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Eudyptes robustussnares penguin

By Angelina Fisher-Hewett

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. (Amey, et al., 2001; Birdlife International, 2012; Hiscock and Chilvers, 2016)

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. (Demongin, et al., 2010; Hiscock and Chilvers, 2016; McLean, 1991; Rafferty, 2016)

  • Range elevation
    130 (high) m
    426.51 (high) ft

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. (Birdlife International, 2012; Hiscock and Chilvers, 2016; Rafferty, 2016)

  • Sexual Dimorphism
  • male larger
  • Range mass
    2.8 to 3.4 kg
    6.17 to 7.49 lb
  • Range length
    50 to 60 cm
    19.69 to 23.62 in

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. (Birdlife International, 2012; Hiscock and Chilvers, 2016; Morrison and Sagar, 2014; Williams and Rodwell, 1992)

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. (Birdlife International, 2012; Hiscock and Chilvers, 2016; Morrison and Sagar, 2014)

  • Breeding interval
    The Snares crested penguins breed once yearly
  • Breeding season
    September to February
  • Range eggs per season
    1 to 2
  • Average eggs per season
    2
  • Range time to hatching
    31 to 54 days
  • Range fledging age
    4 to 16 weeks
  • Average fledging age
    11 weeks
  • Range time to independence
    2 to 72 months
  • Range age at sexual or reproductive maturity (female)
    4 to 8 years
  • Range age at sexual or reproductive maturity (male)
    4 to 8 years

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. (Amey, et al., 2001; Birdlife International, 2012; Morrison and Sagar, 2014; Rafferty, 2016; Williams and Rodwell, 1992)

  • Parental Investment
  • altricial
  • male 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. (Birdlife International, 2012; Croxall, et al., 2012; Rafferty, 2016)

  • Range lifespan
    Status: wild
    15 to 20 years

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. (Birdlife International, 2012; Clark, et al., 2006; Croxall and Davis, 1999; Lamey, 1993; Proffitt and McLean, 1990; Birdlife International, 2012; Clark, et al., 2006; Croxall and Davis, 1999; Lamey, 1993; Proffitt and McLean, 1990)

Home Range

Home range has not been reported for this penguin. (Birdlife International, 2012; Birdlife International, 2012; Croxall and Davis, 1999; Proffitt and McLean, 1990; Rafferty, 2016)

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. (Clark, et al., 2006; Proffitt and McLean, 1990)

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. (Best, 1979; )

  • 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. (Birdlife International, 2012; Lamey, 1993)

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. (Heath, et al., 2011; Mattern, et al., 2009)

Commensal/Parasitic Species

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. (Ellenburg, et al., 2012)

  • Positive Impacts
  • 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. (Birdlife International, 2012; Croxall, et al., 2012; Rafferty, 2016)

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.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

diurnal
  1. active during the day, 2. lasting for one day.
ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

male parental care

parental care is carried out by males

migratory

makes seasonal movements between breeding and wintering grounds

molluscivore

eats mollusks, members of Phylum Mollusca

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

visual

uses sight to communicate

References

Amey, J., D. Houston, A. Tennyson, A. McAllister. 2001. Census of the Snares crested penguin (Eudyptes robustus) breeding population. New Zealand Journal of Zoology, 28/4: 432-433.

Best, H. 1979. Food and foraging behavior of Snares fernbird. New Zealand Journal of Ecology, 6/3: 481-488.

Birdlife International, 2012. "Eudyptes robustus" (On-line). The IUCN Red List of Threatened Species 2012: e.T22697782A40180123. Accessed February 03, 2016 at http://dx.doi.org/10.2305/IUCN.UK.2012-1.RLTS.T22697782A40180123.en.

Brandao, M., J. Moreira, J. Luque. 2014. Checklist of Platyhelminthes, Acanthocephala, Nematoda and Arthropoda parasitizing penguins of the world. Journal of Species Lists and Distribution, 10/3: 562-573.

Clark, J., P. Boersma, D. Olmsted. 2006. Name that tune: call discrimination and individual recognition in Magellanic penguins. Animal Behavior, 72/5: 1141-1148.

Croxall, J., L. Davis. 1999. Penguins: paradoxes and patterns. Marine Ornithology, 27: 1-12.

Croxall, J., S. Butchart, B. Lascelles, A. Stattersfield, B. Sullivan, A. Symes, P. Taylor. 2012. Seabird conservation status, threat and priority actions: a global assessment. Bird Conservation International, 22/1: 1-34.

Davis, L., M. Massaro. 2004. Preferential incubation positions for different sized eggs and their influence on incubation period and hatching asynchrony in Snares crested (Eudyptes robustus) and yellow-eyed penguins (Megadyptes antipodes). Behavioral Ecology and Sociobiology, 56/5: 426-434.

Demongin, L., M. Poisbleau, G. Strange, I. Strange. 2010. Second and third records of snare penguins (Eudyptes robustus) in the falkland islands. The Wilson Journal of Ornithology, 122/1: 190-193.

Ellenburg, U., T. Mattern, D. Houston, L. David, P. Suddon. 2012. Previous experiences with humans affect responses of Snares Penguins to experimental disturbance. Journal of Ornithology, 153/3: 621-631.

Everitt, D., C. Miskelly. 2003. Short note: a review of isabellinism in penguins. Notornis, 50: 43-51.

Heath, A., R. Palma, R. Cane, S. Hardwick. 2011. Checklist of New Zealand ticks (Acari: Ixodidae, Argasidae). Zootaxa, 2995: 55-63.

Hiscock, J., B. Chilvers. 2016. Snares crested penguins Eudyptes robustus population estimates 2000–2013. New Zealand Journal of Ecology, 40/1: 1-6.

Lamey, T. 1993. Territorial aggression, timing of egg loss, and egg-size differences in rockhopper penguins, Eudyptes c. chrysocome, on New Island, Falkland Islands. Oikos, 66/2: 293-297.

Mattern, T. 2007. Marine ecology of offshore and inshore foraging penguins: The snares penguin Eudyptes robustus and yellow-eyed penguin Megadyptes antipodes (Ph.D. dissertation). Dunedin, New Zealand: University of Otago.

Mattern, T., D. Houston, C. Lalas, A. Setiawan, L. Davis. 2009. Diet composition, continuity in prey availability and marine habitat – keystones to population stability in the Snares Penguin (Eudyptes robustus). Emu, 109/3: 204-213.

McLean, I. 1991. A breeding advantage to a passerine living near a penguin colony. New Zealand Natural Sciences, 18: 67-69.

Morrison, K., P. Sagar. 2014. First record of interbreeding between a Snares crested (Eudyptes robustus) and erect-crested penguin (E. sclateri). Notornis, 61: 109-112.

Muller-Schwarze, D. 1984. The Behavior of Penguins Adapted to Ice and Tropics. Albany, New York: State University of New York Press, Albany.

Paredes, R., A. Harding, D. Irons, D. Roby, R. Suryan, R. Orben, H. Renner, R. Young, A. Kitaysky. 2012. Proximity to multiple foraging habits enhances seabirds' resilience to local food shortages. Marine Ecology Progress Series, 471: 253-269.

Parker, G., D. Mock, T. Lamey. 1989. How selfish should stronger sibs be?. The American Naturalist, 133/6: 846-868.

Proffitt, F., I. McLean. 1990. Recognition of parents' calls by chicks of the Snares crested penguin. Bird Behavior, 9: 1-2.

Rafferty, J. 2016. "Snares Penguin" (On-line). Encyclopedia Britannica. Accessed January 29, 2016 at http://www.britannica.com/animal/Snares-penguin.

Williams, T., S. Rodwell. 1992. Annual variation in return rate, mate and nest-site fidelity in breeding gentoo and macaroni penguins. The Condor, 94/3: 636-645.

Zimmerman, K., J. Hipfner. 2007. Egg size, eggshell porosity, and incubation period in the marine bird family Alcidae. The Auk, 124/1: 307-315.

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