VU
Southern Rockhopper Penguin Eudyptes chrysocome



Justification

Justification of Red List Category
Southern Rockhopper Penguin populations have declined rapidly from huge abundance in the first half of the 20th century, at a rate exceeding 30% over the past three generations. While some colonies appear to have stabilised, mass-mortality events believed to be connected to water temperature mediated food availability are occurring too frequently for populations to recover, and as such the population is suspected to continue to decline at a rapid rate. As such, the species has been assessed as Vulnerable.

Population justification
Latest counts on islands off South America revealed a total of ca. 850,000 breeding pairs of subspecies E.c. chrysocome (Falkland Islands: 319,163 breeding pairs in 2010, Isla de los Estados: 135,000 pairs in 2010, Isla Pinguino: 1,061 pairs in 2014, Isla Ildefonso: 86,400 pairs in 2006, Diego Ramirez: 132,721 pairs in 2002, Isla Noir: 158,200 pairs in 2005, Isla Barnevelt: 10,800 pairs in 1992, Cape Horn: 600 pairs in 1992, Isla Terhalten: 3,000 pairs in 2008 and Isla Buenaventura: 500 pairs in 1992 [Schiavini et al. 2005, BirdLife International 2010, Raya Rey et al. 2014, Gandini et al. 2017, Baylis et al. 2013]). 

The subspecies E. c. filholi totals 422,000 breeding pairs; Prince Edward Islands: 38,000 pairs in 2008/09 (Crawford et al. 2009); Marion Island: 58,955 pairs in 2018/19 (Makhado et al. unpubl.); Crozet Islands: 152,800 pairs in 1982; Kerguelen Islands (French Southern Territories): 85,500 pairs in 1985; Heard Island (Heard and McDonald Islands [to Australia]): 10,000 pairs in 2003; Macquarie Island (Australia): 37,500 pairs in 2007; Campbell (New Zealand): 33,239 pairs in 2012 (Morrison et al. 2015); Auckland (New Zealand): 3,000 pairs in 1990 and Antipodes Islands (New Zealand): 2,700-3,600 pairs in 1990.

There is evidence that there are at least three subpopulations, two within E. c. chrysocome (Lois et al. 2020) and E. c. filholi separate from these (Mays et al. 2019). Mays et al. (2019) found the best-supported population models for the southern rockhoppers combined E. c. chrysocome and E. c. filholi into a single lineage or 2 lineages with bidirectional gene flow, and thus proposed that they should be treated as different management units. Lois et al. (2020) added new information on the southern rockhopper (E. c. chrysocome) from the southwest Atlantic Ocean. Studying the genetic structure of individuals from different colonies located in the southwest Atlantic they found evidence for two genetic clusters, one northern (Falkland/ Malvinas Islands and Isla Pingüino) and one southern (Terhalten and Staten Island).

Trend justification
Several populations have experienced major long-term population crashes. Approximately 1.5 million pairs are estimated to have been lost from Campbell Island (94 % of the original total) between 1942 and 1986 (Cunningham and Moors 1994), with a further 21.8 % decrease between 1986 and 2012 (Morrison et al. 2015). In the Falkland Islands (Malvinas), the population fell by around 1.2 million pairs between 1932 and 2000 (20 % of the original total) (Pütz et al. 2003). At Staten Island, the numbers of Southern Rockhopper Penguins decreased by 24% between the censuses of 1998 and 2010 (Raya Rey et al. 2014). Numbers at Marion Island decreased by about 65 %, from 173,077 pairs in 1994/95 to 58,955 pairs in 2018/19 (Dyer and Crawford 2015, Makhado et al. unpubl.). The long-term trends remain unknown for the Kerguelen and Crozet populations (CEBC-CNRS database, C.A. Bost pers. comm.). Several other populations at the Auckland Islands and Antipodes Islands appear to have suffered severe declines of more than 40 % between the 1970s and the 1990s (Cooper 1992, Hiscock and Chilvers 2014).
 
Population modelling, based on those breeding sites that have been accurately surveyed, indicates that between 1971 and 2007 (three generations) the number of Southern Rockhopper Penguins declined by 34 % (BirdLife International 2010). In early 2016, there was a mortality of unknown extent of Southern Rockhopper Penguins in the Southwest Atlantic before and during the moulting period, with dead penguins (mainly caused by starvation) found along the coasts of Tierra del Fuego (around 300), the Falkland (Malvinas) Islands (300-400 on Saunders Islands) and near Puerto Deseado (around 200) (A. Raya Rey and S. Crofts pers. comm.). However, while the extent of this recent mortality has not been established, it appears that it may have affected the population at a larger regional scale (Crofts and Stanworth 2016, 2017, 2019, Morgenthaler et al. 2018.). 

There has been no update to the estimated trend modelled across all published survey data up to 2007 (BirdLife International 2007), which calculated a decline of 34% over the previous three generations. This was largely driven by the declines in the Falklands (Malvinas), where data are most complete, and to a lesser extent, Marion Island (BirdLife International 2010). Subsequently some studies have indicated that declines may have paused across a number of these colonies (Baylis et al. 2013, Morrison et al. 2015), however a mass-mortality event in 2016, mirroring that in 1986 (Boersma 1987) appears to have resulted in an immediate 31% reduction in numbers of breeding pairs in the Falklands (Malvinas) colonies (Crofts and Stanworth 2017), with little or no recovery since (Crofts and Stanworth 2019). It appears that El Niño related mass mortality events may currently be too frequent for the populations to recover. As such the estimated trend over the past three generations remains a rapid decline at a rate in excess of 30%, which is suspected to continue at this rate over the next three generations.

Distribution and population

Eudyptes chrysocome breeds on islands located in the South Atlantic, Indian and Pacific Oceans, ranging from 46º S in the South Atlantic and South Indian Oceans to Macquarie Island at 54ºS in the South Pacific Ocean

After breeding, birds head away from colonies and remain at sea for much of the non-breeding season, travelling up to 5,000 km in this time, although maximum distance to the colony is typically less than 1,000 km during the period birds were tracked (Pütz et al. 2002, 2006). Birds disperse widely, including south to the South Sandwich Islands, Antarctica (Pütz et al. 2006). 

Ecology

This species returns to its breeding colonies in October, which range from sea-level sites to cliff-tops, and sometimes inland. Clutch size is two eggs, laid and incubated during November and December for 32-34 days. Chicks fledge and depart the colony in February (BirdLife International 2010). At most breeding sites, only one chick fledges, but there is some evidence that it is not unusual for Southern Rockhopper Penguins in the Falkland Islands (Malvinas) to raise two chicks (Clausen and Pütz 2002, Poisbleau et al. 2008). Pairs successfully fledging two chicks has also been observed on Crozet (C. A. Bost pers. comm.).

Southern Rockhopper Penguins prey on a variety of fish, crustaceans and cephalopods, with components varying in importance spatially and temporally (Williams 1995, Pütz et al. 2013). There is also individual dietary specialization during part of their annual cycle (Dehnhard et al. 2016).

At the Falklands (Malvinas), hybridization occurs with Macaroni (White and Clausen 2002) and Northern Rockhopper Penguins (Crofts and Robson 2016). 

Threats

Climate change appears to be a significant factor in driving declines. Survival of adult Southern Rockhopper Penguins appears to be sensitive to ocean temperatures, with highest survival probabilities under moderately-cold to long-term average temperature, and reduced survival probabilities under increasingly cold or warm ocean temperatures (Raya Rey et al. 2007, Dehnhard et al. 2013a). Southern Rockhopper Penguins in the Falklands (Malvinas) delayed breeding under warmer environmental conditions and laid lighter eggs, with potential impacts on breeding success (Dehnhard et al. 2015a, b). Temperature extremes have caused collapse in accessible food resources in the past, and these are part of an ongoing trend in more frequent unusual oceanographic conditions recurring in the area (Dehnhard et al. 2013a). Penguins and their habitats may also be threatened by increased frequency of storm events at breeding sites (Wolfaardt et al. 2012). Severe mortality was recorded in moulting birds found unusually far from colonies in 2016, which appeared to be related to a set of poorly understood oceanographic conditions, leading to lowered primary productivity near to breeding sites immediately prior to moult (Morgenthaler et al. 2018). Wind-patterns are also subject to change under global warming scenarios and have been shown to affect the foraging success of rockhopper penguins; the currently dominating southerly and westerly winds increased foraging success while foraging success was lower under northerly and easterly wind directions, which may become more frequent in the future (Dehnhard et al. 2013b).

Besides these apparent bottom-up effects, climate change may also lead to top-down changes in food web structure, causing increased inter-specific competition and secondary predation, e.g. competition and predation by the rapidly increasing pinniped (fur seal and sea lion) populations (Barlow et al. 2002, Raya Rey et al. 2012, Morrison et al. 2017). Overwintering conditions are thought to influence the proportions of birds skipping breeding at Marion Island (Crawford et al. 2006) and potentially elsewhere. Predation by native eared seal species impacts, for example, the populations on Marion and Campbell Islands, where modelling indicates that it is an important driver of the very rapid declines in the local population. Yet, the impacts of occasional years of poor food availability appear to exert a larger impact on the species' demographic rates than do predation regimes (Morrison et al. 2017). Overwintering conditions are thought to influence the proportions of birds skipping breeding at Marion Island (Crawford et al. 2006) and potentially elsewhere. The number of Southern Rockhopper Penguins returning to Marion Island to breed decreased by about 20% between 1994/95 and 2007/08 and was significantly correlated with breeding success (Crawford et al. 2008).

The number of Southern Rockhopper Penguins affected by oil pollution is currently not thought to be as great as in the past, when 40,000 Magellanic Penguins Spheniscus magellanicus were estimated to be contaminated annually in Argentina (Gandini et al. 1994). In Patagonian coastal waters, hydrocarbon exploitation still poses a threat (Ellis et al. 1998), as does the potential development of hydrocarbons at the Falkland Islands (Malvinas) (between 2008 and 2019, fewer than a hundred oiled individuals were reported in the Falklands (Malvinas), with the highest occurrence in September and October; S. Crofts pers. comm.). Rockhopper penguins on Staten Island have elevated mercury levels, despite foraging at a lower trophic level when compared to conspecifics from other breeding sites (Brasso et al. 2015).

At some sites, introduced grazing animals have caused significant vegetation loss. In the past, overgrazing by rabbits led to serious erosion and landslips on Macquarie Island; however, vegetation is now recovering following the successful Macquarie Island Pest Eradication Project (Parks and Wildlife Service 2014). The impact of grazing goats and deer at Isla de los Estados is not known and should be investigated. It is thought that introduced pigs on the Auckland Islands continue to negatively impact local penguin populations, and eradication efforts have been suggested (BirdLife International 2010). Cats and rats are present in parts of the species’ range, but have not been found to cause significant mortality (BirdLife International 2010).

There are very few records of disease outbreaks, although a few colonies are visited regularly. Avian cholera caused the deaths of a small number of adults and chicks at Campbell Island in 1985/86 (de Lisle et al. 1990). Avian Pox has been reported within the Falkland (Malvinas) population, but in a small number of individuals at few sites only (e.g. New Island in 2014, P. Quillfeldt unpubl.). An unknown disease caused up to a hundred adult mortalities at Steeple Jason (Crofts 2014). The massive mortality event on the Falklands (Malvinas) in 2002/03 was due to a Harmful Algal Bloom (HAB), causing mortality via paralytic shellfish poisoning (Uhart et al. 2007). Impacts were region-wide, and affected populations took several years to recover (Crofts 2014).  At the Falklands (Malvinas) and in southern Patagonia, adult mortalities of an unknown extent were reported during the moulting period following the breeding season 2015/16 (Crofts and Stanworth 2016, 2017, A. Raya Rey pers. comm.).

Egg collection was common at some colonies until the 1950s, such as in the Falkland Islands (Malvinas), but is now prohibited. Historically, penguins were taken as bait for use in crab pots at a number of sites, including some Chilean islands (Ryan and Cooper 1991, P. G. Ryan in litt. 1999). The disappearance of the colony on Isla Recalada in Chile indicates that human depredation, in this case the collection of zoological specimens and as bait for crab pots (Oehler et al. 2007), is still a serious threat to colonies where sites are accessible and not well protected. Although the number of birds taken in recent years from other Chilean colonies is less than 500 individuals per year (BirdLife International 2010), the potential remains to drive slow declines in parts of the species's range.

Another potential threat stems from interaction with fisheries; levels of bycatch mortality appear to be insignificant, but resource competition and indirect changes to the food web through modification of ecosystems may have more extensive impacts (Crawford et al. 2017). Land-based human threats at breeding sites, such as tourism, research and land management, are considered low, and although it may vary on local scales, disturbance from such activities is currently deemed not significant at an overall population level at the Falklands (Malvinas) (Crofts 2014). Tourism is strictly regulated with visits only to a small percentage of the global population.

Conservation actions

Conservation Actions Underway
Regular monitoring is undertaken on Staten, Falklands (Malvinas), Marion and Campbell Islands (BirdLife International 2010, Raya Rey et al. 2014). Several ecological and demographic studies have been undertaken (Ellis et al. 1998, Guinard et al. 1998, Dehnhard et al. 2013a, 2014). Research has attempted to determine the cause of historic declines using stable isotope analysis of museum skins (Hilton et al. 2006). An International Species Action Plan and a series of Regional Action Plans have been developed (BirdLife International 2010). Following this, research has been conducted at many breeding sites following the recommendations made in the report. A Falkland Island Species Action Plan was completed in 2014 (Crofts 2014). 

Conservation Actions Proposed
Continue or start to monitor all populations, especially in the Indian Ocean, in order to assess trends (Guinard et al. 1998, BirdLife International 2010, Baylis et al. 2013, Raya Rey et al. 2014) and improve methodologies for monitoring. Conduct long-term demographic studies to understand the causes of the current decline (BirdLife International 2010, Dehnhard et al. 2013a, b). Conduct genetic studies to determine the taxonomic status of the species (E. chrysocome vs. E. filholi). Conduct research into spatial and temporal links between population trends, sea-surface temperature and primary productivity (BirdLife International 2010). Investigate the possible impact of oil exploitation (Guinard et al. 1998). Conduct studies to assess interactions with commercial fisheries (Ellis et al. 1998). Assess the threat from introduced predators. Reduce disturbance from ecotourism through the use of codes of conduct. Assess the threats of disease and increase biosecurity measures (Crofts 2014). Bring in international agreements for the creation of further Marine Protected Areas and agreements on the regulation of fisheries, oil and other marine activities. Design and implement management plans for the islands, including appropriate protocols for immediate actions when needed (e.g. mass mortalities). Increase awareness including by involving local communities via school children, with resources and materials for school teachers. In particular increase awareness of the effects of climate change and what the public could do to mediate these effects.

Identification

Identification. 55 cm. Average weight of 3.35 kg. A robust body with white underparts and slate-grey upperparts. Distinctive red eyes and a short reddish brown bill. A straight yellow eyebrow ending in sideways projecting plumes extends above the eye. Similar species. The Southern Rockhopper Penguins differ from their Northern counterparts in having a narrower supercilium and shorter plumes, which reach just over the black throat. Immature birds have only a narrow supercilium and a pale mottled grey chin.

Acknowledgements

Text account compilers
Shutes, S., Stattersfield, A., Martin, R., Pearmain, L., Moreno, R., Pütz, K., Trathan, P. N.

Contributors
Bost, C., Crawford, R., Crofts , S., Dehnhard , N., Gales, R., Garcia Borboroglu , P., Harris, S., Hilton, G., Huin, N., Kirkwood, R., Makhado, A., Moore, P., Morrison , K., Pütz, K., Quillfeldt , P., Raya-Rey, A., Ryan, P.G., Schiavini, A., Whitehead , O. & Wilson, K.-J.


Recommended citation
BirdLife International (2021) Species factsheet: Eudyptes chrysocome. Downloaded from http://www.birdlife.org on 06/03/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 06/03/2021.