Penguins are a unique group of flightless seabirds that are at home on land and in the sea. They are covered with a waterproof coat of dense, short and flattened feathers, and their wings are modified into flippers. On land they walk upright, standing up to one metre high, and in water they can swim rapidly and dive for food.
Fiordland crested penguin / tawaki
Thirteen of the world’s 18 penguin species have been recorded in the New Zealand region (including the Ross Dependency). Nine of these species breed here.
Three penguin species breed on the New Zealand mainland, they breed alone or in small groups:
Their Antarctic relatives gather in large colonies:
Although the penguin’s ancestors were flying birds, penguins do not have this skill and they instead use their paddle-like wings (flippers) to propel themselves through the water.
Penguin wing bones are solid, unlike flying birds’ wings which are hollow to save weight.
Penguins dive to catch food, including fish, krill (tiny shrimp-like creatures), squid and a wide range of marine invertebrates. The emperor penguin holds the diving record at 450 metres deep and 11 minutes underwater.
Penguins feed their young by storing fish in their stomach and regurgitating it. This means adults not only have to catch enough fish for themselves; they also must slow the digestion process to ensure that their chicks get a meal once they arrive home.
Unlike flying birds, which moult and replace their feathers gradually so that they can continue to fly, penguins moult all of their feathers at once. This enables them to go back out to sea without ‘leaks’ in their waterproof insulation. Moulting is a stressful time for penguins, and during this two to five week period in late summer birds may look sick and ragged. They are also highly vulnerable to predators at this time.
Snares crested penguin
Small population sizes, restricted geographical ranges, predators and habitat degradation all contribute to the vulnerability of mainland New Zealand penguin species.
The main land-based predators are stoats, ferrets, rats, dogs, and feral cats. Penguins are also highly susceptible to human disturbance when nesting.
The yellow-eyed penguin is the New Zealand species most affected by habitat loss. A forest or shrubland nesting species, the yellow-eyed has come under pressure as forest has been replaced with pasture.
A slight warming of sea temperatures in the past 50 years, which is thought to have forced vital food species such as krill further south.
Fisheries by-catch of penguins, especially when gill nets are used. Entanglement in nylon fishing line discarded by recreational fishers is also a threat to penguins.
Spills of light fuel oil from fishing boats and the emptying of engine-room bilges. The oil coats penguins’ feathers and prevents them from insulating properly. Fortunately, these incidences are rare around New Zealand.
Sharks, seals, sea lions and occasionally orca prey on penguins while at sea. Leopard seals, usually residents of the Antarctic region, are specialist penguin predators and NZ sea lions occasionally dine on penguins. Fur seals rarely do.
Skua (a large gull-like bird) and giant petrels are the penguin’s only avian predators and will both take poorly guarded eggs and chicks. Skua are also capable of killing adult blue penguins.
Yellow-eyed penguin / hoiho
You can help
These species breed alone or in small groups, unlike their Antarctic relatives that gather in large colonies.
Keep dogs away from penguin colonies and do not disturb nesting sites. Do not leave old fishing line on beaches or throw it into the sea.
Report any penguin sightings to the local DOC office and gain professional advice before disturbing a bird, even if you think it is sick. In many instances, these birds are simply moulting.
You may want to donate your time or money to help non-profit organisations and voluntary groups who work to protect penguins. Groups active in penguin protection include the Yellow-eyed Penguin Trust and Forest & Bird.