The Northern Rockhopper Penguin, Eudyptes c. moseleyi, is usually considered a subspecies of rockhopper penguin, although fairly recent studies show evidence of distinction from the Southern Rockhopper Penguin group Eudyptes c. chrysocome/E. c. filholi.

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

Taxonomy

The Rockhopper Penguin Eudyptes chrysocome is sometimes considered two species, Northern and Southern Rockhopper Penguin, after research published in 2006 demonstrated morphological, vocal and genetic differences between the two populations.^[2][3] Molecular datings suggest that the genetic divergence with the Southern Rockhopper penguin may have been caused by a vicariant event caused by a shift in the position of the Subtropical Front during the mid-Pleistocene climate transition.^[4] 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.^[5] Many taxonomists have yet to recognize the split, although some are beginning to do so.

Distribution and habitat

More than 99% of Northern Rockhoppers breed on Tristan da Cunha and Gough Island in the south Atlantic Ocean.^[6]

Ecology and behaviour

Food and feeding

The Northern Rockhopper Penguin feeds on krill and other sea life such as crustaceans, squid, octopus and fish.^[6]

Breeding

It breeds in colonies in a range of locations from sea level or on cliff sides, to sometimes inland.^[6]

Population and threats

Northern Rockhopper Penguins on Inaccessible Island, drawn by the naturalist aboard HMS Challenger

The current population is estimated to be between 100,000-499,999 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;^[6] the drop in the population at Gough Island has been described as equivalent to the loss of 100 birds every day since the 1950s.^[7]

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.^[8] 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.^[6]

The Northern Rockhopper Penguin is classified as Endangered because of the decline in numbers over the last three generations (or 30 years).^[6]

2011 oil spill

On March 16, 2011, the Maltese-registered freighter MS Oliva ran aground on Nightingale Island, spilling tons of heavy crude into the ocean. The crew was rescued, but the ship broke up, leaving an oil slick that surrounded the island, threatening its population of rockhopper penguins.^[9][10] Nightingale Island has no fresh water, so the penguins are being transported to Tristan da Cunha for cleaning.^[11]

In culture

Cody Maverick, a seventeen-year-old Northern Rockhopper Penguin, portrayed in the 2007 film Surf's Up.^{[citation needed]}

Secret Agent Buck Rockgut, a Northern Rockhopper Penguin, appeared in three episodes of The Penguins of Madagascar.^{[citation needed]}

In the Happy Feet and Happy Feet Two films, the Barry White-like love guru, Lovelace, is a Rockhopper Penguin, who will instil his wisdom for the price of rocks. Lovelace is voiced by Robin Williams.^{[citation needed]}

Of the Penguin Palooza mascots for the Newport Aquarium, in Kentucky, USA, Rocky is a Northern Rockhopper Penguin.^{[citation needed]}

References