Given an annual rate of decline of about 2% per year, there is considerable concern about the long-term viability of African Penguins in the wild. Presently more than ever before, zoos and aquariums are the Noahs ark for this species.
The African penguin population is currently less than 5% of the original population and still declining rapidly, with an 80% decline since the 1950s, and a 60% decline in the past decade. As a result, it has been classified as ENDANGERED by the IUCN, and is listed in Appendix II of CITES and the Bonn Convention for the conservation of migratory species.
The Minimum Viable Global Population is estimated to be 50 000 pairs; the current population is less than half of this critical threshold.
Statistics are frightening. On Dassen Island, averaged over the last 100 years, the collapse of the African Penguin population represents the equivalent of losing 1600 birds a week, or more than 2 birds per hour.
The causes of this precipitous decline are numerous, and mainly human-induced.
WHAT HAS CAUSED THE DECLINE IN THEIR NUMBERS?
EGG COLLECTION – Initially, the decline was due mostly to the exploitation of penguin eggs for food. This practise has been banned, but did begin the decline. Collectors would go into the nesting areas and remove all the eggs, then wait for fresh eggs to be laid, and remove these to be sold as delicacies.
GUANO COLLECTION For centuries, the guano (penguin poop) collected on the islands and formed a layer metres thick in some parts. This guano was used by the penguins they would burrow into the material and use the burrows as safe well insulated nest sites. We collected the guano off the islands to use as fertilizer. The result is that the penguins were left vulnerable to the elements and predators. Climate change with increased temperatures and unpredictable weather does nothing to aid this concern.
OVER FISHING – threats include competition with commercial fisheries for pelagic fish prey,
OIL POLLUTION Large spills are catastrophic for the penguins. Not only are the individuals affected, there is also the disturbance to their breeding and natural cycle. Small spills from locals cleaning out their boat bilges also cause problems.
OTHER THREATS – competition with Cape Fur Seals. Feral cats are present and pose a problem at a few of the colonies. African Penguins also face predation of eggs and chicks by avian predators such as Kelp Gulls and Sacred Ibises, while natural terrestrial predators, such as mongooses, genets and leopard are present at the mainland colonies.
AFRICAN PENGUIN FACTS
Distribution – The African penguin is only found on the Southern African coastline. Nowhere else in the world. Its breeding range extends from Hallams Bird Island, off central Namibia, to Bird Island in Algoa Bay. Non-breeding birds disperse from Southern Angola to Kwazulu-Natal, and have even been sighted as far as Mozambique. There are 27 extant breeding colonies, eight islands and one mainland site along the coast of southern Namibia, 10 islands and two mainland sites along the coast of the Western Cape Province (South Africa), and six islands in Algoa Bay (Eastern Cape Province, South Africa). Breeding no longer occurs at 10 localities where it formerly may have occurred.
The Algoa Bay population comprises almost half of the global population, which stands at some 80 000 individuals. Its distribution coincides roughly with the cold, nutrient rich, Benguela Current.
Features – African Penguins grow to 6870 cm (26.727.5 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. 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. Males tend to be larger with heavier bills, but these differences can usually only be seen when a pair is seen together. Females have been described as relatively pear-shaped. Juveniles differ from adults by being entirely blue-grey above, and lacking the white face markings and black breast band of the adults.
Their distinctive black and white colouring is helpful to provide camouflagewhite for underwater predators looking upwards and black for predators looking down onto the dark water.
Their scientific name is Spheniscus Demersus. Spheniscus is a diminutive of the Greek word spen, meaning a wedge, which refers to their streamlined swimming shape, while demersus is a Latin word meaning plunging.
Diet – The birds eat primarily shoaling pelagic fish. This includes anchovies, sardines, horse mackerel and on occasion, squid and crustaceans. In the different habitats, the birds eat slightly different diets. The penguins have an extremely high metabolic rate. Captive penguins have been recorded eating an average of around 300grams a day. Before a moult, one penguin has been recorded eating 750 grams of fish in one go. This is remarkable when you consider that the birds weigh between 2.5 to 6 kilograms.
Hunting penguins – The penguins have been clocked swimming at around 20kms an hour when on the hunt. They have been noted holding their breath for up to two and a half minutes, and have been recorded diving regularly to depths of 30m. They have also been noted swimming extraordinary distances to find their food. This will also vary depending where the birds home ground is. On the west coast, a typical foraging trip could range from 30 to 70 km. for a single trip. On the south coast, foraging birds cover an average of 110 km. per trip.
Sexual maturity. – At around 4 years of age, they begin to breed, however there have been records of the penguins starting as early as age 2, and as late as age 6. African Penguins are monogamous, and the same pair will generally return to the same colony, and often the same nest site each year. About 80 to 90% of pairs remain together in consecutive breeding seasons, and some are known to have remained together for over 10 years.
Breeding – African Penguins usually lay two eggs at a time. The incubation period is 35 to 42 days, with the male and female sharing the duty of looking after the eggs, taking turns to fish or incubate the eggs. The length of a nest shift is dependant on the availability of food at the time, but is typically about two and a half days.
Both parents assist to raise the chicks. For the first 15 days the chicks are constantly brooded by one of the adults. After this, the chicks attain full control over their body temperature. However, at this stage the chicks are still at risk from predators, and the adults continue to guard the chicks until they are about 30 days old, after which both parents can go to sea simultaneously.
Chicks that are left alone often form nursery groups creating safety in numbers. This may also serve to reduce attacks on chicks from other adults.
Fledging – African Penguin chicks leave the nest after loosing all their down feathers. This can happen anytime from 60 to 130 days of age. In recent times, there have been records of the chicks fledging later. This may be a as result of less food around. The adults continue to feed chicks while the young are still present at the colony. When the young eventually leave the colony, they do so without their parents. These juveniles remain away from their natal colonies for anything from 12 to 22 months, after which time they return, normally to their natal colony, to moult into adult plumage and find a mate.
Moult – The penguins change all their feathers once a year. This process means that during the moult period, they are without their waterproofing, and so unable to fish. In South Africa most penguins moult from November to January, while in Namibia most moult in April and May.
The entire moult takes about 20 days to complete, with the feather-shedding period lasting up to 13 days. Prior to the moult the penguins spend about five weeks laying down fat deposits, but lose almost half their body weight during the moult process. At the end of the moult the penguins return to sea and spend about six weeks fattening up again.
LIFE CYCLE of the AFRICAN PENGUIN – thank you Michelle of Bayworld