New Zealand is the penguin capital of the world. Of the 19 species of living penguins, nine breed in New Zealand or its territories, including the Ross Sea sector of Antarctica, and another six are visitors. New Zealand is home to the greatest diversity of penguins, and has more fossil species than any other region. The first and the oldest fossil penguins were found in New Zealand.
Penguins belong to an exclusive family of birds called Spheniscidae. While many groups of waterbirds include one or two flightless species, penguins are the only group in which all members are flightless. This universal loss of flight suggests that, whatever evolutionary event drove the ancestors of penguins to give up flying, the transition to swimming and diving has been enormously successful.
While both flying birds and diving birds are streamlined to minimise the effects of drag in the air or water, the other demands on their bodies are contradictory. Flying birds need to be light, with sufficient wingspan to provide lift to counteract the effects of gravity. In contrast, a diver needs to be dense to offset the buoyancy of water and, for propulsion, the wings need to be short and powerful to move through the denser medium. During the Late Paleocene–Early Eocene period, 50–60 million years ago, the southern seas were temperate to subtropical and offered abundant food to a bird that could dive deep enough.
Successful diving is a function of body size: larger animals have larger oxygen stores and are able to dive deeper and for longer. To get to the deepest fish and squid, the ancestor of penguins needed to become larger. The point at which seabirds with some diving ability became flightless divers was probably when they reached a weight of about 1 kilogram. Beyond that, the contradictory requirements of flying and diving are mutually exclusive: the wingspan that will keep a large bird aloft is too big and fragile for efficient diving.
Once free of the constraints of flying, penguins evolved rapidly into many different species (a process termed radiation by evolutionary biologists), with some becoming much larger. The largest New Zealand fossil penguin ever found, Pachydyptes ponderosus, is estimated to have stood 1.4–1.6 metres tall. In contrast, the smallest known penguins, fossil and living, measure just 40 centimetres in length. This diversity suggests that trading flight for diving made it possible to exploit a range of marine environments, from deep Antarctic waters to subtropical surface and inshore waters.
Of all modern penguins, the large emperor penguin performs the most astounding diving feats. Their regular dives are 100–200 metres deep and last around six minutes, but some have achieved dives of 22 minutes and depths of 565 metres. The dives of little penguins, on the other hand, are usually 10 or 20 metres and last 25 seconds, although depths of 60 metres have been recorded.
Penguins come in many sizes, but one shape fits all. Moving through water requires much more energy than moving through air, as water is denser. For swimming marine animals – whether fish, seal, whale or penguin – a spindle shape has proved the best at minimising the drag.
Penguins’ feet are tucked away at the rear, where they function as rudders. Their feathers lock together to form an insulating cover that directs water over the body with little disturbance.
Experiments in wind and water tunnels show that coefficients of drag for penguins are lower than those for any car. Natural selection may permit penguins to indulge in a yellow crest or two, but not to mess with their basic design. Those that don’t conform are not as efficient, and as a consequence breed less successfully and survive less well.
Penguins are found only in the southern hemisphere. If being a spindle-shaped diver is the best way to exploit the riches of the deep, why are there no penguins in the northern hemisphere?
The answer is twofold. Firstly, flightlessness is only likely to evolve in places free of land-based predators – especially mammalian ones – such as the isolated islands of New Zealand and the subantarctic. In contrast, being vulnerable to the bears, wolves and other predators of the northern hemisphere makes flight too valuable to give up. Secondly, tropical seas are generally too unproductive and the prey too dispersed, creating a barrier to penguins moving further north.
Penguins need food that is concentrated in swarms, such as krill, fish or squid, as they cannot cover large distances rapidly, compared to many flying seabirds. Despite this, some enterprising penguins have got as far north as the equator where the cold, nutrient-rich Humboldt Current reaches the Galapagos Islands, creating upwellings where prey is abundant compared to most of the tropics.
While penguins are supremely adapted for an aquatic existence, they are forced to find a balance between two worlds: the sea for feeding and the land for moulting and breeding. Penguins’ feathers insulate them in the water – much like a diver’s dry suit, trapping a layer of air next to the skin – and they must be renewed annually to maintain their performance. Penguins must remain on land as they moult (shedding their old feathers and growing new ones), which typically takes two to three weeks each year. And to keep eggs and chicks warm and protected from predators, parents must take turns staying on the nest on land.
Penguins nest in a variety of ways. The little penguin makes a burrow in soil, or nests in natural cavities. Others nest in forest or scrub among tree roots and litter, while open stone nests on bare rocky ground suffice for other species.
The emperor penguin avoids land altogether, breeding on winter sea ice and using its feet instead of a nest to hold the egg.
To be a penguin and to be on land – for moulting or nesting – is to be on a diet. All penguins have a remarkable capacity to fast for days or weeks. Emperor penguins hold the record. The males don’t eat from the start of their courtship until the end of incubation: about four months.
How far penguins must travel for food determines how long they spend at sea between visits to the nest. The yellow-eyed and little penguins are inshore foragers, usually staying within 20 kilometres of their colony. Mostly they are at sea for only a day or two. All of New Zealand’s other penguin species are offshore foragers and, especially when the other parent is incubating the egg, can travel tens or hundreds of kilometres to get the fish, krill or squid they need. This can keep them away for two or three weeks. When feeding chicks they cannot range as widely because they need to return frequently to the nest with food.
Penguins face challenges both on land and at sea. One of the consequences of evolving flightlessness during a period free of predators is that you become vulnerable should predators subsequently invade.
New Zealand and other southern islands and land masses with populations of penguins were not visited or settled by humans until the last few centuries. Once discovered, penguins were hunted for their meat, eggs, skin and oil. Although penguins are not directly preyed on by people any longer, things we introduced continue to threaten their survival: predators such as cats, dogs and mustelids; diseases; and habitat destruction.
Clearing the land for farming removes the vegetation yellow-eyed penguins need to shelter their nests. Indirect threats include pollution, overfishing and – perhaps most insidious – global warming. Periods of elevated sea-surface temperatures during the last 20 years have been associated with reductions in the yellow-eyed penguin’s principal prey species, and with toxic algal blooms that have decreased the survival and success of penguins breeding on the Otago Peninsula. Shifts in oceanic zones of high productivity require penguins to swim further to gather food for their chicks, lowering breeding success.
Of the nine species of penguins breeding in New Zealand’s territories, five are listed by the World Conservation Union as vulnerable or endangered. The three Antarctic species are partly protected by their relative isolation. That leaves the little penguin as New Zealand’s least endangered penguin species.
Despite their vulnerability, penguins can be relatively unaffected by well-managed tourism. If encountering penguins in the wild, keep your distance, stay quiet, and do not make sudden movements. Penguins will not come ashore if they are aware of your presence, so you could try taking cover in a hide or vegetation.
Some penguins, including the rockhopper, Adélie and emperor, breed in crowded colonies where there is a constant racket of trilling calls, rather like the din of hooters at a children’s party. Other species, such as the yellow-eyed penguin and Fiordland crested penguin, have lower-density nesting tucked away amongst vegetation for shade and shelter.
The best place to see little penguins is at the Ōamaru penguin colony, where more than 200 come ashore each evening during the peak of the breeding season. For yellow-eyed penguins, the Otago Peninsula offers the best viewing. At the Department of Conservation’s hide at Sandfly Bay you can witness penguins coming ashore in the late afternoon. Fiordland crested penguins are especially shy and perhaps most vulnerable to disturbance. However, keen walkers can find them at a few places on the Fiordland coast.
Penguins probably evolved about 50 million years ago, and New Zealand has yielded clues to their origins.
During a visit to the North Otago coastline, Walter Mantell (whose father Gideon discovered the first dinosaur fossil) acquired a strange bone unearthed from the limestone deposits around Kakanui.
In Britain it came to the attention of Thomas Huxley, the paleontologist as well known for his support of Charles Darwin as for his expertise with old bones. In 1859, the year Darwin published On the origin of species, Huxley published a scientific paper describing Mantell’s somewhat damaged bone as the tarsometatarsal (fused ankle bone) of an extinct penguin, which he named Palaeeudyptes antarcticus (‘ancient winged diver of the south’).
This was a wonderful piece of scientific deduction. Fortuitously for Huxley, the tarsometatarsal is the most distinctive bone that penguins possess, and it is dense – unlike the hollow bones of flying birds. Non-pneumatic bones (without air spaces) are characteristic of penguins and aid their diving by counteracting the buoyancy of water. Unfortunately no other specimens of Palaeeudyptes antarcticus have ever been found. All that is known of the world’s first-discovered fossil penguin species is what can be gleaned from a broken ankle bone in a drawer in London’s Natural History Museum.
From the age of the limestone deposits around Kakanui, it is likely that Palaeeudyptes lived somewhere between 23 and 34 million years ago: not so old by penguin standards, and certainly not by those of birds.
Birds have existed for about 150 million years. Penguins evolved from flying ancestors, and perhaps the best evidence for that comes from Waipara, about 50 kilometres north of Christchurch. Waipara is known for its vineyards, but its sun-baked soils have also yielded treasure from a vintage 55 million years ago: the fossilised bones of a precursor penguin.
From a few brown fragments of shoulder and flipper bones it was possible to deduce that they belonged to a diving bird: the main bone in the flipper is non-pneumatic, and flattened for paddling like those of modern penguins. However, features of flying birds are still writ within its anatomy. The bones are more fragile than a typical penguin’s, and some are shaped like those of some flying birds.
The Waipara specimen – named Waipara penguin (Waimanu tuatahi) – may be a snapshot of an evolutionary event as significant to penguins as the moment when our ancestors began to walk upright: the point at which their ancestors abandoned flight in favour of life in the sea.
The little penguin and the yellow-eyed penguin both breed on the New Zealand mainland.
The little penguin or kororā (Eudyptula minor) is found around New Zealand’s three main islands and the Chatham Islands. Birds in Canterbury populations are often called white-flippered penguins. Little penguins are also found in Australia, where they are often called fairy penguins. Research suggesting that there is a separate species (Eudyptula novaehollandiae) with a population in Otago was in 2016 being considered by the Birds New Zealand Checklist Committee.
Weighing only 1 kilogram, and 40 centimetres in length, little penguins are also named blue or little blue penguins, for the bluish plumage on the upper parts of the body. They are largely nocturnal on land, coming ashore after sunset. Their posture is tilted further forwards than the upright stance of other penguins.
Little penguins nest in burrows, caves, rock crevices and, more rarely, under bushes and trees, around virtually the entire coastline. The breeding season varies but usually begins somewhere from late June to September. Typically, two eggs are laid, three days apart. Sometimes a second clutch is laid after the first chicks have fledged.
The strongholds of the yellow-eyed penguin or hoiho (Megadyptes antipodes) are the subantarctic Auckland Islands and Campbell Island, where over 1,000 individuals breed at each site. They also breed on mainland Banks Peninsula, and from Ōamaru south to Foveaux Strait and the nearby islands, including Stewart and Codfish islands.
Codfish Island, to the west of Stewart Island, is the only place where you can find all three species of New Zealand’s mainland penguins – the yellow-eyed, little and Fiordland crested penguins. But don’t think that it is the perfect place to observe penguins: the island is out of bounds to people for the recovery of the flightless native parrot, the kākāpō.
This large penguin is about 76 centimetres long and weighs around 5 kilograms. It has yellow eyes, and stripes of yellow feathers from the eyes to the back of the head.
It is unusual in that it nests under dense vegetation – traditionally in forest – for protection; it is also the least social of all penguins. Nests are separated by tens and often hundreds of metres. The penguins remain year round at their breeding sites, feeding largely on fish found close inshore. Dependent on vegetative cover and a localised food source, they are particularly vulnerable on the mainland where much of the forest has been cleared for farming. Other comparatively recent factors such as overfishing, introduced predators and global warming have wreaked havoc with their breeding success. Although they are often cited as the world’s rarest penguins – recent estimates suggest there are between 3,500 and 5,000 individuals – the Galapagos penguin is probably even more endangered.
New Zealand is significant in the evolution of crested penguins – four of the world's eight species breed there, three exclusively. A fifth species, the royal penguin, Eudyptes schlegeli, breeds on nearby Macquarie Island. Macquarie Island is in the same geographic group as New Zealand's subantarctic islands, but is administered by Australia.
Crested penguins are distinguished by crests of yellow feathers above the eyes that look like unruly eyebrows. The length and shape of the crest is peculiar to each species.
These penguins present one of biology’s great unsolved mysteries. They are known as obligate brood reducers – they lay two eggs but only fledge a single chick. Furthermore, the second egg is much bigger than the first, and it is usually from this that the successful chick hatches.
Tracking the penguins with satellites and global positioning systems reveals that they forage offshore, tens and even hundreds of kilometres from the colony. It may require too much energy to transport food for two chicks over such a distance – which could explain why the adults rear only one chick, but not why they lay two eggs.
The Fiordland crested penguin or tawaki (Eudyptes pachyrhynchus) is found around the south-western coast of the South Island, Stewart Island and associated offshore islands. Fossil remains show that this species once occurred around the South Island and probably also on the North Island, so some call it the New Zealand crested penguin.
Around 67 centimetres long and weighing about 4 kilograms, they nest in dense rainforest. They eat squid, fish and crustaceans, feeding on the narrow continental shelf out from the western coast during breeding.
This species (Eudyptes robustus) is restricted to the tiny Snares island group. A slightly larger version of the Fiordland crested penguin, at about 65 centimetres and 3 kilograms, it is distinguished by a fleshy margin at the base of its bill.
The erect-crested penguin (Eudyptes sclateri) is largely restricted to the Antipodes Islands and Bounty Islands, with a few isolated pairs breeding on the Auckland Islands. A relatively solid medium-sized penguin at 5.4–6.4 kilograms and 68 centimetres, its crest of yellow plumes is strikingly upright when dry on land.
The eastern rockhopper penguin (Eudyptes filholi) breeds on islands in the subantarctic Pacific and Indian oceans, and the related western rockhopper penguin (Eudyptes chrysocome) on islands in the subantarctic Atlantic Ocean and around Cape Horn. They are the smallest of the crested penguins, at 61 centimetres and 2.5 kilograms. The slightly larger Moseley's rockhopper penguin (Eudyptes moseleyi) breeds further north on islands in the South Atlantic and Indian oceans. Within New Zealand, eastern rockhopper penguins breed on the subantarctic Campbell, Auckland and Antipodes island groups.
The Adélie penguin (Pygoscelis adeliae) has a circumpolar distribution confined to the Antarctic, where it breeds on the shores and off-lying islands. Within the New Zealand-claimed Ross Sea sector, there are colonies breeding on Ross Island and north along the western coastline of the Ross Sea to Cape Adare, the largest Adélie penguin colony in the world.
Medium-sized at 71 centimetres and 5 kilograms, these are the classic tuxedoed black and white penguins, with the distinctive white eye ring.
The chinstrap penguin (Pygoscelis antarctica) is a member of the same genus as Adélie penguins, and also confined to the Antarctic. They are mostly concentrated around the Antarctic Peninsula, with an anomalous few breeding on the Balleny Islands in the Ross Sea sector.
Similar in body mass to an Adélie, although a little longer at about 77 centimetres, they are recognisable by their white faces and a thin black line running under the chin. Like Adélies, they feed almost exclusively on krill.
In July 2011 a disoriented emperor penguin was discovered on Peka Peka beach, north of Wellington, more than 3,000 kilometres off course from Antarctica. When he fell ill after eating sand and driftwood he was operated on by Wellington Zoo vets. After recovering, Happy Feet, as he was dubbed, was released in the Southern Ocean. The tracking device he was wearing stopped broadcasting after a week, so his fate is unknown.
The emperor penguin (Aptenodytes forsteri) breeds in Antarctica, in winter, on stationary sea ice. There are colonies at Cape Crozier (Ross Island), at Beaufort Island, and along the western margins of the Ross Sea at Cape Washington.
Emperors are the largest of all living penguins, about 112 centimetres long and 30–38 kilograms in body mass. They (and the closely related king penguin) differ from other penguins in that they lay only a single egg, incubated on their feet rather than in a nest.
Six other penguin species have been recorded as visitors to New Zealand:
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