The rockhopper penguins are three closely related taxa of crested penguins that have been traditionally treated as a single species and are sometimes split into three species.
Not all experts agree on the classification of these penguins. Some consider all three as distinct species, some split the western and eastern forms into the southern rockhopper penguin and keep the northern rockhopper as distinct, while other experts consider all three potential varieties to be one species.
Appearance
Rockhopper penguins (Eudyptes chrysocome) are among the smaller species of penguin. After reaching full growth, they are about 20 inches or 50 centimetres in height.[1] Males and females cannot be distinguished visually, so a DNA test is conducted by taking a feather from the bird to determine its gender.[2] Like many penguins, rockhopper penguins have a white belly and the rest of their body is black.[2] Some characteristics that differentiate them from the other penguins are their red eyes, orange beak, pink webbed feet, and the yellow and black spiky feathers they have on their head.[1][3] Although their yellow and black spiky feathers differentiate them from other penguins, rockhopper penguin chicks do not have them; these feathers develop with age.[3] Their orange beak is initially black, but as the penguins get older, their beaks turn orange.[3] Due to the harsh rocky environment, they cannot slide on their bellies like most penguins, so they hop to get from one place to another, hence their name.[2]
The yellow and black ‘hair’ they have on the top of their head is similar to that of the Macaroni penguin (Eudyptes chrysolophus).
Subspecies
What separates rockhopper penguins into subspecies is their location of reproduction and reproductive behaviors. The difference in mating signals found between the subspecies E. chrysocome (southern) and E. moseleyi (northern) seems to have occurred quickly, thus these behavioral changes are enough to isolate these taxa.[4]
Southern rockhopper penguins are split into two subspecies and they are defined by their location of reproduction. The subspecies E. c. filholi (eastern) is known to reproduce in the sub-Antarctic around the Prince Edward Islands, Crozet Islands, Kerguelen Islands, Heard Island, Macquarie Island and Campbell, Auckland and Antipodes Islands. The subspecies E. c. chrysocome, which may be referred to the true southern subspecies, reproduces at offshore islands in southern Chile, Argentina and at the Falkland Islands. The Falkland Islands are known to have one of the largest populations of southern rockhopper penguins.[5]
Northern rockhopper penguins breed in cool temperate climates including on the islands of Gough and Tristan da Cunha in the Atlantic Ocean and St. Paul and Manchester in the Indian Ocean. The southern rockhopper breeds on the Falkland Islands, Argentina and Chile, with breeding colonies around Cape Horn in South America, and Gough, Prince Edward, Marion, Crozet, Kerguelen, Heard, Macquarie, Campbell, Auckland and Antipodes Islands in the southern Indian Ocean. Eastern rockhopper penguins are mostly found breeding on Campbell Island in New Zealand, but their numbers have declined immensely. [6] Rockhopper penguins usually make their habitat in rocky shorelines. They make nests and burrows in tall grasses called tussocks.
Diet
The rockhopper penguin's diet consists of krill and small crustaceans, which may include shrimp, crabs, lobsters or crayfish.[2] They also eat squid and myctophid fish.[2][3] Rockhopper penguins consume more krill than they do fish; their diet changes during migration and as the seasons change.[3] Rockhopper penguins can be at sea for several days while hunting. They can dive up to 330 feet (100m) for many minutes at a time while searching for prey.[2]
Reproduction
Rockhopper penguin with chicks, New Island, Falkland Islands
Rockhoppers are the most widespread crested penguins.[7] Their range goes from the Antarctic front to the South Atlantic and Indian Oceans.[7] Because of how widespread they are, breeding varies among the penguins in different areas. Northern Penguins begin the mating process two months earlier than Southern ones.[8] Two eggs are usually laid a few days apart during early November in hope that at least one will survive, and the second egg is usually larger than the first. They will use the same nest as they did in previous years as well. Eggs hatch about a month later and the mother will have food for the chick.[9]
Taxonomy
There are currently 19 species and six genera of living penguins. The rockhopper penguin has 3 subspecies: Eudyptes filholi, the Eastern Rockhopper; Eudyptes mosleyi, the Northern Rockhopper; and the Eudyptes chrysocome, the Southern Rockhopper. They are separated by their locations of breeding. There are four other species in the genus Eudyptes: E. pachyrhynchus, E. robustus, E. chrysolophus, and E. schlegeli.[10] The three subspecies of the rockhopper penguin are believed to have split up because of latitude and watermasses rather than because of geographic distances. Research suggests that during the early Pleistocene, the Southern Ocean was cold and rockhopper populations from the Atlantic and Indian Oceans remained undifferentiated and lived in the same watermass. The mid-Pleistocene climatic transition was associated with the southward migration of frontal positions and islands became surrounded by subtropical water masses, resulting in a split between Northern and Southern rockhopper penguins. Many advance and retreat cycles of Patagonian icecaps during the late Pleistocene may have created a barrier to gene flow between Southern Pacific and Southern Atlantic populations, causing a split between Southern and Eastern rockhopper populations.[11]
Although the rockhopper penguin is one of the world's most numerous penguin populations, it is estimated that the population declined by some 30 percent over the final 30 years of the 20th century.[1] The cause of this decline is mainly unknown, but scientists have speculated that humans are involved, mostly by commercial overfishing, oil exploitation, and pollution.[1] Recent research has shown that rockhopper penguin population declines with changes in ocean surface temperature, indicating a direct impact from climate change.[13] These activities have depleted much of the rockhopper penguin's food supply and raised the sea surface temperatures, and because this species is geographically isolated to the tip of South America and the Falkland Islands and is very sensitive to food web changes, there is little foreseeable opportunity for the penguins to recover.[13][14]
Oil spills
An oil spill followed the grounding of the MS Oliva off Nightingale Island in 2011, which resulted in thousands of Rockhopper penguins becoming oiled. Oil spills have impacted many penguin species since the conversion of shipping from sail and coal propulsion to liquid-based fuels in the early 20th century.
The gentoo penguin is a penguin species in the genus Pygoscelis, most closely related to the Adélie penguin and the chinstrap penguin. The earliest scientific description was made in 1781 by Johann Reinhold Forster with a type locality in the Falkland Islands. The species calls in a variety of ways, but the most frequently heard is a loud trumpeting, which the bird emits with its head thrown back.
The southern rockhopper penguin is a species of rockhopper penguin, that is sometimes considered distinct from the northern rockhopper penguin. It occurs in subantarctic waters of the western Pacific and Indian Oceans, as well as around the southern coasts of South America.
The king penguin is the second largest species of penguin, smaller, but somewhat similar in appearance to the emperor penguin. There are two subspecies, A. p. patagonicus and A. p. halli; patagonicus is found in the South Atlantic and halli in the South Indian Ocean and at Macquarie Island.
The macaroni penguin is a species of penguin found from the Subantarctic to the Antarctic Peninsula. One of six species of crested penguin, it is very closely related to the royal penguin, and some authorities consider the two to be a single species. It bears a distinctive yellow crest that resembles macaroni, from which its name is derived. Its face and upperparts are black and sharply delineated from the white underparts. Adults weigh on average 5.5 kg (12 lb) and are 70 cm (28 in) in length. The male and female are similar in appearance; the male is slightly larger and stronger with a relatively larger bill. Like all penguins, it is flightless, with a streamlined body and wings stiffened and flattened into flippers for a marine lifestyle.
The erect-crested penguin is a penguin endemic to the New Zealand region and only breeds on the Bounty and Antipodes Islands. It has black upper parts, white underparts and a yellow eye stripe and crest. It spends the winter at sea and little is known about its biology and breeding habits. Populations are believed to have declined during the last few decades of the twentieth century, and the International Union for Conservation of Nature has listed it as being "endangered".
Eudyptes is a genus of penguins whose members are collectively called crested penguins. The exact number of species in the genus varies between four and seven depending on the authority, and a Chatham Islands species became extinct in recent centuries. All are black and white penguins with yellow crests, red bills and eyes, and are found on Subantarctic islands in the world's southern oceans. All lay two eggs, but raise only one young per breeding season; the first egg laid is substantially smaller than the second.
The royal penguin is a species of penguin, which can be found only on the sub-Antarctic Macquarie Island and adjacent islands. The International Union for Conservation of Nature (IUCN) classifies the royal penguin as Least Concern. The scientific name commemorates the German zoologist Hermann Schlegel.
The Scotia Sea is a sea located at the northern edge of the Southern Ocean at its boundary with the South Atlantic Ocean. It is bounded on the west by the Drake Passage and on the north, east, and south by the Scotia Arc, an undersea ridge and island arc system supporting various islands. The sea sits atop the Scotia Plate. It is named after the expedition ship Scotia. Many icebergs melt there.
Mendosoma lineatum, the telescope fish, real bastard trumpeter or common trumpeter, is a species of marine ray finned fish belonging to the family Latridae, the trumpeters. It is native to the subantarctic and cooler temperate waters of the Southern Ocean. It inhabits tide pools and surge channels and has been found living inside such invertebrates as salps. It occurs from near the surface to a depth of about 20 metres (66 ft). This species can reach a length of 40 centimetres (16 in) TL. This species was thought to be the only known member of its genus.
The Kerguelen Islands are part of the Southern Indian Ocean Islands tundra ecoregion that includes several subantarctic islands. In this cold climate plant life is mainly limited to grasses, mosses and lichens, although the islands are also known for the indigenous edible Kerguelen cabbage. The islands are at the Antarctic convergence, where cold water moving up from the Antarctic mixes with the warmer water of the Indian Ocean. As a consequence, marine mammals, especially seals, and seabirds and penguins are numerous.
The Southern Indian Ocean Islands tundra is a tundra ecoregion that includes several subantarctic islands in the southern Indian Ocean.
The northern rockhopper penguin, Moseley's rockhopper penguin, or Moseley's penguin is a penguin species native to the southern Indian and Atlantic Oceans. It is described as distinct from the southern rockhopper penguin.
The eastern rockhopper penguin, also known as the tawaki piki toka, is a crested penguin with yellow crest feathers. It is a subspecies of the southern rockhopper penguin found in subantarctic regions and the Indian Ocean. It is one of the smallest crested penguins and has distinctive pink margins around its bill.
↑ Jouventin, P. P., Cuthbert, R. J., & Ottvall, R. R. (2006). Genetic isolation and divergence in sexual traits: evidence for the northern rockhopper penguin Eudyptes moseleyi being a sibling species. Molecular Ecology, 15(11), 3413-3423. doi:10.1111/j.1365-294X.2006.03028.x
↑ Baylis, A., Wolfaardt, A., Crofts, S., Pistorius, P., & Ratcliffe, N. (2013). Increasing trend in the number of Southern Rockhopper Penguins (Eudyptes c. chrysocome) breeding at the Falkland Islands. Polar Biology, 1007-1018.
↑ Rockhopper Penguin: Eudyptes chrysocome. (n.d.). Retrieved October 24, 2014.
1 2 Hull, C., Hindell, M., Mar, K., Scofield, P., Wilson, J., & Lea, M. (n.d.). The breeding biology and factors affecting reproductive success in rockhopper penguins Eudyptes chrysocome at Macquarie Island. Polar Biology, 711-720.
↑ Jouventin, P., Cuthbert, R., & Ottvall, R. (n.d.). Genetic isolation and divergence in sexual traits: Evidence for the northern rockhopper penguin Eudyptes moseleyi being a sibling species. Molecular Ecology, 3413-3423.
↑ Ksepka, D. (2010, January 30). Family Tree of the Living Penguins. Retrieved October 23, 2014.
↑ de Dinechin, M., Ottvall, R., Quillfeldt, P., & Jouventin, P. (2009). Speciation chronology of rockhopper penguins inferred from molecular, geological and palaeoceanographic data. Journal of Biogeography, 36(4), 693-702. doi:10.1111/j.1365-2699.2008.02014.x
1 2 Dehnhard, N., Poisbleau, M., Demongin, L., Ludynia, K., Lecoq, M., Masello, J., & Quillfeldt, P. (2013). Survival of rockhopper penguins in times of global climate change. Aquatic Conservation: Marine and Freshwater Ecosystems, 23(5), 777-789. Retrieved October 23, 2014, from Wiley Online Library.
↑ Hilton, G., Thompson, D., Sagar, P., Cuthbert, R., Cheryl, Y., & Bury, S. (2006). A stable isotopic investigation into the causes of decline in a sub-Antarctic predator, the rockhopper penguin Eudyptes chrysocome. Global Change Biology, 2006(12), 611-625. Retrieved October 23, 2014, from Web of Science.
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