Fiordland crested penguins breed in the rainforests along the rugged coastline of New Zealand's Fiordland and Stewart Island. They nest individually, or in loose colonies, close to the coast. Nest sites are in caves, under overhangs, at the base of trees or in dense vegetation.
The males return to the breeding sites in June (mid winter), usually to the site of last year's nest. The female follows shortly after and two eggs are laid in July. The second egg hatches first, while most first eggs fail to hatch. If both chicks hatch, the smaller first-egg chick is unable to compete for food and usually dies. For the first few weeks of life, the chick is guarded by the male and fed by the female. After this both parents feed the chick and the chick wanders, creching with other chicks if they are nearby, but returning to the nest to be fed.Chicks fledge in November, when they are 10 weeks old. They return to their home colony to breed at around 5 years of age. Juveniles often straggle to the east coast of the South Island, usually to moult.
Little is known about the diet of the Fiordland crested penguin, but it is thought that they feed inshore, particularly during the breeding season. The main prey species reported for Fiordland penguins are cephalopods (85%, mainly Arrow squid), followed by crustaceans (13%, primarily Krill) and fish (2%, mainly Red Cod and Hoki). However, the importance of cephalopods might be exaggerated.
The current status of this penguin is threatened due to its small population. Current population estimates range between 2,500-3,000 pairs and is thought to have declined since the late 1980s by around 33%. It is under threat from introduced predators including dogs, cats, stoats and rats.