Description One of the six species of crested penguin, the rockhopper is circumpolar in distribution. Adults often have white stripes on the cheeks, juveiles have a shorter crest and pale cheeks. One of the smallest of the crested penguins, the rockhopper stands at approx 40cm and weighs up to 4kg. Easily distinguished as adults by their prominent yellow crest and bright red eyes - all other crested penguins have darker eyes. Sexes alike, although males are larger with more robust bills. Juveniles have only a faint crest and have white mottling on the chin and throat. Habitat Inhabitants of the sun-antarctic oceans, the rockhoppers breed in colonies on rocky coasts, often climbing very steep faces to breed under overhangs or caves. Will often breed alongside erect-crested penguins. In the New Zealand region, the rockhopper can be found on the sub-antarctic islands Campbell, Auckland and Antipodes. Juveniles occasionally straggle to the New Zealand mainland. Breeding The males return to their breeding colonies in October, the females following two weeks later. Competition for nest sites can be fierce and fighting is common. A simple nest of stones and vegetation is made and two eggs are laid, however only the second and larger egg is incubated. The chicks fledge in March and the adults return to sea for the winter after moulting in April/May. Diet Little is known of the rockhoppers diet, but it is thought that they are pelagic feeders, dining on fish and krill near the surface. Threats A study published in 2009 showed that the world population of the Northern Rockhopper had declined by 30% since the 1950s, possibly because of climate change, changes in marine ecosystems and overfishing for squid and octopus by humans. Other possible factors in the decline include disturbance and pollution from ecotourism and fishing, egg-harvesting, predation from introduced House Mice and predation and competition from Subantarctic Fur Seals.