Justification of Red List Category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing (except at the northern limit of the range), and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The global population is estimated at 1.1 million annual breeding pairs (range 1,084,320-1,228,320) (Bost et al. 2013, Weimerskirch et al. 2018).
The King Penguin has two subspecies; A. patagonicus patagonicus and A. patagonicus halli. It breeds on various sub-Antarctic islands, with the latter found at the Kerguelen Islands and Crozet Island (French Southern Territories), Prince Edward Islands (South Africa), Heard Island and McDonald Islands, and Macquarie Island (Australia); the former breeds at South Georgia (Georgias del Sur) with small colonies also present on the Falkland Islands (Islas Malvinas) that are still increasing (del Hoyo et al. 1992) and in southern Chile (Kusch and Marín 2012). Occasionally one or two pairs also appear to attempt breeding at the South Sandwich Islands (Convey et al. 1999) and the South Shetland Islands (Juáres et al. 2017, Gryz et al. 2019).
Counts of king penguins have been made in a consistent manner at peak of laying (breeding pairs) and end of winter (September or October: surviving chicks) on Possession island, Crozet (annually since 1978), Kerguelen (annually since 1986) and Marion island (annually since 1987). The population has begun to stabilize over the past decade, and the global population is estimated at 1.1 million annual breeding pairs (range 1,084,320–1,228,320) (Bost et al. 2013, Weimerskirch et al. 2018).
The most recent evaluations indicate that important populations occur at South Georgia c. 450,000, Crozet Is. 377.040 pairs, Kerguelen Is. 377,000 (Barbraud et al. submitted), Heard Is. 80,000, Macquarie Is. 150,000–170,000, Marion-Prince Edward Is. 90.000 (Dyer and Crawford 2015), Falkland Is. c. 1,000, and Prince Edward Is. 2,000.
Importantly Crozet islands are no longer the main breeding location but only the 3rd largest since the crash at the Hogs Island colony (88% decrease, over the past 35 years Weimerskirch et al. 2018). This population change at the northern limit of the breeding range has been the most important recently reported for this species. South Georgia has become the largest breeding site worldwide (holding 40% of the global population), but population estimates from there require updating for confirmation.
This species has an unique, prolonged, breeding season (14-15 months) among penguins with an asynchronous laying period. Because of the long breeding cycle, colonies are continuously occupied and crèched chicks can be observed throughout the year. Hence, it spends much of its time near breeding areas.
The breeders usually lay an egg every year, even when failure is almost certain. Successful breeding occurs, at best, every two years only (Jiguet and Jouventin 1999). The King Penguin does not build a nest but incubates its egg on the feet. It is highly territorial.
It is an oceanic, long-distance forager (Bost et al. 2009), capturing prey by means of pursuit deep-diving mostly during the day, and foraging at depths of 160-200 m, up to more than 360 m (Bost et al. 2002, Charrassin et al. 2002). The prey comprises mainly myctophid fish but ice fish and cephalopods are also taken. It captures prey by means of pursuit, diving mostly during the day, and forages at depths of 160-200 m.
In the non-breeding season (February-September) adults migrate considerable distances from breeding islands (Orgeret et al. 2019). It arrives at colonies to breed between September and November, forming colonies on flattish beaches free of ice. The annual moult takes place from October until January. The main marine predators of both adults and young are killer whales (Orcinus orca) and leopard seals (Hydrurga leptonyx). Antarctic fur seals (Arctocephalus gazella) and South American sea lions (Otaria flavescens) occasionally prey on this species as well. In the colonies, giant petrels (Macronectes spp.) prey on chicks, and skuas (Stercoraria spp.) and lesser sheathbills (Chionis minor) take eggs and sometimes small chicks (Bost et al. 2013).
Recent studies showed that sea surface temperatures constitute an important driver of the foraging distribution of this species (Péron et al. 2012, Bost et al. 2015). The results of modelling imply that the projected southwards shift of the Antarctic Polar Front (APF) could have negative consequences for King Penguins as, for at least at some colonies in the Southern Indian Ocean, they would have to travel significantly farther to reach their preferred cold water foraging grounds (Péron et al. 2012). IPCC climate models suggest that the APF could shift southward 25-40 km per decade, with the northern colonies likely to be more affected than southern ones. The severity of the threat posed by climate change is still unclear, as it may be responsible for recent observed increases, but equally may drive rapid declines over relatively short periods (Péron et al. 2012, Trucchi et al. 2014, Cristofari et al. 2018). Similarly, other work on the stability of the APF suggest that the deeper layers may be less prone to movement than surface layers, so that the location of the deep front (and its associated nutrient gradients, strong flow and upwelling) may become decoupled in the future (Meijers et al. 2019).
Furthermore, the depth of the mixed layer may deepen as the Southern Ocean warms and positive Southern Annual Mode (SAM) anomalies occur more frequently. Although there is still uncertainty about how the mixed layer may respond to alterations in the atmosphere, changes in SAM could alter the exchange of heat and carbon between ocean and atmosphere (Sallée et al. 2010). This in turn has the potential to drive the main prey of King Penguins to greater depths forcing the penguins to dive deeper (Péron et al. 2012). Insufficient food may decrease survival of adults (Olsson and van der Jeugd 2002).
Disease could become an issue in the future as an unknown disease killed 250–300 King Penguins at Marion Island in late October 1992 (Cooper et al. 2009).
Disturbance from helicopter flights may cause some breeding failure or lead pairs to relocate to alternative breeding sites (Cooper et al. 1994), and a large scale mortality event associated with aerial logistical operations occurred at Macquarie Island in 1990 (Rounsevell and Bins 1991). Other human impacts could potentially include construction of new science facilities and fisheries, particularly fisheries for myctophid fish if they develop (e.g. Moore et al. 1998). Oil spills may also be important at local scales. Potential disturbance from tourists, and scientists are now strictly controlled. Natural predation of chicks by Brown Skua Catharacta antarctica and giant petrels Macronectes spp. has a low level of impact on the species.
Invasive species may have low-level impacts on King Penguins in parts of the range. Feral cats Felis catus may depredate chicks (reduced reproductive success), but has no impact on adult mortality (Bost et al. 2013). However, cats are present only at a minority of sites, and no population declines have been associated with cat predation. Recent observations in Hogs Island (Crozet) where feral cats are present around the King Penguin colony tend to invalidate that cats could be responsible for the decrease of this major colony (Bost and Chaigne, unpubl. data). The Argentine Gray Fox (Chilla) Lycalopex griseus, is native to much of the southern extreme of south America, but was introduced to Tierra del Fuego island in 1951 in an attempt to control rabbits (Jaksic and Yáñez 1983). Foxes are now causing some chick mortality at newly formed (and increasing) King Penguin colonies (Godoy and Borboroglu unpubl. data). As yet, no assessment has been made of the impact of fox predation, but given that these colonies are increasing and there is no reported adult mortality, it is unlikely to be significant. Rabbits Oryctolagus cuniculus are present at a few sites with potential to impact a small percentage of the global population. Rabbits have now been eradicated from Macquarie (Parks and Wildlife Service 2014) and the previous notable impact from herbivory, erosion and landslides on the island (Rounsevell and Binns 1991), is highly unlikely to recur. No population declines have been attributed to the impact of rabbits.
Conservation Actions Underway
The species is the subject of on-going international research but there are currently no special conservation activities. Human visitation to King penguin colonies is increasing and has the potential to increase disturbance, introduction of non-native species and transmission of disease. Although many operators have relevant biosecurity procedures in place, there is always a residual risk.
Conservation Actions Proposed
Conduct regular surveys to monitor population trends. Continue to improve on existing modelling work to better predict future population changes. Determine the use of marine habitats throughout the annual cycle for breeders and non-breeders. Model foraging habitat to determine the variables that govern distribution. Model foraging responses in years with varying sea surface temperatures. Examine the taxonomic status through population genetics. Instigate disease monitoring and monitor invasive species impact.
Management plans must include good biosecurity procedures (e.g. Commonwealth of Australia 2014) and preferably also strategies to deal with disease outbreaks and stipulate actions to prevent further spread (Cooper et al. 2009, Waller and Underhill 2007).
Text account compilers
Wienecke, B., Pearmain, L., Martin, R., Moreno, R., Bost, C., Trathan, P. N.
Ballard, G., Borboroglu, G., Chaigne, A., Crawford, R.J.M., DuBois, L., Makhado, A., Marteau, C., Pütz, K., Schmidt, A., Schneider, T., Simeone, A., Trathan, P. N., Wienecke, B. & Woehler, E.
BirdLife International (2021) Species factsheet: Aptenodytes patagonicus. Downloaded from http://www.birdlife.org on 21/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 21/10/2021.