African penguin

The African penguin (Spheniscus demersus), also known as the Cape penguin or South African penguin, is a species of penguin confined to southern African waters. Like all extant penguins, it is flightless, with a streamlined body and wings stiffened and flattened into flippers for a marine habitat. Adults weigh an average of 2.2–3.5 kg (4.9–7.7 lb) and are 60–70 cm (24–28 in) tall. The species has distinctive pink patches of skin above the eyes and a black facial mask. The body upperparts are black and sharply delineated from the white underparts, which are spotted and marked with a black band. The pink glands above their eyes help them with thermoregulation. To cope with changing temperatures, blood is sent to the glands to be cooled by the air.[2]

African penguin
African penguin side profile.jpg
At Boulders Beach in Cape Town, South Africa
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Sphenisciformes
Family: Spheniscidae
Genus: Spheniscus
Species:
S. demersus
Binomial name
Spheniscus demersus
African penguin distribution en.jpg
Distribution of the African penguin
Synonyms
  • Diomedea demersa Linnaeus, 1758

The African penguin is a pursuit diver, and feeds primarily on fish and squid. Once extremely numerous, the African penguin is declining rapidly due to a combination of several threats and is classified as endangered. It is a charismatic species and is popular with tourists. Other vernacular names of the species include black-footed penguin and jackass penguin, due to the species' loud, donkey-like bray,[3] although several related species of South American penguins produce the same sound.

TaxonomyEdit

The African penguin was one of the many bird species originally described by Carl Linnaeus in the landmark 1758 10th edition of his Systema Naturae, where he grouped it with the wandering albatross on the basis of its bill and nostril morphology and gave it the name Diomedea demersa.[4]

The African penguin is a banded penguin, placed in the genus Spheniscus. The other banded penguins are the African penguin's closest relatives, and are all found mainly in the Southern Hemisphere: the Humboldt penguin and Magellanic penguins found in southern South America, and the Galápagos penguin found in the Pacific Ocean near the equator. All are similar in shape, colour and behaviour.

The African penguin is a member of the class Aves and the order Sphenisciformes. It belongs to the penguin family Spheniscidae, and is classified as Spheniscus demersus. The genus to which the African penguin belongs, Spheniscus, derives its name from the Ancient Greek word sphen ('wedge'), referring to their streamlined body shape. Its species name, demersus, is a Latin word for "plunging".[5]

Penguin colony at Betty's Bay

DescriptionEdit

 
African penguin diving in Siam Center, Bangkok, Thailand
 
African penguin skeleton at the Museum of Osteology

African penguins grow to 60–70 cm (24–28 in) tall and weigh between 2.2–3.5 kg (4.9–7.7 lb).[6] They have a black stripe and black spots on the chest, the pattern of which is unique to each penguin, like human fingerprints. The sweat glands above the eyes cool the birds' blood, and as the temperature rises, increased blood flow causes the glands to get more pink.[7] This species exhibits slight sexual dimorphism; the males are slightly larger than the females and have longer beaks.[8] Juveniles do not possess the bold, delineated markings of the adult, but instead have dark upperparts that vary from greyish-blue to brown; the pale underparts lack both spots and the band. The beak is more pointed than that of the Humboldt. The African penguin's colouring is a form of protective colouration known as countershading. The white undersides of the birds are difficult to spot by predators under the water, and the penguins' black backs blend in with the water when viewed from above.

African penguins resemble and are thought to be related to the Humboldt, Magellanic, and Galápagos penguins.[2] African penguins have a very recognisable appearance, with a thick band of black that in the shape of an upside-down horseshoe. They have black feet and black spots that vary in size and shape between individuals. Magellanic penguins share a similar bar marking that often confuses the two; Magellanics have a double bar on the throat and chest, whereas the African has a single bar. These penguins have the nickname "jackass penguin", which comes from the loud noises they make.

Distribution and habitatEdit

The African penguin is only found on the south-western coast of Africa, living in colonies on 24 islands between Namibia and Algoa Bay, near Port Elizabeth, South Africa.[1] It is the only penguin species that breeds in Africa, and its presence gave name to the Penguin Islands.

 
Penguin with chicks, Boulders Beach, South Africa

Two colonies were established by penguins in the 1980s on the mainland near Cape Town, namely Boulders Beach near Simon's Town and Stony Point in Betty's Bay. Mainland colonies likely became possible only in recent times due to the reduction of predator numbers, although the Betty's Bay colony has been attacked by leopards.[9][10] The only other mainland colony is in Namibia, but it is not known when it was established.

Boulders Beach is a tourist attraction due the beach, swimming and the penguins.[11][12] The penguins will allow people to approach them as close as a metre.

Breeding populations of African penguins are being kept in numerous zoos worldwide. No colonies are known outside the south-western coast of Africa, although vagrants (mostly juveniles) may occasionally be sighted beyond the normal range.

PopulationEdit

Roughly 4 million penguins existed at the beginning of the 19th century. Of the 1.5 million African penguins estimated in 1910, only some 10% remained at the end of the 20th century. African penguin populations, which breed in Namibia and South Africa, have declined by 95 percent since pre-industrial times.[13]

Today, their breeding is largely restricted to 24 islands from Namibia to Algoa Bay, South Africa,[14] with the Boulders Beach colony being an exception to this rule.

The total population fell to approximately 150,000–180,000 in 2000.[15][16] Of those, 56,000 belonged to the Dassen Island colony and 14,000 to the Robben Island colony.[17] The colony at Dyer Island in South Africa fell from 46,000 in the early 1970s to 3,000 in 2008.[18]

In 2008, 5,000 breeding pairs were estimated to live in Namibia.

In 2010, the total African penguin population was estimated at 55,000. At this rate of decline, the African penguin is expected to be extinct in the wild by 2026.[19]

In 2012, about 18,700 breeding pairs were estimated to live in South Africa, with the majority on St. Croix Island in Algoa Bay.[1][20]

The total breeding population across both South Africa and Namibia fell to a historic low of about 20,850 pairs in 2019.[21]

BehaviourEdit

DietEdit

African penguins forage in the open sea, where they pursue pelagic fish such as sardines and anchovies (specifically the Southern African anchovy),[22] and marine invertebrates such as squid and small crustaceans.[23] Penguins normally swim within 20 km (12 mi) of the shore.[6] A penguin may consume up to 540 grams (1.19 lb) of prey every day,[24] but this may increase to over 1 kg (2.2 lb) when raising older chicks.[23]

Due to the collapse of a commercial pilchard (sardine) fishery in 1960, the African penguin's diet has shifted towards anchovies to some extent, although available pilchard biomass is still a notable determinant of penguin population development and breeding success. While a diet of anchovy appears to be generally sufficient, it is not ideal due to anchovies' lower concentrations of fat and protein. Penguin diet changes throughout the year; as in many seabirds, it is believed that the interaction of diet choice and breeding success helps the penguins maintain their population size. Although parent penguins are protective of their hatchlings, they will not incur nutritional deficits themselves if prey is scarce and hunting requires a greater time or energy commitment. This may lead to higher rates of brood loss under poor food conditions.

When foraging, African penguins carry out dives that reach an average depth of 25 m (82 ft) and last for 69 s, although a maximum depth of 130 m (430 ft) and duration of 275 s has been recorded.[25]

BreedingEdit

 
Egg from the collection of Museum Wiesbaden
 
Nesting burrows of the African penguin, Boulders Beach (2017)

The African penguin is monogamous.[5] It breeds in colonies, and pairs return to the same site each year. The African penguin has an extended breeding season,[5] with nesting usually peaking from March to May in South Africa, and November to December in Namibia.[22] A clutch of two eggs are laid either in burrows dug in guano, or scrapes in the sand under boulders or bushes. Incubation is undertaken equally by both parents for around 40 days. At least one parent guards the chicks for about one month, whereafter the chicks join a crèche with other chicks and both parents head out to sea to forage each day.

Chicks fledge at 60 to 130 days, the timing depending on environmental factors such as the quality and availability of food. The fledged chicks then go to sea on their own, where they spend the next one to nearly two years. They then return to their natal colony to molt into adult plumage.[5]

When penguins molt, they are unable to forage as their new feathers are not yet waterproof; therefore, they fast over the entire molting period.[5] African penguins take around three weeks to molt, and lose almost half their body weight by using up their fat reserves in the process.[26]

Female African penguins remain fertile for 10 years. African penguins spend most of their lives at sea until it comes time for them to lay their eggs. Due to high predation on the mainland, African penguins will seek protection on offshore islands, where they are safer from larger mammals and natural challenges. These penguins usually breed during the winter when temperatures are lower. African penguins often will abandon their eggs if they become overheated in the hot sun, and abandoned eggs do not survive the heat. Ideally, eggs are incubated in a burrow dug into the guano layer (which provides suitable temperature regulation), but the widespread human removal of guano deposits has rendered this type of nest unfeasible at many colonies. To compensate, penguins dig holes in the sand, breed in the open, or make use of nest boxes if they are provided. The penguins spend three weeks on land to provide for their offspring, after which chicks may be left alone during the day while the parents forage. The chicks are frequently killed by predators or succumb to the hot sun. The eggs are three to four times bigger than hen's eggs. Parents usually feed hatchlings during dusk or dawn.

In 2015, when foraging conditions were favorable, more male than female African penguin chicks were produced in the colony on Bird Island. Male chicks also had higher growth rates and fledging mass, and therefore may have higher post-fledging survival than females. This, coupled with higher adult female mortality in this species, may result in a male biased adult sex ratio and may indicate that conservation strategies focused on benefiting female African penguins may be necessary.[27]

PredationEdit

The average lifespan of an African penguin is 10 to 27 years in the wild, and up to 30 in captivity.[28]

Primary predators of African penguins include sharks and fur seals. While nesting, kelp gulls, mongooses, caracals, Cape genets and domestic cats may prey on the penguins and their chicks.[29][30] Pressure from terrestrial predators is higher if penguins are forced to breed in the open in the absence of suitable burrows or nest boxes.

Threats and conservationEdit

 
African penguin at the New England Aquarium
(video) African penguin swims at an aquarium in Tokyo

Historical exploitationEdit

African penguin eggs were considered a delicacy, and were still being collected for sale as recently as the 1970s. In the 1950s, they were being collected from Dassen Island and sold in nearby towns.[31] In 1953, 12,000 eggs were collected.[32] In the late 1950s, some French chefs expressed interest in recipes including African penguin eggs collected from the islands off South Africa's west coast, and placed annual orders for small quantities.[33][34][35] In the mid 1960s, eggs were collected in the thousands and sold by the dozen,[36] with each customer limited to two dozen eggs in total.[37]

The practice of collecting African penguin eggs involved smashing those found a few days prior to a collecting effort to ensure that only freshly laid eggs were sold. This added to the drastic decline of the African penguin population around the Cape coast, a decline which was hastened by the removal of guano from islands for use as fertiliser, eliminating the burrowing material used by penguins.[38]

Oil spillsEdit

Penguins remain susceptible to pollution of their habitat by petrochemicals from spills, shipwrecks and cleaning of tankers while at sea. Accounts of African penguins impacted by oil date back to the 1930s.[39] In 1948, the tanker Esso Wheeling sank, subsequently oiling and killing thousands of penguins of the Dyer Island colony.[40] In 1953, dead penguins were among a range of dead birds, fish and other marine life that washed ashore after the tanker Sliedrecht was holed and spilled oil near Table Bay.[41] In 1971, the SS Wafra oil spill impacted the African penguin colony of Dyer Island. In 1972, oil spilled following the Oswego-Guardian and Texanita collision oiled roughly 500 penguins.[42] In 1975, newspapers reported that oil pollution from shipwrecks and the pumping of bilges at sea had killed tens of thousands of African penguins. At the time, the Dassen Island colony was being passed by 650 oil tankers each month[43] because the Suez Canal had become blocked with wrecked vessels, thus increasing maritime traffic past the Cape of Good Hope.[42]

In 1979, an oil spill prompted the collection and treatment of 150 African penguins from St. Croix Island near Port Elizabeth. The animals were later released at Robben Island and four of them promptly swam back to St. Croix Island, surprising scientists.[44][45]

In 1983, the exposure of penguins of Dassen Island to the oil slick from the Castillo de Bellver was also a topic of concern given the penguins' conservation status at the time, but owing to prevailing wind and current, only gannets were oiled.[46]

1994 MV Apollo Sea disasterEdit

African penguin casualties were significant following the sinking of the MV Apollo Sea and subsequent oil slick in 1994. 10,000 penguins were collected and cleaned, of which less than half survived.[47]

2000 MV Treasure crisisEdit

Disaster struck on 23 June 2000, when the iron ore tanker MV Treasure sank between Robben Island and Dassen Island, South Africa. It released 400–1,000 tonnes (390–980 long tons; 440–1,100 short tons) of fuel oil, causing an unprecedented coastal bird crisis and oiling 19,000 adult penguins at the height of the best breeding season on record for this vulnerable species.[48] The oiled birds were brought to an abandoned train repair warehouse in Cape Town to be cared for. An additional 19,500 un-oiled penguins were removed from Dassen Island and other areas before they became oiled, and were released about 800 kilometres east of Cape Town, near Port Elizabeth. This gave workers enough time to clean up the oiled waters and shores before the birds could complete their long swim home (which took the penguins between one and three weeks). Some of the penguins were named and radio-tracked as they swam back to their breeding grounds. Tens of thousands of volunteers helped with the rescue and rehabilitation process, which was overseen by the International Fund for Animal Welfare (IFAW) and the South African Foundation for the Conservation of Coastal Birds (SANCCOB), and took more than three months to complete. This was the largest animal rescue event in history; more than 91% of the penguins were successfully rehabilitated and released – an amazing feat that could not have been accomplished without such a tremendous international response.[49]

Due to the positive outcome of African penguins being raised in captivity after tragedies such as the Treasure oil spill, the species is considered a good "candidate for a captive-breeding programme which aims to release offspring into the wild"; however, worry about the spread of new strains of avian malaria is a major concern in the situation.[50]

Bringing the birds inland led to the exposure of penguins to parasites and vector species such as mosquitoes, including mosquitoes carrying avian malaria, which has caused 27% of the rehabilitated penguin deaths annually.[51]

2016 & 2019 Port of NgquraEdit

Small scale oil spills (of less than 400 litres (110 US gal)) have occurred at the Port of Ngqura since bunkering activities started there in 2016. Bunkering is a ship refueling process that can result in oil spills and oil slicks entering the water. Hundreds of African penguins have been harmed following these spills,[52] due to the port's close proximity to penguin rookeries on St. Croix Island and seabird habitat on neighbouring Jahleel and Brenton Islands.

Competition with fisheriesEdit

Commercial fisheries of sardines and anchovy, the two main prey species of the penguins, have forced these penguins to search for prey farther offshore, as well as having to switch to eating less nutritious prey.[13] Restricting commercial fishing in the immediate vicinity of colony sites such as Robben Island for short periods (3 years) was shown to markedly improve penguin breeding success. Longer closure periods and closures near other colonies are being evaluated.[53][54][55]

Conservation statusEdit

The African penguin is one of the species to which the African-Eurasian Waterbird Agreement (AEWA) applies. In September 2010, it was listed as endangered under the US Endangered Species Act.[13] As of 2018, the African penguin is listed as endangered on the IUCN Red List. Its population is approximately 50,000 birds and declining.[56]

Mediation effortsEdit

Many organisations such as SANCCOB, Dyer Island Conservation Trust, SAMREC and Raggy Charters with the Penguin Research Fund in Port Elizabeth are working to halt the decline of the African penguin. Measures include monitoring population trends, hand-rearing and releasing abandoned chicks, establishing artificial nests and proclaiming marine reserves in which fishing is prohibited.[1] Some colonies (such as on Dyer Island) are suspected to be under heavy pressure from predation by Cape fur seals and may benefit from the culling of individual problem animals,[54][57] which has been found effective (although requiring a large amount of management effort) in trials.[58]

Established in 1968, SANCCOB is currently the only organisation mandated by the South African government to respond to crises involving seabirds along South Africa's coastline and is internationally recognised for the role it played during the MV Treasure oil spill. A modeling exercise conducted in 2003 by the University of Cape Town's FitzPatrick Institute of African Ornithology found that rehabilitating oiled African penguins has resulted in the current population being 19 percent larger than it would have been in the absence of SANCCOB's rehabilitation efforts.[59]

In February 2015, the Dyer Island Conservation Trust opened the African Penguin and Seabird Sanctuary (APSS) in Gansbaai, South Africa.[60] The centre was opened by then-Department of Tourism minister Derek Hanekom,[61] and will serve as a hub for seabird research carried out by the Dyer Island Conservation Trust. The centre will also run local education projects, host international marine volunteers, and seek to improve seabird handling techniques and rehabilitation protocols.

CaptivityEdit

 
African penguin at the Dallas World Aquarium

African penguins are a commonly seen species in zoos across the world. Because they do not require particularly low temperatures, they are often kept in outside enclosures. They adapt fairly well to this captive environment, and are rather easy to breed compared to other species of the family. In Europe, the breeding program EEP is regulated by Artis Royal Zoo in the Netherlands, whilst in the United States, the SSP program is coordinated by the Smithsonian National Zoological Park. The idea is to create a backup captive population, as well as to aid in the conservation of the population in its natural habitat. Between 2010 and 2013, American zoos spent $300,000 on in-situ (wild population) conservation.[62][63]

See alsoEdit

GalleryEdit

ReferencesEdit

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