Re: African Penguin
Posted: Tue Jul 09, 2019 11:09 am
The one lying on the back is my favourite
Go wild for Wildlife and help to keep our Conservation Areas pure, natural and green.
http://africawild-forum.com/
Distribution and population
Spheniscus demersus is endemic to southern Africa, where it breeds at 28 localities in Namibia and South Africa (Kemper et al. 2007b, Crawford et al. 2013, Kemper 2015). It has been recorded as far north as Gabon and Mozambique (Crawford et al. 2013).
In Namibia, Neglectus Islet and Penguin Island were recolonised in 2001 and 2006 respectively (Kemper et al. 2007a). In the 1980s, the species colonised Stony Point and Boulders Beach on the South African mainland and recolonised Robben Island, all in the southwest of the country (Underhill et al. 2006). A colony formed on the southern mainland at De Hoop in 2003, but disappeared after 2007. The northernmost colony at Lambert’s Bay became extinct in 2006 (Underhill et al. 2006, Crawford et al. 2011).
In 2015, the population for Namibia was estimated at 5,700 to 5,800 pairs (MFMR unpubl. data), the uncertainty in the estimate arising from a few islands that had not been counted for several years (J. Kemper pers. comm.). The most important colonies were Mercury Island: 2,646 pairs, Ichaboe Island: 488 pairs, Halifax Island: 1,092 pairs and Possession Island: 1,205 pairs (MFMR unpubl. data).
In 2019, c.13,300 pairs bred in South Africa: St Croix Island: 3,638 pairs, Bird Island (Algoa Bay): 2,378 pairs, Dassen Island: 1,912 pairs, Stony Point: 1,705 pairs , Robben Island: 1,190 pairs, Dyer Island: 1,071 pairs, Simonstown: 932 pairs (Department of Environmental Affairs, SANParks and CapeNature unpubl. data). Just seven colonies now support 97% of the South African population. Recent declines at South African colonies are coincident with changes in the abundance and availability of forage fish and an eastward movement of spawning forage fish (Crawford et al. 2011, Waller 2011, Sherley et al. 2014a).
Ecology
Behaviour Adults are largely resident, but some movements occur in response to prey movements (Hockey et al. 2005). Adults generally remain within 400 km of their breeding locality, although they have been recorded up to 900 km away (Hockey et al. 2005, Roberts 2015). They breed and moult on land before taking to the sea, where they can remain for up to four months (Crawford et al. 2013, Roberts 2015). On gaining independence, juveniles disperse up to 2,000 km from their natal colonies, with those from the east heading west, and those from the west and south moving north (Sherley et al. 2013a, Sherley et al. 2017). Most birds later return to their natal colony to moult and breed (Randall et al. 1987, Sherley et al. 2014a), although the growth of some colonies has been attributed to the immigration of first-time breeders tracking food availability (Crawford 1998, Crawford et al. 2013). Adults nest colonially, but may also nest in isolation. At sea they forage singly, in pairs or sometimes co-operatively in small groups of up to 150 individuals (Wilson et al. 1986, Kemper et al. 2007b, Ryan et al. 2012, McInnes et al. 2019). African Penguins forage more successfully in groups when feeding on schooling fish (McInnes et al. 2017). The species breeds year round with peak months varying locally (Crawford et al. 2013). In the north-western part of the range, peak laying occurs during the months of November to January; in the south-west it occurs between May and July, and in the east between April and June (Crawford et al. 2013). The average age at first breeding is thought to be 4-6 years (Whittington et al. 2005).
Habitat This species is marine and usually found within 40 km of the coast (Wilson et al. 1988, Petersen et al. 2006, Pichegru et al. 2009, 2012), coming ashore on islands or at non-contiguous areas of the mainland coast to breed, moult and rest (Hockey et al. 2005). Breeding: Breeding habitats range from flat, sandy islands with varying degrees of vegetation cover, to steep rocky islands with little vegetation (Hockey et al. 2005). African Penguins are sometimes found close to the summit of islands and may move over a kilometre inland in search of breeding sites (Hockey 2001). They usually feed within 20 km of the colony when breeding, although at some colonies the distance is greater (Pichegru et al. 2009, Waller 2011, Ludynia et al. 2012, Pichegru et al. 2012). Non-breeding: At sea, their distribution is mainly restricted to the greater Benguela Current region (Williams 1995). Juveniles have been observed to travel ~600 km from their natal colonies (Sherley et al. 2017), while immatures up to 700 km with an average of ~370 km from the colony (Grigg and Sherley 2019). Pre- and post moulting adults have been observed up to 550 km from their colonies (de Blocq et al. 2019).
Diet Adults feed predominantly on pelagic schooling fish of 50-120 mm length, with important prey including sardine Sardinops sagax, anchovy Engraulis capensis, bearded goby Sufflogobius bibarbatus and round herring Etrumeus whiteheadi (Crawford et al. 1985, Ludynia et al. 2010, Crawford et al. 2011). In some localities, cephalopods represent an important food source (Crawford et al. 1985, Connan et al. 2016). Juveniles are thought to prey on fish larvae (Wilson 1985).
Breeding site In the past, nests were usually built in burrows dug in guano or sand (Frost et al. 1976a, Shelton et al. 1984). Today, with the lack of guano at most colonies, nesting in open areas has become increasingly common (Kemper et al. 2007b, Sherley et al. 2012, Pichegru 2013). At some sites, artificial nest-burrows made from pipes and boxes sunken into the ground, and shelters shaped from dry vegetation have been regularly used by the species (Kemper et al. 2007a, Sherley et al. 2012, Pichegru 2013).