A. J. Williams

Trends of African penguin Spheniscus demersus populations in the 20th century

The entire nesting population of African penguins Spheniscus demersus was about 575 000 adults at the start of the 20th century. Numbers halved by the 1950s and continued to fall to about 220 000 by the late 1970s and about 180 000 by the early 1990s. In Namibia, there has been a 30% reduction since the late 1970s, the most severe declines being in the south, where colonies continue to decrease. Populations at Mercury, lchaboe and Halifax islands now appear to be stable. In South Africa, numbers fell by 17% between the late 1970s and early 1990s, with especially severe decreases near Saldanha Bay and at Dassen and Dyer islands. These decreases have been arrested, except at Dyer Island. Three new colonies were established in the Western Cape in the early 1980s and supported about 10 000 adult birds in 1994. At islands in Algoa Bay, numbers of adults increased by nearly 30 000 between the late 1970s and the early 1990s, with large increases at St Croix and Bird islands. Ongoing deterioration in the status o...

The Prince Edward Islands: A sanctuary for seabirds in the Southern Ocean

Abstract This paper reviews the breeding distribution and numerical status of selected species of seabirds at 23 oceanic island groups in the Southern Ocean (between latitudes 35 and 70°S), based on census data and population estimates which have become available through increased scientific endeavour in the region during the last 15 years or so. The paper focuses on the avifauna of the Prince Edward islands, in the southern Indian Ocean, and points to the importance of these islands as a breeding station and sanctuary for seabirds. Only one oceanic island group, the Crozets, contains more species of breeding seabirds than the Prince Edward islands. Substantial segements (about 10% and greater) of the world breeding populations of the king and macaroni penguins, and the wandering, grey-headed, yellow-nosed and sooty albatrosses are based at the Prince Edward group. We recommend that Prince Edward Island ( sensu stricto ) should be a wilderness area, and that development at Marion Island should be kept to an absolute minimum.

Seabird consumption and production in the Benguela and Western Agulhas ecosystems

Seabirds were estimated to consume about 430 000 metric tons of food per annum off south-western Africa (15°S to 28°E, from the coast to the 500 m bottom contour) in the 1980s. Of this some 34 per cent was eaten by Cape cormorants, 12 per cent by Cape gannets and 7 per cent by African penguins, species that breed in the region. Among the migrant seabirds, whitechinned petrels accounted for 12 per cent of overall consumption, sooty shearwaters 9 per cent, blackbrowed albatrosses 6 per cent and shy albatrosses 5 per cent. Consumption was higher in the austral winter than in summer because of the greater number of migrant seabirds in the region in winter. Anchovy was the most important prey item, contributing about 31 per cent of all food eaten, followed by pelagic goby (18%), hakes (15%) and zooplankton (8%). Virtually all the hake component of the diet is scavenged from fishing vessels, and of the other main prey items only anchovy is targeted by commercial fishermen. It is estimated that African penguins ...

Body composition and energy metabolism of moulting eudyptid penguins

Abstract 1. 1. Penguins fast during the annual moult. Moulting macaroni penguins, Eudyptes chrysolophus , and rockhopper penguins, E. chrysocome , were analysed for protein, fat and water content. 2. 2. Fat reserves declined by 38g/day and were exhausted after 34 days in macaroni penguins. In rockhopper penguins fat reserves declined by 33g/day and were exhausted after 28 days. 3. 3. Energy consumption of moulting macaroni and rockhopper penguins was 387 kcal/day and 338 kcal/day respectively. 4. 4. Macaroni and rockhopper penguins would need to consume about 16kg and 11kg of crustaceans respectively in order to accumulate sufficient food reserves for moulting.

Review of the rescue, rehabilitation and restoration of oiled seabirds in South Africa, especially African penguins Spheniscus demersus and Cape gannets Morus capensis, 1983–2005

South Africa is a global hotspot for oil pollution. The regional oiled seabird cleaning centre, the South African Foundation for the Conservation of Coastal Birds (SANCCOB), has handled over 50 000 seabirds from its inception in 1968 until 2005. The majority of seabirds oiled in South Africa are African penguins Spheniscus demersus, followed by Cape gannets Morus capensis, both of which are classified as Vulnerable to extinction. On the basis of the proportion of the population that has been affected, the African penguin is considered to have suffered more from oiling than any other seabird species globally. The rehabilitation success (proportion of birds known to have survived for at least one month in the wild) and restoration success (proportion of rehabilitated birds attempting to breed) of de-oiling penguins and gannets are higher than has been reported for any other species. The financial costs of de-oiling African penguins are substantially lower than the costs of de-oiling seabirds in the Northern Hemisphere. De-oiling contaminated birds is thus a valuable conservation intervention for these species, both of which are relatively localised in areas within or close to major shipping routes and ports, where a single spill can threaten a large proportion of the global population. There are, however, long-term effects of oiling on penguins and gannets. De-oiled gannets survive slightly less well than un-oiled birds, but the difference is similar to inter-colony differences in survival. Approximately 27% of rehabilitated African penguins are unable to breed following their release. In addition, oiling has a long-term negative impact on the breeding productivity and cost of reproduction in de-oiled birds. The primary objective should therefore be to prevent or reduce oil spills in the first place. However, future oil spills are inevitable and the authorities need to ensure that they have plans in place and the required capacity to respond rapidly to spills when they do occur. One of the ways to reduce the number of penguins becoming oiled during a spill is to evacuate birds from the affected area. The continued capture and cleaning of penguins and gannets that do become oiled is justified on conservation grounds. Thus, de-oiling should be a twin objective to prevention in South Africas oil spill management strategy, and every effort should be made to further improve both of these aspects.

Return to Robben Island of African Penguins that were rehabilitated, relocated or reared in captivity following the Treasure oil spill of 2000

Following an oil spill from the Treasure off the coast of South Africa in June 2000, about 19 000 oiled African Penguins Spheniscus demersus, including 14 825 from Robben Island, were caught for rehabilitation and subsequent release. A further 19 500 penguins that were not oiled — mostly birds in adult plumage, including 7 000 from Robben Island — were relocated some 700km to the east, to prevent them becoming oiled. Additionally, 3 350 orphaned chicks, including 2 643 from Robben Island — were collected for rearing in captivity and release to the wild. Some four years later — by the end of December 2004 — 70% of rehabilitated adults, 40% of relocated birds and 34% of captive-reared chicks had been seen back at Robben Island. Another 7% of birds relocated from Robben Island had been sighted at other localities. Rates of resighting rehabilitated birds were similar at Robben and Dassen Islands, but a greater proportion of relocated birds was seen at Dassen Island, where birds collected for relocation were mostly from breeding areas. The lower proportion of relocated birds seen at Robben Island is thought to result from this intervention causing some pre-breeding birds to move to other colonies. All three conservation interventions are considered to have been successful, but it is premature to assess their relative contributions to the conservation of the species. Three relocated birds tracked by satellite took 15–21 days to return to their home colonies. This rapid return may have resulted from breeding attempts being interrupted. After remaining at their home islands for 4–5 days, two of the tracked birds then left these islands for 19–36 days. We surmise that, after they had searched unsuccessfully for their mates, they abandoned breeding for the year 2000.

CHICK-FEEDING RATES OF MACARONI AND ROCKHOPPER PENGUINS AT MARION ISLAND

Summary Williams, A. J. 1982. Chick-feeding rates of Macaroni and Rockhopper Penguins at Marion Island. Ostrich 53A29-134. The chick-rearing period of both Macaroni Penguins Eudyptes chrysolophus and Rockhopper Penguins E. chrysocome at Marion Island was 70 days. In this period chicks of both species each received approximately 30 meals, each meal representing one parental foraging trip. Female parents made 22 foraging trips, including all trips in the first 30 days after the chick hatched, and male parents made eight trips. The chicks fasted between meals and in both species 50% of fasts lasted 24–48 h and 93% lasted less than 96 h. The duration of fasts changed in the course of chick-rearing but the pattern of fasting was remarkably similar in the two species. Maximum weight increases following a meal were 0,65 kg in Rockhopper and 2.0 kg in Macaroni Penguin chicks. The estimated total amount of food received by individual chicks during the entire chick-rearing period was 15 kg in Rockhopper and 33 kg i...

Fuel wood use in South Africa: Where to in the 21st Century?

(2002). Fuel wood use in South Africa: Where to in the 21st Century? Southern African Forestry Journal: Vol. 196, No. 1, pp. 1-7.

Competition for space: Recolonising seals displace endangered, endemic seabirds off namibia

Abstract South Africa (Cape) fur seals Actocephalus pusillus pusillus recolonised Mercury Island off South West Africa/Namibia in the early 1980s. By 1986, many endemic seabirds, including endangered and scare species, had been displaced from their breeding sites. The seabirds, already stressed because food resources have been depleted by fisheries, appear unable to compete for space against the heavier seals. Guano scraping has led to a loss of potential refuges and, by lessening the availability of nesting material and the attractiveness of nest sites, may also have weakened the inclination of birds to defend territories. As depleted seal populations recover worldwide, competition between pinnipeds and seabirds for breeding space is likely to increase.

Energy and environment in South Africa: charting a course to sustainability

The past decade has witnessed a sea change in the priorities for the energy sector in South Africa – moving from the apartheid era single-minded emphasis on energy security to a broader concern about access to affordable energy, economic efficiency, and environmental sustainability. Transforming an energy economy based on vast, inexpensive supplies of coal, large public investments in synthetic liquid fuels and nuclear power, and highly inequitable access to clean household fuels, however, presents a major challenge. This paper explores the major environmental impacts associated with energy use in South Africa, identifying areas that are clearly not sustainable. We also chart recent moves forward to address these challenges to “sustainable development” in the energy sector, with a focus on the household sector and bulk energy supply. We present a set of key policy recommendations that stress the importance of pressing economic and social development needs, and improving the quality of life of the majority, as the starting point for developing long term sustainability policies for the sector.