the introduction of the Norwegian rat (Rattus norvegicus) could pose a significant problem.
At present the only predators of adultSnares crested penguins is the Hooker's sea lion. Eggs and chicks are subject to predation by brown skuas and giant petrels. Because the population is restricted to Snares Island, there is no imminent danger from human contact.
Due to concern about the accidental introduction of predators, the Snares Islands have been designated as nature reserves and part of a World Heritage Site, with landing by permit only. This species is also protected by the New Zealand government. Classified as Vulnerable (VU) on the IUCN Red List 2006.
Threats
Although no major threats currently face the Snares crested penguin, the species is considered vulnerable due to its breeding population being confined to one small island group. The Snares Islands are completely free of introduced predators and any accidental introduction could be disastrous. Additionally, waters surrounding these islands are the target of a large squid fishery, which may be reducing the penguin's available prey. Other related species within the region, notably the erect-crested penguin (E.Âsclateri) and Rockhopper penguin (E.Âchrysocome), are known to be undergoing major declines, possibly due to oceanic warming and the resultant redistribution of prey species.
Economic Importance for Humans
Because Snares crested penguin has almost no contact with humans, it has no significant positive or negative impact on humans.
References
- Eudyptes robustus Encyclopedia of Life (accessed March 26, 2009)
- Species 2000 & ITIS Catalogue of Life: 2009 Annual Checklist. Bisby FA, Roskov YR, Orrell TM, Nicolson D, Paglinawan LE, Bailly N, Kirk PM, Bourgoin T, Baillargeon G., eds (2009), Species 2000: Reading, UK.
- Eudyptes robustusBellows, N. 2001. The Animal Diversity Web (online). (accessed March 11, 2009)
- Snares Penguins International Penguin Conservation Work Group (accessed March 26, 2009)
- Snares-crested penguin New Zealand Penguins (accessed March 26, 2009)
- Snares Penguin BirdLife International (accessed March 26, 2009)
- WoRMS, World Registry of Marine Species (accessed March 26, 2009)
- IUCN Red List (accessed March 26, 2009)
- Global Register of Migratory Species (accessed March 26, 2009)
