The Northern Rockhopper Penguin, Eudyptes moseleyi, is a species of penguin. The Rockhopper Penguin Eudyptera chrysocome was split into two species, Northern and Southern Rockhopper Penguin, after research showed differences between the two populations.

A study published in 2009 showed that the world population of the Northern Rockhopper had declined by 90% since the 1950s. For this reason, the Northern Rockhopper Penguin is classified as an Endangered species.

Taxonomy

The Rockhopper Penguin Eudyptera chrysocome was split into two species, Northern and Southern Rockhopper Penguin, after research published in 2006 demonstrated morphological, vocal and genetic differences between the two populations. Analysis of a part of a mitochondrial control region from a Northern Rockhopper Penguin found on the Kerguelen Islands showed that it may have come from Gough Island, 6,000 km away, and that the Southern and Northern Rockhoppers are genetically separate, though some individuals may disperse from their breeding colonies.

Distribution and habitat

More than 80% of Northern Rockhoppers breed on Tristan da Cunha and Gough Island in the south Atlantic Ocean, with the remainder found on Ile Saint-Paul (St Paul Island) and Amsterdam Island in the Indian Ocean.

Ecology and behaviour

Food and feeding

The Northern Rockhopper Penguin feeds on krill and other crustaceans, squid, octopus and fish.

Breeding

It breeds in colonies in a range of locations from sea level or on cliff sides, to sometimes inland.

Population and threats

The current population is estimated to be between 32,000-65,000 breeding pairs at Gough Island, 18,000 to 27,000 pairs at Inaccessible Island, and 3,200 to 4,500 at Tristan da Cunha. In the Indian Ocean, the population was 25,500 pairs on Amsterdam Island, and 9,000 pairs on St Paul Island in 1993; there has been no information available on population trends there since the 1990s. Declines at the Atlantic Ocean sites show a decline of 2.7 per cent per year; the drop in the population at Gough Island has been described as equivalent to the loss of 100 birds every day since the 1950s.

A study published in 2009 showed that the world population of the Northern Rockhopper had declined by 90% 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 Mus musculus and predation and competition from Subantarctic Fur Seals Arctocephalus tropicalis.

The Northern Rockhopper Penguin is classified as Endangered because of the decline in numbers over the last three generations (or 30 years).