The African penguin Spheniscus demersus, endemic to southern Africa, has seen a large decrease in numbers during the 20th century. The species dropped from about 1.5million adults to less than 36, 000 and has now been classified as "endangered".
The African penguin is now facing extinction due to ever decreasing numbers. Historically, the decrease in numbers was from egg and guano harvesting. However, since these harvestings have stopped, marine pollution and depleted food sources from over fishing has led to a continuous decrease in penguin numbers
Penguins breed at 29 locations in South Africa and Namibia (19 in SA). Over the last 50 years, the population has decreased by about 80%. The population size in 2011 was approximately 20,000 pairs. In 2012 this went down to about 18,600 pairs.
Penguin numbers are often reported as breeding pairs because they do not raise chicks on their own.
What can I do to save the penguin?
- Only eat fish on the SASSI green list
- Don’t use plastic shopping bags rather buy reusable bags
- Don’t use plastic straws
- Use water sparingly
- Get involved in coastal clean ups
- Do not litter and become environmentally conscious
- Donate a breeding nest through Dyer Island Conservation Trust http://www.dict.org.za
- Support your local penguin colonies (Stony Point, Dyer Island, Dassen Island) as that money is used for penguin research
- Follow the 2013 Penguin Promises Waddle for a Week
African Penguin Facts
African Penguins can grow up to 68-70 cm tall and weigh between two and five kilograms. 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. This makes the pink colour appear more prominent on the penguin.
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 camouflage–white 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.
Off South Africa, anchovy and sardine are the main prey of African penguins. They contributed 50-90% by mass of their diet in six studies conducted between 1953 and 1992, and 83-85% by number of prey items eaten in two studies between 1977 and 1985.
The also eat mullet, horse mackerel and round herring. On the south coast, squid can also feature in their diet. Sardine and anchovy are important because they are very rich in energy and lipids that penguins and their chicks need to grow and survive.
They forage singly or in small groups, often in association with other seabirds such as Sooty Shearwaters, Cape Gannets, Cape Cormorants, Kelp Gulls, and terns. When hunting in groups they work together to round up a fish school and compress it. They can dive up to 130m but usually only around 50m.
African penguins forage by day, with most food being caught between 10am and 6pm. They often remain at sea at night but seldom feed then.
Breeding can occur through the year, but there is usually a peak season. The peak occurs at different times for different colonies.
Peak egg-laying times for selected colonies:
- Malgas, Marcus and Stony Point: February to August
- Dassen Island: June and November to December
- Robben Island: January to August
- St Croix Island: January
Download: African penguin.pdf
The establishment of nests takes several weeks and incubation lasts about 40 days. African penguins generally mate for life and breed at the same colony (often even the same nest) every year. They lay up to two eggs, which take about 40 days to hatch. The time it takes the chicks to fledge and leave the nest depends on how much food they get and how quickly the grow, but can be between 60 and 130 days.
Effect of food on breeding success
The relationship between penguin breeding success and survival is complex and differs from place to place. They also need different species of fish at different stages of their life cycle. A lot of research has been undertaken at Robben Island. The results of this research suggest that if penguins do not find enough food before breeding, then they will decide not to breed. For Robben Island, sardine is thought to be most important during the pre-breeding period. Breeding success (number of chicks raised per pair) is related to anchovy catch within 56km of Robben Island (using fish catch as a proxy for fish abundance.
Other important life stages
When penguins moult, they replace all their feathers at the same time as their old feathers become damaged and less waterproof. They stay on land for about three weeks and cannot go in the water and so cannot forage. They can lose about half of their body weight during this time. So they need to find enough food before moulting to survive this period as well as find enough food after they have moulted to regain their body condition.
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