Penguins (Family Spheniscidae)
David Thompson, Peter Moore, and Taoho Patuawa
General Description
Penguins are members of the family Spheniscidae, within the order Sphenisciformes, and are all flightless birds restricted to the southern hemisphere, predominately at higher latitudes. The closest affinity of these birds is with the order Procellariiformes. Their biology and physiology is highly adapted for swimming and diving, including non-pneumatic and reduced airsacs of their bones and highly specialised feathers. The size of penguins ranges from the largest emperor penguins, Aptenodytes forsteri, at 1.3 m tall and 35 kg, to little penguins, Eudyptula minor, at 45 cm and 1 kg.
Diving abilities vary-the larger species dive to hundreds of metres and can stay submerged for up to fifteen minutes. Hunting is largely visual and may be aided with echolocation. While foraging, penguins can travel 7.4 km/h, with 30% of their time spent travelling. Most of the species forage in the cold southern seas, and feed on krill, cephalopods, and small fish.
Most species synchronously breed once a year, either in spring or summer, with the exception of the emperor penguin, which breeds over winter. First breeding for most species occurs after two years. Breeding is monogamous, with pair bonds long-lasting, in some cases lifelong. Breeding colonies can be made up of widely spaced nests, or dense aggregations of thousands of individuals. Clutches tend to be one to two eggs, but in some species it is rare to rear two chicks. Fledglings are independent from parents at six weeks to six months, depending on the species. The breeding cycle of the king penguin, Aptenodytes patagonicus, lasts longer than a year. Adult survival is somewhat lower than most other seabirds.
Of the seventeen world species of Spheniscidae, six species breed in New Zealand (ie, 35%), while another eight species are visitors to the region. In total, this accounts for 82% of the world's penguin fauna occurring in New Zealand's exclusive economic zone. There is one endemic genus, with a single species - the yellow-eyed penguin, Megadyptes antipodes - and three other endemic species.
Status
Two New Zealand species are "endangered" according to the IUCN classification system: the erect-crested penguin, Eudyptes sclateri, population is regarded to have declined over 50% in the last 45 years to c.50,000 pairs; and the yellow-eyed penguin (5900-7000 birds) has had extreme fluctuations in the past. Conservation measures on the South Island may have halted the decline in habitat quality and the species may be downlisted to vulnerable or near threatened. The Department of Conservation lists the endemic subspecies of little penguin, the white-flippered penguin, Eudyptula minor albosignata, as "nationally vulnerable", because of a human-induced population decline of up to 70% between the years 1980 and 1993.
There are three species (two endemic) that are considered "vulnerable" by the IUCN classification. The Fiordland crested penguin, Eudyptes pachyrhynchus, has an estimated population size of 2500-3000 breeding pairs, and has a limited breeding range along the southwest region of the South Island and Stewart Island. The Snares crested penguin, E. robustus, has a total population size of approximately 54,000 birds. The total world population of the eastern subspecies of the rockhopper penguin, Eudyptes chrysocome filholi, has undergone a 50% reduction since 1940 and a greater than 90% reduction has been documented at some New Zealand colonies. If genetic evidence supports an elevation of this taxon to full species, these populations would be ranked as critically endangered.
The little penguin (including its subspecific taxa in New Zealand, ie, the northern, Cook Strait, southern, and Chatham Island blue penguin) is classified as "least concern" according to the IUCN rankings. Each of these populations has an estimated number of 5000-10,000 breeding pairs.
Key Locations
The erect-crested penguin breeds only at the Bounty Islands and the Antipodes Islands, with possible breeding pairs at the Auckland Islands. The yellow-eyed penguin breeds at eastern South Island locations from Banks Peninsula to Bluff and Stewart Island, and at the subantarctic Auckland Islands and Campbell Island. The white-flippered penguin breeds on Banks Peninsula and Motunau Island.
The Fiordland crested penguin breeds in the southwest region of the South Island and Stewart Island but ranges further to the southern North Island, with occasional sightings in southern Australia and on Chatham Island.
Summary of Threats
For the species that breed on the mainland and offshore islands of New Zealand, introduced mammalian and avian predators pose a risk to eggs, chicks and adults. Habitat destruction also has a major influence on populations. Other human-induced disturbances, such as fire and motor vehicles, can also cause mortality of penguins. These species tend to forage close to shore and are at risk to set nets near breeding colonies and trawl nets, particularly for blue penguins. Oil spills represent another risk for these coastal birds, particularly for colonies that are near ports and harbours. Natural predators, such as seals and sea lions and large fish, are also responsible for mortality.
For species that breed mostly on offshore islands and in the subantarctic, introduced predators are still a threat to the eggs, chicks, and adults. As these species typically forage further at sea, they could be at risk by offshore trawlers and fishing operations, but this risk is considered to be very low for penguins. Competition for fisheries resources between penguins and fisheries has also become a growing concern, particularly in the subantarctic islands.
Typical Habitats
Breeding colonies tend to be in rugged rocky shores, typically on promontories and steep, sloping platforms. Some species nest in caves, overhangs, or burrows, but can also be associated with vegetation, such as tussock grasses. Breeding pairs typically forage near the coast, however they are thought to forage more widely during the non-breeding season. The yellow-eyed penguin is an exception to this, which creates nests in a wide variety of habitats, including large bays, hills, and gullies with sea-facing slopes on rocky shores and sandy or boulder beaches. This species is a resident species, remaining near breeding sites throughout the year.
State of Information
Distribution at sea is poorly known for most species. The range extent for some species (such as the Fiordland crested penguin) may be contracting and is in need of further study.
Significance for Maori
Little is known about significance of penguins to Maori, but evidence from middens shows they were a food source. Korora, the blue penguin, were used as a food source and both parental and young birds were taken during nesting season. Hoiho, the yellow-eyed penguin, has been recognised as a species with particular significance as taonga species to Ngai Tahu of the South Island. The Fiordland crested penguin was called pokotiwha (poko-tiwha) which means "gleaming head', and refers to the highly conspicuous yellow eyebrow crests on the bird's head.
Key References
Birdlife International 2003. Birdlife's online world bird database: the site version 2.0 Cambridge, UK: Birdlife International. www.birdlife.org
Heather, B and Robertson, H. 1996. The field guide to the birds of New Zealand. Penguin, Auckland.
IUCN 2002. 2002 IUCN red list of threatened species. www.redlist.org
Marchant, S and Higgins, P J. 1991. Handbook of Australian, New Zealand and Antarctic birds. Vol. 1: Part B. Ratites to Ducks. Oxford University Press. 1408pp.
Orbel, M. 2003. Birds of Aotearoa. A Natural and Cultural History. Reed Publishing. 198pp.
Taylor, G A. 2000. Action plan for seabird conservation in New Zealand. Part A. Threatened Seabirds. Threatened Species Occasional Publication No. 16. Department of Conservation, Wellington, New Zealand. 233pp.
Taylor, G A. 2000. Action plan for seabird conservation in New Zealand. Part B. Non-threatened Species. Threatened Species Occasional Publication No. 17. Department of Conservation, Wellington New Zealand. 435pp.
Table 4: Penguins (Family Spheniscidae) in New Zealand
| Taxon | Common name | Breeding Species | Endemic Species |
|---|---|---|---|
| Eudyptes chrysocome | Rockhopper penguin | 1 | 0 |
| Eudyptes pachyrhynchus | Fiordland crested penguin | 1 | 1 |
| Eudyptes robustus | Snares crested penguin | 1 | 1 |
| Eudyptes sclateri | Erect-crested penguin | 1 | 1 |
| Eudyptula minor | Little penguin | 1 | 0 |
| Megadyptes antipodes | Yellow-eyed penguin | 1 | 1 |
| Total | 6 | 4 |
Figure 18: Yellow-eyed penguin Megadyptes antipodes annual distribution.
Figure 19: Yellow-eyed penguin Megadyptes antipodes breeding.
Figure 20: Fiordland crested penguin Eudyptes pachyrhynchus breeding.
Figure 21: Erect-crested penguin Eudyptes sclateri breeding.