Eudyptes robustus

Geographic Range

The Snares crested penguin ( Eudyptes robustus ) is found in the Australian region of the world. This location is found south of the Tasman Sea, on the mainlands of New Zealand. The Snares crested penguin is not a migratory bird, so it is only native to the mainlands of New Zealand, a wide range around New Zealand in the Pacific Ocean, and 200 km south of New Zealand on Snares Island.

• Biogeographic Regions
• australian australian
  • native native
• pacific ocean pacific ocean
  • native native

Habitat

Snares Island has wet subantarctic conditions and its habitat including the southern ocean and forests. The Snares crested penguin's habitat is also made up of rocky shores located underneath forest that inhabit the island. The penguins can be found on bare rocks, open areas surround by tussock grass, forest, or under the canopies of Olearia iyallii , Brachyglottis stewartiae , and Hebe elliptica . This helps provide a sturdy nesting ground for the penguins. The forest also helps provide items to build nests including twigs, pebbles, peat, leaves, and grass.

• Habitat Regions
• terrestrial terrestrial
• saltwater or marine saltwater or marine

• Terrestrial Biomes
• forest forest

• Aquatic Biomes
• coastal coastal

Physical Description

The Snares crested penguin has a distinct physical appearance, with a white ventral region and a dark blue-black dorsal region, which includes the head and the throat of the penguin. The penguin also has an identifying characteristic, which is a bright yellow, thin, bushy crest that is right above and behind each eye. The bill of the penguin is red-brown, with a bare pink base that distinguishes the Snares crested penguin from its closest relative the Fiordland penguins ( Eudyptes pachyrhynchus ). In males, the bill is larger than the females. Males (3.4 kg) are also larger than females (2.8 kg). The average length of males and females ranges from 50 to 60 cm.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Reproduction

Mating season for the Snares crested penguin starts in September and ends in February. During the first three weeks of September, the males show up to the island, a week before the females arrive. The male penguins that are looking for a mate will attract the females by standing upright with their wings extended and they repeatedly pump their chest.

Snares crested penguins are monogamous, each pair laying two eggs. If a fatality occurs, the surviving penguin seeks a new mate. However, the second monogamous pair will have a less successful reproduction rate across time. According to Williams and Rodwell (1992), numerous studies report that reproductive success is greater in pairs that reunite in successive seasons rather than newly-established pairs. Advantages for reuniting includemate familiarity, better coordination of breeding effort, and not having to compete for a mate again. Once the penguins do find their mates, they then work together to build a nest made of peat, twigs, stones, and bones that is usually lined with mud.

• Mating System
• monogamous monogamous

As the Snares crested penguin reaches sexual maturity at 4 to 8 years old. The Snares crested penguin breeds once yearly at the start of breeding season (September). For these penguins, the number of offspring produced in a successful season is 2 eggs, but in most circumstances only one of the chicks will survive past the incubation and guard stage. The guard stage is when the male penguin “guards” the chicks while the female forages for food to feed them. The eggs are laid late September into early October with the first egg being smaller and hatching 4 to 6 days before the second, larger egg.

The eggs will incubate for 31 to 54 days, and newborn chicks are 102.1 - 130.4 g. As early as 4 weeks to as late as 16 weeks (average is 11), the chicks can start to fledge. During this period they will molt, losing their baby fluff, and gaining adult feathers that protect them from the cold. This is the period where the fledglings will explore more vigorously becoming more independent until the penguin reaches maturity.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

In the first two weeks after being laid, the eggs are incubated by both male and female but the female will be the one to primarily contribute to the incubation. The male will leave and forage for the first two weeks post egg-laying, leaving the female to incubate both of the eggs by herself. After the male returns, the female then has her turn to feed. The male will stay and incubate the eggs for about a week while the female forages. The female will return from foraging in time for the eggs to be hatched. When pairs that have been separated during foraging bouts are reunited, they will greet each other with trumpeting and bowing. In the first three weeks after hatching the male watches over the chicks, guarding them. During the “guard period”, the female will forage to return and feed the chicks every day. Both chicks usually do not survive partially due to egg-dimorphism. The second egg weighing an average of 130.4 grams, and the first egg averages 102.1 grams. The chick that does not survive usually does not make it past the incubation or guard stage. After the guard stage the chick will creche, exploring with other chicks in small groups until the chicks reach 11 weeks old. At 11 weeks old they are considered fledglings, which is the period where they will molt, learn, and explore reaching there independence. In these years of independence they will learn to hunt and swim until they reach their mature breeding age.

• Parental Investment
• altricial altricial
• male parental care male parental care
• female parental care female parental care
• pre-fertilization
  • provisioning
  • protecting
    • male
    • female
• pre-hatching/birth
  • provisioning
    • male
    • female
  • protecting
    • male
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • male
    • female
  • protecting
    • male
• extended period of juvenile learning

Lifespan/Longevity

The average lifespan of the Snares crested penguin is 15 to 20 years. The percentage of mortality among chicks is 50% to 90%, with most deaths occurs during the first 3 weeks after the chick has hatched. The annual mortality rate among adults is 50%. The Snares crested penguins are not kept in captivity.

Behavior

Typical behaviors by these penguins are huddling and preening. Huddling is what the penguins do to minimize loss of heat in their bodies. Preening is when the penguins gather oil from their preening gland on the rump and applies it to their feathers to maintain the feathers and keep water from penetrating through.

Aggressive behavior is shown when there is an intruder. The Snares crested penguin will do a point and gape; here the penguin will point its bill at an intruder and open its bill, then will proceed to growl to warn the intruder that it is entering a territory. This penguin also can charge the intruder with its wing extended completely and its beak open.

The behavior that the Snares crested penguin will display when attracting a mate is called ecstatic display. The male penguin will stand up straight with its wings extended, repeatedly pumping its chest. Bowing and trumpeting is a sexual behavior displayed in pairs. Bowing occurs when males return to the nest, and is presented mutually between male and female. Trumpeting is displayed when a male is away for extended amount of time, extending his beak calling out to the air receiving the same response from the female.

• Key Behaviors
• terricolous
• natatorial natatorial
• diurnal diurnal
• motile motile
• migratory migratory
• territorial territorial
• social social
• colonial colonial

Home Range

Home range has not been reported for this penguin.

Communication and Perception

The only information found on communication for the Snares crested penguins is the recognition of chicks, as well as the chicks recognizing their mother. According to Proffitt and McLean (1990), chicks were more responsive to their mother’s calls than any other adult penguins. Calls were more effective with the chicks than visual signals, and their nest were used as a meeting place during the creche stage. The creche stage is where a small group of chicks ranging from 3 to 20 chicks group together unattended while both parents forage at sea. When the parents return the chicks recognized their mother’s calls not only at the meeting site, but from any other site as well.

Mated pairs and potential mates communicate via visual displays (initially by the male). The male penguin will stand up straight with its wings extended, repeatedly pumping its chest. The mated pairs can respond to one another visually by bowing, or acoustically by trumpeting.

Most aggressive encounters are visual displays and chases, with very little tactile responses.

• Communication Channels
• visual visual
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Due to the carcasses found in the penguins stomach including fish otoliths and cephalopod beaks, it is believed that the Snares crested penguins' diet consist of crustaceans, fish, and cephalopods. The dominant food source brought in by the penguins consist of krill Nyctiphanes australis . Over a 120 year period the food source for the Snares crested penguin has been stable enough for a significant change not to occur.

• Primary Diet
• carnivore carnivore
  • eats non-insect arthropods
  • molluscivore molluscivore

• Animal Foods
• fish
• mollusks
• aquatic crustaceans

Predation

There are only three predators known to the Snares crested penguin. The Hooker's sea lion ( Phocarctos hookeri ) is the largest predator to the Snares crested penguin, consuming mainly adult penguins. Eggs and small chicks are preyed on by brown skuas ( Stercorarius antarcticus ) and giant petrels ( Macronectes giganteus ). The adult Snares penguin uses their aggressive behavior to warn the penguins in their territory also displaying this behavior as a defense mechanism.

Ecosystem Roles

Snares crested penguins play an important role in the ecosystem. They serve as predators to small fish, krill, and squid while serving as an important prey to Hooker's sea lions ( Phocarctos hookeri ), brown skuas ( Stercorarius antarcticus ), and giant petrels ( Macronectes giganteus ).

Snares crested penguin also serve as a host for common parasites including two species of seabird ticks ( Ixodes auritulus zealandicus and Ixodes uriae ) and four species of seabird lice ( Austrogoniodes concii , Austrogoniodes cristati , Austrogoniodes hamiltoni , and Austrogoniodes macquariensis ). The parasites can cause severe to little health damage to Snares crested penguins.

Economic Importance for Humans: Positive

Snares crested penguins are a potential ecotourism attraction, though they are only viewed from afar. Due to the laws in place protecting the penguins, boats cannot dock on the island. They are viewed from ships from October to February.

Because Snares crested penguins have little to no direct contact with humans, their potential for research as a control species for human disturbance questions is high.

• Positive Impacts
• ecotourism ecotourism
• research and education

Economic Importance for Humans: Negative

Snares crested penguins do not have any negative economic effects on humans.

Conservation Status

Snares crested penguins are listed as "Vulnerable" on the IUCN Red List due to the small island to which they are confined during the breeding season. They are protected by international conservation laws that protect their eggs and the penguin from being hunted and collected. The islands are protected by the New Zealand government, as it is a nature reserve, and part of a World Heritage Site. A World Heritage Site is a natural or man-made site that is considered to be of extreme international importance and is deserving of special protection decided by the organization of UNESCO. Also, due to the restrictions from the island, humans pose no threat towards the Snares crested penguins.

There are a few threats that do contribute to the status of the Snares crested penguins. The major threat include commercial fisheries, oceanographic changes, and oil spills. There have been no new introductions of predators, but there is still a concern that there is a possible accidental introduction of mammals. Due to the large amount of squid around the island there is possible competition between fisheries and the penguins. There is a concern with Snares crested penguins, due to other Eudyptes species that are experiencing major declines possibly caused by ocean warming and change of prey species.

There are conservation actions that are being proposed for the Snares crested penguin. The actions include using a census of all breeding colonies during the incubation period, doing complete regular counts of the penguins every 10 years to track trends in the population, and using the World Heritage Site territorial seas as barrier, out to 19.3 nautical km (12 nautical miles), which would restrict all fishing and turn it into a marine reserve.

Additional Links

Encyclopedia of Life

Contributors

Angelina Fisher-Hewett (author), Radford University, Cari Mcgregor (editor), Radford University, Zeb Pike (editor), Radford University, Karen Powers (editor), Radford University, April Tingle (editor), Radford University, Jacob Vaught (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

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