Justification of Red List Category
This species has been classified as Endangered owing to very rapid population decreases over the last three generations (30 years) throughout its range. Precise reasons for the declines are poorly known, but changes in sea surface temperature, pollution, unsustainable levels of harvesting, incidental capture in fisheries and introduced predators are all likely to be implicated.
The global population is estimated at around 240,300 breeding pairs (Cuthbert 2013, TdC and RSPB unpubl. data), with the majority of breeding pairs being found on Gough Island and islands in the Tristan da Cunha group (68,000 pairs on Middle Island in 2015, 64,700 pairs on Gough Island in 2006, 16,000 pairs on Nightingale Island in 2015, 54,000 pairs on Inaccessible Island in 2009 and 3600 pairs on Tristan da Cunha islands in 2015; Cuthbert 2013, RSPB and TdC unpubl. data). The population at Amsterdam Island and St. Paul Island in the Indian Ocean were estimated at 25,000 pairs and 9,000 pairs, respectively, in 1993.
Population trends are poorly known due to the remoteness of the breeding islands. Numbers indicate that populations are still declining (TdC and RSPB unpubl. data). At the species's two breeding locations in the Indian Ocean, Amsterdam and St. Paul, numbers have been declining at an average rate of 3-4% since the early 1970s (CEBC-CNRS unpubl. data). Overall, recent population models indicate that over the past 27 years (three generations), the numbers of Northern Rockhopper Penguins have declined by 57% (Birdlife International 2010). At Amsterdam Island, the decline over the past three generations reaches 74% (CEBC-CNRS unpubl. data).
The Northern Rockhopper Penguin is found in the temperate South Atlantic and Indian oceans, breeding on seven islands between 37–40° S. Approximately 85% of the global population is found in the Atlantic Ocean, breeding at the Tristan da Cunha archipelago and Gough Island (Saint Helena, Ascension and Tristan da Cunha UK Overseas Territories). The remaining 15% of the population is found in the Indian Ocean on Amsterdam and St Paul islands (French Southern Territories) (Cuthbert 2013). The location of these islands places the breeding distribution of most Northern Rockhopper Penguins north of the Sub-Tropical Convergence Zone, with the exception of Gough Island, which lies just south to this frontal system. After breeding and moulting, birds depart on their winter migration and spent up to six months at sea before returning to their respective breeding sites in the following season (Cuthbert 2013). The foraging ranges of Northern Rockhopper Penguins have been investigated for penguins breeding on Nightingale and Gough islands in the Atlantic Ocean (Steinfurth et al. unpubl. data) and for penguins breeding on Amsterdam Island (Bost unpubl. data). During the incubation period, penguins forage more than 800 km and 670 km away from their breeding site on Nightingale and Gough Island, respectively, whereas during brooding foraging ranges are restricted to a maximum distance of 35 km (Nightingale Island) and 24 km (Gough Island) (Steinfurth et al. unpubl. data). Tracking data from Nightingale and Gough islands further reveal that birds disperse after moult over an area stretching to the east along the Walvis Ridge and to the region of the Southern African shelf (approx. 21°S and 15°E) towards the South American continent (approx. 42°W) and south into the region of the Antarctic convergence (approx. 51°S). While penguins breeding on Nightingale Island display high variability in foraging locations during incubation and over-winter migration, penguins breeding on Gough Island show strong directionality with high continuity, travelling south and south-east. Penguins breeding on Amsterdam Island perform looping trips during the incubation, with a mean foraging range of 230 km, but some breeders may forage as far as 410 km off their colony. Brooding birds usually forage much closer to the colony, staying within the region of the shelf (range 8-80 km) (Bost unpubl. data). After moulting, penguins from Amsterdam Island perform long-range movements of up to 2200 km away from the colony, mainly in longitudinal direction without any return to land. The majority of birds head south-east, along the Indian Ridge and forage south of the southern boundary of the subtropical front, using deep waters (3000-3500 m) with very heterogeneous sea surface temperature anomalies and chlorophyll concentrations (Thiebot et al. 2012).
Vagrants have been recorded from South Africa (Rollinson et al. 2013) and the Falkland Islands (Matias et al. 2009, Crofts and Robson 2015). The first breeding attempt of a Northern with a Southern Rockhopper Penguin, Eudyptes chrysocome, was recorded in 2014 on East Falkland (Crofts and Robson 2015).
Adults arrive at the breeding colonies in late July and August. At the Atlantic breeding sites, nests are located in a variety of habitats ranging from open boulder-strewn beaches on Gough Island and Tristan da Cunha to among stands of tussock grass (mainly Spartina arundinacea) on Nightingale, Alex (Middle) and Inaccessible islands (Cuthbert 2013).
In the Indian Ocean, on Amsterdam and St Paul islands, penguins breed in steep or gently sloping ground in a variety of habitats from sea-level up to 170 m above sea-level. Habitats vary from open boulder-strewn beaches to among stands of tussock grass (Spartina arunddinacea and Poa novarae).
Northern Rockhopper Penguins are opportunistic foragers, feeding in different areas during the breeding and non-breeding season. They mainly feed on crustaceans, in particular euphausiids. Other prey items include, fish and cephalopods (Booth and McQuaid 2013, Cuthbert 2013). Juvenile squid co-occurred with crustaceans as the main prey by mass at Amsterdam Island (Tremblay and Cherel 2003). Dietary studies from Tristan da Cunha and Amsterdam Island show seasonal changes in diet with crustaceans and cephalopods, respectively, dominating the diet during the early chick-crèche stage, while fish being the main prey item in the later stages of chick rearing (Tremblay et al. 1997, Booth and McQuaid 2013).
Historically, vast numbers of birds and products from penguins were collected (i.e. eggs were harvested, oil extracted from moulting birds, feathers collected for stuffing pillows and mattresses, and feathers being used for making ornamental table mats on Tristan). These practices were largely discontinued by 1955 (Hagen 1952, Wace and Holdgate 1976, Richardson 1984); the egg harvest was suspended in 2011 (following the Oliva oil spill), but is believed to have resumed. A planned assessment of sustainable harvest levels has been delayed (Bond et al. 2017), but the impact is not currently believed to be significant. Penguins have also been taken as bait for use in crab pots at a number of sites, including at St Paul (Indian Ocean) and Tristan da Cunha (Atlantic Ocean) (Guinard et al. 1998, Cuthbert et al. 2009), and driftnet fishing and rock-lobster fisheries may have caused significant mortality in the past (Ryan and Cooper 1991, Crawford et al. 2017). With only few records of fisheries-related mortality (Ryan and Cooper 1991) and no legal gillnet fishery, bycatch does not appear to be a major threat to the species. However, recent evidence of illegal use of gillnets within the species's foraging range indicates that unobserved bycatch may be higher than suspected (Crawford et al. 2017). Still, it is considered unlikely to affect more than a minority of the overall population (Cuthbert et al. 2009, Cuthbert 2013, Crawford et al. 2017).
In March 2011, MV Oliva ran aground on Nightingale Island and the resultant oil spill reached Inaccessible Island and Tristan da Cunha more than 30 km away (http.www.tristandc.com). Given that the islands are the stronghold for the Northern Rockhopper Penguin, changes in these populations have a substantial impact on the global status of the species. While numbers appeared not to be greatly impacted by the oil spill in 2011, the ongoing threat of reduced reproductive condition suggests this is potentially driving some of the observed declines in the species. The long-term effects of the oil spill on the populations are still unknown. The increasing number of ships passing close to the archipelago each year creates a growing risk of chronic oil pollution as well as risking further catastrophic spills.
Food availability may have been compromised by fisheries, climate change (through increased sea surface temperature [SST]), an increase in eared seal populations and shifts in marine food webs (Cunningham and Moors 1994, Guinard et al. 1998, Barlow et al. 2002, Hilton et al. 2006, Cuthbert 2013). Population declines have occurred over relatively large spatio-temporal scales, possibly implying that at ecosystem-scale, at-sea factors are likely to be involved (Hilton et al. 2006). Breeding success has been found to correlate with SST on Amsterdam Island, while Hilton et al. (2006) found some evidence for a link between decreased primary productivity and population declines and a shift to lower trophic levels due to warming SST. However, different sites showed divergent trends, and the impacts of climate change remain inconclusive.
The only reported cases of major predation by invasive species are the past impacts of feral pigs on Tristan and Inaccessible Island (where pigs were eradicated in 1873 and 1930, respectively). Domestic and feral dogs were also reported to be a problem on Tristan da Cunha (BirdLife International 2010). Although introduced House Mice Mus musculus and House Rats Rattus rattus can be found at some breeding sites, the potential impact is still unknown, but thought to be negligible.
On Amsterdam Island, the species is exposed to avian cholera Pasteurella multocida, but the impact remains unknown (and are currently being investigated). With the population declining more rapidly here than elsewhere, it is suspected that the disease may be a notable impact and likely to be driving additional rates of decline.
In 2014, for the first time a breeding attempt between a Northern and a Southern Rockhopper Penguin was recorded on the Falklands Islands. A hybrid chick hatched, but died before fledging. The impact of hybridization on the population is unlikely to be significant.
Conservation Actions Underway
In response to the ever-increasing vulnerability of the fauna and flora, the Tristan community has taken active steps to conserve their islands. Designed to protect the islands’ natural diversity, the Tristan da Cunha Conservation Ordinance of 1976 proclaimed Gough Island and its territorial waters a Wildlife Reserve. The ordinance was further amended in 1997, when Inaccessible Island and its encompassing waters were declared a Nature Reserve. Today, together they form one of only two Natural World Heritage Sites in the UK Overseas Territories. Finally, a Biodiversity Action Plan was adopted and implemented by the Agriculture and Natural Resources Department, which, for the first time on the island, has appointed a Conservation Officer. With the establishment of a Conservation Department including four full-time staff members and the support of RSPB, JNCC, RSSZS and UK Department for International Development, a constant and consistent long-term monitoring of Tristan da Cunha’s key bird populations is possible. Historic exploitation of penguins, losses due to their use as rock lobster fishing bait and mortality from entanglement in drift nets have ceased and been banned, and breeding colonies are protected as nature reserves at all sites in the Tristan group and Gough Island following the Conservation of native Organisms and Natural Habitats (Tristan da Cunha) Ordinance (2006). Regular surveys carried out by the Tristan Conservation Department at Tristan, and more recently at other islands in the group, provide an important and valuable tool to estimate population size and trends. A conservation action on Nightingale Island has recently included erecting a fence to prevent fur seals from encroaching on one of the penguins’ main breeding sites and covering a deep rock crevice that was trapping and killing breeding birds (Cuthbert 2013).
Immediately after the MV Oliva oil spill, as a precautionary measure, the Tristan da Cunha Conservation Department suspended penguin egg collecting. Furthermore, several ecological and demographic studies have been launched in an effort to help understand the potential impact of any natural and/or anthropogenic threats to this population (e.g. Johaadien 2013, Steinfurth et al. unpubl. data). Survival rates are an important driver of population trends; a long-term demographic study was implemented on Nightingale Island in 2016 to understand the causes of current decline.
An International Species Action Plan and a series of Regional Action Plans were developed in 2008 (BirdLife International 2010) to identify the most important threats to this species and recommend conservation actions, which were updated in 2017.
Amsterdam and Saint Paul islands are included in the National Nature Reserve of the French Southern and Antarctic Territories (TAAF) created in 2006, comprising the entire surface of these islands as well Crozet, Kerguelen, and a large portion of their surrounding waters. French Southern and Antarctic Territories carry out active environmental policies that are especially linked to the conversation of their biodiversity.
Conservation Actions Proposed
A significant population decrease in recent decades has raised serious concern. To help detect and predict population dynamics there is growing need for baseline data and long-term monitoring datasets play an essential role in the decision-making and sustainable management of species. Continuous demographic long-term monitoring programmes therefore should be considered in the design of future surveys that will further help to assess, understand and reduce any potential impact of natural and/or anthropogenic threats to this population. These include mortality from predators (such as Southern Giant Petrel Macronectes giganteus and Brown Skua Catharacta antarctica lonnbergi) and invasives (such as House Mouse Mus musculus and House Rat Rattus rattus), as well as anthropogenic impacts, such as egg harvesting on Nightingale. The impact of disease on this species requires investigation. Local capacity and educate residents and tourists need to be built in order to reduce disturbance. Management plans for the islands where this species occurs should be designed and implemented, and the protection of breeding sites increased. Further Marine IBAs should be designated and implemented.
Identification Approximately 55 cm in length; red eyes; white underparts and slate-gray upperparts; a straight, bright yellow eyebrow ending in long yellow plumes behind the eye; the top of the head has spiked black feathers. Similar species The Southern Rockhopper Penguin differs in having a wider supercilium and longer plumes.
Text account compilers
Pearmain, L., Pütz, K., Shutes, S., Stattersfield, A., Steinfurth, A., Ekstrom, J., Benstead, P., Mahood, S., Martin, R., McClellan, R., Allinson, T, Moreno, R., Calvert, R.
Steinfurth, A., Bost, C., Hilton, G., Bond, A., Garcia Borboroglu , P., Cuthbert, R., Barbraud, C.
BirdLife International (2020) Species factsheet: Eudyptes moseleyi. Downloaded from http://www.birdlife.org on 08/07/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 08/07/2020.