Friday, 22 June 2012

African Penguin

The African Penguin (Spheniscus demersus), also known as the Black-footed Penguin is a species of penguin, confined to southern African waters. It is known as Brilpikkewyn in Afrikaans, Inguza or Unombombiya in Xhosa, Manchot Du Cap in French and Pingüino Del Cabo in Spanish. It is also widely known as the "Jackass" Penguin for its donkey-like bray, although several species of South American penguins produce the same sound.


  

 

 

 Taxonomy

 

The African Penguin was one of the many bird species originally described by 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.
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.

Etymology

 

The genus to which the African Penguin belongs to, Spheniscus, derives from the Ancient Greek word sphen, which means wedge. This refers to their streamlined body shape. Its species name, demersus, is a Latin word for "plunging".

Description

African Penguin diving

  African Penguins grow to 68–70 cm (26.7–27.5 in) tall and weigh between 2 and 5 kg (4.4 and 11 lb). They have a black stripe and black spots on the chest, the pattern of spots being unique for every penguin, like human fingerprints. They have pink glands above their eyes, which are used for thermoregulation. The hotter the penguin gets, the more blood is sent to these glands so it may be cooled by the surrounding air, thus making the glands more pink. This species exhibits slight sexual dimorphism: the males are larger than the females and have larger beaks. The beak is more pointed than that of the Humboldt. Their distinctive black and white colouring is a vital form of camouflage called countershading– white for underwater predators looking upwards and black for predators looking down onto the dark water.

Distribution

 

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

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 probably only became possible in recent times due to the reduction of predator numbers, although the Betty's Bay colony has been attacked by leopards. The only other mainland colony is in Namibia, but it is not known when this was established.
Boulders Beach is a tourist attraction, for the beach, swimming and the penguins. The penguins will allow people to approach them as close as a metre (three feet).

Biology

 

Diet

African Penguins forage in the open sea, where they pursue pelagic fish such as pilchards and anchovies (e.g. Engraulis capensis), and marine invertebrates such as squid and small crustaceans. A penguin may consume up to 540 grams of prey every day, but this may increase to over 1 kg when raising older chicks.

Breeding

The African Penguin is monogamous. It breeds in colonies, and pairs return to the same site each year. The African Penguin has an extended breeding season, with nesting usually peaking from March to May in South Africa, and November and December in Namibia. 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 about 40 days. At least one parent guards the chicks until about 30 days, whereafter the chick joins a creche 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 quality and availability of food. The fledged chick then go to sea on their own and return to their natal colony after a lengthy time period of 12-22 months to molt into adult plumage.
When penguins molt, they are unable to forage as their new feathers are not waterproof yet; therefore they fast over the entire molting period, which in African Penguins takes about 20 days.

Predation

The average lifespan of an African Penguin is 10 to 27 years in the wild, and possibly longer in captivity. However, the African Penguin may often fall to predators.
Their predators in the ocean include sharks, Cape Fur Seals and, on occasion, orcas. Land-based enemies include mongooses, genets, domestic cats, and the Kelp Gull which steals their eggs and newborn chicks.

Conservation

 

Threats

African Penguin at the New England Aquarium.
 
 
Spheniscus demersus 2010.ogv
African Penguin swims at an aquarium in Tokyo.

Of the 1.5-million African Penguin population 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 preindustrial times.
Commercial fisheries have forced these penguins to search for prey farther off shore, as well as making them eat less nutritious prey, since their preferred prey has become scarce. Global climate change is also affecting these penguins' prey abundance.
As recently as the mid-twentieth century, penguin eggs were considered a delicacy and were still being collected for sale. Unfortunately, the practice was to smash eggs found a few days prior to gathering, to ensure that only fresh ones were sold. This added to the drastic decline of the penguin population around the Cape coast, a decline which was hastened by the removal of guano from islands for use as fertilizer, eliminating the burrowing material used by penguins. Penguins remain susceptible to pollution of their habitat by petrochemicals from spills, shipwrecks and cleaning of tankers while at sea.
Disaster struck on 23 June 2000, when the iron ore tanker MV Treasure sank between Robben Island and Dassen Island, South Africa. It released 1,300 tons of fuel oil, causing an unprecedented coastal bird crisis, oiling 19,000 adult penguins at the height of the best breeding season on record for this vulnerable species. 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 1 and 3 weeks). Some of the penguins were named and radio-tracked as they swam back to their breeding grounds. Tens of thousands of volunteers descended upon Cape Town to help with the rescue and rehabilitation process, which was overseen by IFAW (International Fund for Animal Welfare) 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.

Conservation status

 

The African Penguin is one of the species to which the Agreement on the Conservation of African–Eurasian Migratory Waterbirds (AEWA) applies. The African Penguin is listed in the Red Data Book as an endangered species.
In September 2010, the African Penguin was listed as endangered under the U.S.A Endangered Species Act.
Roughly 4 million penguins existed at the beginning of the last century. The total population fell to 200,000 in the year 2000; ten years later, in 2010, the number was estimated to be only at 55,000. If this decline is not halted, the African Penguin is expected to be extinct within 15 years.
5,000 breeding pairs were estimated to live in Namibia in 2008; in 2009, about 21,000 pairs were estimated to live in South Africa.

Mediation efforts

 

Many organisations such as SANCCOB, Dyer Island Conservation Trust, and the government are working tirelessly to halt the decline of the African Penguin, through various measures: monitoring population trends, hand-rearing and releasing abandoned chicks, setting up artificial nests, and proclaiming marine reserves where fishing is prohibited.