The
African penguin (
Spheniscus demersus), also known as the
jackass penguin and
black-footed penguin is a species of
penguin, confined to southern African waters. It is also widely known as the "jackass" penguin for its
donkey-like bray,
[2]
although several related species of South American penguins produce the
same sound. Like all extant penguins it is flightless, with a
streamlined body, and wings stiffened and flattened into flippers for a
marine habitat. Adults weigh on average 2.2–3.5 kg (4.9–7.7 lb) and are
60–70 cm (24–28 in) tall. It 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 gland above their eyes helps them to
cope with changing temperatures. When the temperature gets hotter, the
body of the African penguin sends more blood to these glands to be
cooled by the air surrounding it. This then causes the gland to turn a
darker shade of pink.
[3]
The African penguin is a
pursuit diver
and feeds primarily on fish and squid. Once extremely numerous, the
African penguin is declining due to a combination of threats and is
classified as endangered. It is a charismatic species and is popular
with tourists.
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.
[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. It is classified as
Spheniscus demersus. 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".
[5]
Description
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
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.
[7] This species exhibits slight
sexual dimorphism: the males are larger than the females and have larger 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. 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. African penguins look similar and are
thought to be related to the Humboldt, Magellanic, and Galapagos
penguins.
[9]
African penguins have a very recognisable appearance with a thick band
of black that is in the shape of an upside-down horseshoe. They have
black feet and unique black spots that vary in size and shape per
penguin. Magellanic penguins share a similar characteristic that often
confuses the two, the similarity is a double bar on the throat and
chest. These penguins have the nickname of "jackass penguin" which comes
from the loud noises they make.
Distribution and habitat
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.
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.
[10][11] The only other mainland colony is in Namibia, but it is not known when it was established.
Boulders Beach is a tourist attraction, for the beach, swimming and the penguins.
[12][13] 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.
Population
Roughly
4 million penguins existed at the beginning of the 19th century. Of the
1.5-million population of 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.
[14]
The total population fell to 200,000 in 2000. 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.
[15]
5,000 breeding pairs were estimated to live in Namibia in 2008; in
2012, about 18,700 pairs were estimated to live in South Africa, with
the majority of those numbers on St Croix Island in Algoa Bay.
[1][16]
Behaviour
Diet
African penguins forage in the open sea, where they pursue
pelagic fish such as
pilchards and anchovies (e.g.
Engraulis capensis),
[17] and marine invertebrates such as
squid and small
crustaceans.
[18] Penguins normally swim within 20 km of the shore.
[6] A penguin may consume up to 540 grams of prey every day,
[19] but this may increase to over 1 kg when raising older chicks.
[18]
Due to the collapse of a commercial pilchard fishery in 1960, African
penguin 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 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 greater time or energy commitment. This may lead to
higher rates of brood loss under poor food conditions.
Breeding
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 and December in Namibia.
[17] 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
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 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.
[5]
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.
[5]
African penguin females 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 the high predation by larger mammals on the mainland,
the penguins will go offshore to an island for protection from mammals
and natural challenges. African penguins usually breed during the
African winter when temperatures are lower. Ideally, eggs are incubated
in a burrow dug into the guano layer, which provides a suitable
temperature regulation, but the widespread human removal of guano
deposits has rendered this type of nest unfeasible at most colonies. To
compensate, penguins dig holes in the sand, breed in the open, or make
use of nest boxes if such 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 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, indicating that conservation strategies
focused on benefiting female African Penguins may be necessary.
[20]
Predation
The average lifespan of an African penguin is 10 to 27 years in the wild, and can live up to 30 in captivity.
[21] However, the African penguin may often fall to predators.
Predators in the ocean include
sharks,
Cape fur seals and, on occasion,
orcas. Land-based enemies include
mongooses,
genets,
caracals, leopards, domestic cats, and the
kelp gull which steals their eggs and newborn chicks.
[22]
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 conservation
(video) African penguin swims at an aquarium in
Tokyo
Historical exploitation
As
recently as the mid-20th 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 fertiliser, eliminating the burrowing material used by penguins.
[23]
Oil spills
Penguins remain susceptible to pollution of their habitat by
petrochemicals from spills, shipwrecks and cleaning of tankers while at sea.
2000 MV Treasure crisis
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,
[24]
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 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
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.
[25]
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, worries about the spread of new strains of
avian malaria is a major concerning factor in the situation.
[26]
Bringing the birds inland led to the exposure of parasites and vector
species such as mosquitoes, specifically avian malaria which has caused
27% of the rehabilitated penguins deaths annually.
[27]
1994 MV Apollo Sea disaster
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.
[28]
Competition by fisheries
Commercial fisheries
of sardines and anchovy, which constitute the two main prey species of
the penguins, have forced these penguins to search for prey farther off
shore, as well as having to switch to eat less nutritious prey.
[14] Experimental closures of the immediate vicinity of colony sites at e.g.
Robben Island
to fishery for short periods (3 years) were shown to result in marked
benefits to penguin breeding success, and longer closure periods and
their extension to further colonies are being evaluated.
[29][30]
Conservation status
The African penguin is one of the species to which the
Agreement on the Conservation of African–Eurasian Migratory Waterbirds (
AEWA) applies. In November 2013 the African penguin was listed as endangered on the
IUCN Red List of Threatened Species.
[1] In September 2010 it was listed as endangered under the US
Endangered Species Act.
[14]
Mediation efforts
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 (e.g. 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
[30][31] which has been found effective (although requiring a large amount of management effort) in trials.
[32]
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 when more than 20 000 African penguins were oiled when the ship sank between
Robben Island and
Dassen Island.
A modeling exercise conducted in 2003 by the University of Cape Town's
Percy Fitz Patrick 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.
[33]
In February 2015, the Dyer Island Conservation Trust opened the
African Penguin and Seabird Sanctuary (APSS) in Gansbaai, South Africa.
[34] The centre was opened by the Department of Tourism Minister Derek Hanekom
[35]
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.
