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.
