Northern rockhopper penguin | |
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At Berlin Zoological Garden, Germany | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Sphenisciformes |
Family: | Spheniscidae |
Genus: | Eudyptes |
Species: | E. moseleyi |
Binomial name | |
Eudyptes moseleyi | |
Distribution map of northern rockhopper penguin in yellow |
The northern rockhopper penguin, Moseley's rockhopper penguin, or Moseley's penguin (Eudyptes moseleyi) is a penguin species native to the southern Indian and Atlantic Oceans. It is described as distinct from the southern rockhopper penguin.
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.
The rockhopper penguins have been considered to consist of two species, northern and southern rockhopper penguin, since 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.
More than 99% of northern rockhoppers breed during late spring or early summer on Tristan da Cunha and Gough Island in the south Atlantic Ocean. [6] Breeding colonies are also found on the French Southern and Antarctic Lands of Amsterdam Island and St Paul Island. [7]
It is very rare for the bird to make landfall on the Australian continent, but in 2006, a northern rockhopper was sighted at Robe, South Australia, and in July 2023 a very underweight northern rockhopper was found at Goolwa beach in South Australia. [8]
The rockhopper penguin (Eudyptes chrysocome) was split into three distinct subspecies in 1992; the southern, (E. c. chrysocome), eastern (E. c. filholi) and northern rockhopper penguin (E. c. moseleyi). The three subspecies are distinguished by differences in the length of the tassels of the crests, the size and colour of the fleshy margin of the gape, colour pattern on the underside of the flipper and differences in the size of the superciliary stripe in front of the eye. Additionally, the northern rockhopper penguin is larger than the other two subspecies. [9] Proof that the three subspecies were truly different, in terms of more than reproductive isolation and some morphological features, was found in the mitochondrial sequences of the three species. It was found E. c. filholi and E. c. chrysocome were not as different genetically as E. c. moseleyi was to the other two subspecies. The level of genetic differentiation was similar to the genetic difference found in other penguin subspecies groups. [3]
Another way that scientists were able to differentiate the different subspecies of rockhoppers were in the parasites that fed off each separate rockhopper penguin species. Penguins are parasitised by 15 species of chewing lice in two genera, Austrogoniodes and the monotypic Nesiotinus. Within rockhopper penguins, the host-specific louse Austrogoniodes keleri is present only on southern rockhoppers; the multi-host Austrogoniodes concii parasitises only northern rockhoppers and Austrogoniodes hamiltoni parasitises only eastern rockhoppers. [10] [11] Cross contamination of the lice is not possible naturally due to the fact that chewing lice have limited mobility and heavily rely on their host for survival, meaning that the lice can only be transmitted across species by way of close physical contact. [12]
The northern rockhopper penguin feeds on krill and other sea life such as crustaceans, squid, octopus and fish. [6]
It breeds in colonies in a range of locations from sea level or on cliff sides, to sometimes inland. [6] The Northern form, found in Amsterdam and Gough island, is reproductively isolated from the Crozet and Kerguelen islands. They are monophyletic; meaning they have a split in the mitochondria DNA trees which forms two subspecies: the northern and southern rockhopper penguin. [13] Another interesting difference between the two subspecies is their mating ritual. They both use different songs and head ornaments in their mating signals. The reproductive isolation has led to not only physical difference but also behavioral. [14] The adults feed their chicks lower trophic level prey than they themselves consume. During breeding season the adults eat zooplankton and then transition to fish, showing they favor future reproduction. [15]
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 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. [16]
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. [17] Other possible factors in the decline include disturbance and pollution from ecotourism and fishing, egg-harvesting, and predation and competition from subantarctic fur seals (Arctophoca tropicalis). [6] Surveys show that the birds are at risk of infection by goose barnacles. [18] House mice (Mus musculus) have been introduced into their environment by human sea expeditions. The mice have proven to be invasive, and consume northern rockhopper eggs, as well as hunt their young. In order to preserve the birds, a culling of the mice is being considered. [19] The climate change conditions alter food availability since it reduces nutrients and productivity. This causes an effect on the body mass, causing a negative impact on their reproductivity success. [20]
The northern rockhopper penguin is classified as endangered because of the decline in numbers over the last three generations (or 30 years). [6]
Population Trends by Year and Island [2]
Island | Year | Estimate |
---|---|---|
Gough | 1889 | "millions" |
1956 | ~2 million | |
1979 | 78,300 | |
1984 | 142,800 | |
2004 | 32,400 | |
2006 | 64,700 | |
Tristan | 1824 | >200,000 |
1873 | >200,000 | |
1923 | >12,600 | |
1955 | 5,000 | |
1973 | 7,000 | |
1984 | 4,300 | |
1992 | 3,343 | |
2005 | 3,421 | |
Inaccessible | 1955 | >25,000 |
1989 | 22,000 | |
1999 | 27,000 | |
2004 | 18,000 | |
Nightingale | 1973 | 25,000 |
2005 | 19,500 | |
Middle | 1973 | 100,000 |
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. [21] [22] Nightingale Island has no fresh water, so the penguins were transported to Tristan da Cunha for cleaning. [23]
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 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 on its forehead. 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".
The Fiordland penguin, also known as the Fiordlandcrested penguin, is a crested penguin species endemic to New Zealand. It currently breeds along the south-western coasts of New Zealand's South Island as well as on Stewart Island/Rakiura and its outlying islands. Because it originally ranged beyond Fiordland, it is sometimes referred to as the New Zealand crested penguin. It is occasionally found in Australia.
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 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.
The Antarctic fur seal is one of eight seals in the genus Arctocephalus, and one of nine fur seals in the subfamily Arctocephalinae. Despite what its name suggests, the Antarctic fur seal is mostly distributed in Subantarctic islands and its scientific name is thought to have come from the German vessel SMS Gazelle, which was the first to collect specimens of this species from Kerguelen Islands.
The subantarctic fur seal is a species of arctocephaline found in the southern parts of the Indian, Pacific, and Atlantic Oceans. It was first described by Gray in 1872 from a specimen recovered in northern Australia—hence the inappropriate specific name tropicalis.
Flightless birds have, through evolution, lost the ability to fly. There are over 60 extant species, including the well-known ratites and penguins. The smallest flightless bird is the Inaccessible Island rail. The largest flightless bird, which is also the largest living bird in general, is the common ostrich.
Saint Helena, Ascension Island and Tristan da Cunha, as well the other uninhabited islands nearby, are a haven for wildlife in the middle of the Atlantic Ocean. The islands are or were home to much endemic flora and fauna, especially invertebrates, and many endemic fish species are found in the reef ecosystems off the islands. The islands have been identified by BirdLife International as Important Bird Areas for both their endemic landbirds and breeding seabirds.
The Chatham penguin, also known as the Chatham crested penguin, Chatham Islands penguin, or Warham's penguin, is an extinct species of crested penguin previously endemic to the Chatham Islands of New Zealand. It is known only from subfossil bones and probably became extinct within 150–200 years after Polynesians arrived in the Chatham Islands around 1500 CE.
The Southern Indian Ocean Islands tundra is a tundra ecoregion that includes several subantarctic islands in the southern Indian Ocean.
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.
The Tristan da Cunha–Gough Islands shrub and grasslands is a terrestrial ecoregion which covers the Tristan da Cunha archipelago and Gough Island in the South Atlantic Ocean. The islands' remote location gave rise to many endemic species.