The western rockhopper penguin (Eudyptes chrysocome) is a species of rockhopper penguin. It occurs in subantarctic waters around the southern coast of South America and nearby islands.

The western rockhopper penguin was formerly considered to be conspecific with the eastern rockhopper penguin (Eudyptes filholi) of the western Pacific and Indian Oceans, with the combined species then known as southern rockhopper penguin. These two taxa together had previously also been considered conspecific with the northern rockhopper penguin (E. moseleyi).

Taxonomy

left|thumb|Adult in the [[New Island (Falkland Islands) rookery]]

thumb|right|Eudyptes chrysocome colony on [[Saunders Island, Falkland Islands]]

In 1743 the English naturalist George Edwards included an illustration and a description of the western rockhopper penguin in the first volume of his A Natural History of Uncommon Birds. Edwards based his hand-coloured etching on a preserved specimen owned by Peter Collinson. When in 1758 the Swedish naturalist Carl Linnaeus updated his Systema Naturae for the tenth edition, he placed the western rockhopper penguin with the red-billed tropicbird in the genus Phaethon. Linnaeus included a brief description, coined the binomial name Phaethon demersus and cited Edwards' work. The use of Linnaeus' binomial name was not adopted by later ornithologists, because he had already used the specific demersa for the African penguin which he placed with the wandering albatross in the genus Diomedea.

The western rockhopper penguin was formally described in 1781 by the German naturalist Johann Reinhold Forster under the binomial name Aptenodytes chrysocome. The species is now placed in the genus Eudyptes that was introduced by the French ornithologist Louis Pierre Vieillot in 1816. The genus name combines the Ancient Greek meaning "fine" with meaning "diver". The specific epithet chrysocome is from the Ancient Greek meaning "golden-haired" (from meaning "gold" and meaning "hair").

The species is monotypic; no subspecies are recognised. The northern rockhopper penguin lives in a different water mass from the western and eastern rockhopper penguins, separated by the Subtropical Front, and differs genetically from them. Therefore, northern birds are also now separated, as E. moseleyi. The rockhopper penguins are closely related to the macaroni penguin (E. chrysolophus) and the royal penguin (E. schlegeli).

Interbreeding with the macaroni penguin has been reported at Heard and Marion Islands, with three hybrids recorded there by a 1987–88 Australian National Antarctic Research Expedition.

Description

thumb|left|Western rockhopper penguin (Eudyptes chrysocome) displaying its distinctive crest

This is the smallest of the yellow-crested, black-and-white penguins in the genus Eudyptes. It reaches a length of and typically weighs , although there are records of exceptionally large rockhoppers weighing . It has slate-grey upper parts and has straight, bright yellow eyebrows ending in long yellowish plumes projecting sideways behind a red eye. Outside the breeding season, western rockhopper penguins can be found roaming the waters offshore from their colonies.

These penguins feed on krill, squid, octopus, lantern fish, mollusks, plankton, cuttlefish, and mainly crustaceans.

A rockhopper penguin named 'Rocky' in Bergen Aquarium in Norway lived to 29 years 4 months. It died in October 2003. This stands as the age record for rockhopper penguins, and possibly it was the oldest penguin known.

Behaviour

thumb|left|E. chrysocome on [[Saunders Island, Falkland Islands hopping over a crack]]

Their common name refers to the fact that, unlike many other penguins, which get around obstacles by sliding on their bellies or by awkward climbing using their flipper-like wings as aid, rockhoppers will try to jump over boulders and across cracks. Rockhopper penguins employ different strategies according to their conditions. When making foraging trips, rockhoppers typically leave and return to their colonies in groups. One study showed they are known for going up to away from their colonies when foraging. Females typically forage during the day in 11–12 hour trips consisting of many dives, but they will occasionally forage at night.

thumb|Rockhopper penguin skeleton in [[Manchester Museum]]

Rockhopper penguins employ different strategies and foraging behaviour depending on the climate and environment. A main factor is food location. Subantarctic penguins must dive for longer periods of time and much deeper in search of food than do species in warmer waters where food is more easily accessible. at an average speed of range of .

This decline has earned them the classification of a vulnerable species by the IUCN. Threats to their population include commercial fishing and oil spills.

With the approval of the European Association of Zoos and Aquaria (EAZA), Drusillas Park in East Sussex holds the studbook for rockhopper penguins in Europe. Zoo manager Sue Woodgate has specialist knowledge of the species, so the zoo is responsible for co-ordinating the movements of penguins among zoos in Europe to take part in breeding programmes and offer their advice and information about the species.

Relationship with humans

The indigenous Yahgan people whose territory in Tierra del Fuego overlaps with its distribution often hunted them by slingshot or dart as a source of food.

Rockhopper penguins are the most familiar of the crested penguins to the general public in the present day. Their breeding colonies, namely those around South America, today attract many tourists who enjoy watching the birds' antics. Historically, the same islands had been popular stopover and replenishing sites for whalers and other seafarers since at least the early 18th century. Almost all crested penguins depicted in movies, books and other media are ultimately based on Eudyptes chrysocome.

References

  • ARKive – images and movies of the rockhopper penguin, Eudyptes chrysocome
  • 70South: Info on rockhopper penguins
  • Rockhopper penguins from the International Penguin Conservation website