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South Africa

Malgas Island

René Navarro
Animal Demography Unit

  Malgas Island carpeted by breeding Cape gannets
Photo René Navarro
Malgas Island carpeted by breeding Cape gannets

Malgas Island (33°03'S, 17°55'E), lies about 800 m from the mainland, it is located at the northern entrance of Saldanha Bay in the Benguela upwelling system.It is a small island, about 8.3 ha, almost rectangular and fairly flat, with the highest point raising about 9 m above sea level. Parts of the island consist of smooth rock and big boulders, though there are patches of shallow soil, guano, sand and shell fragments.

Most of the central areas of the island are occupied by nesting Cape Gannets, whereas other nesting seabirds are mostly confined to the periphery. One exception is the Kelp Gull Larus dominicanus that have managed to establish themselves in the very centre of the island, although in low numbers. The few rocky outcrops in the midst of the gannets' nesting ground are used both by Crowned and Cape Cormorants.

The breeding seabirds include Bank Cormorants Phalacrocorax neglectus, Cape Cormorants P. capensis and Crowned Cormorants P. coronatus, Kelp Gulls and Hartlaub's Gulls L. hartlaubii, and African Penguins Spheniscus demersus.

The scarce vegetation consists mostly of low herbs that grow during winter but there is almost no vegetation during summer. There are no terrestrial mammals on Malgas Island. The table below lists the biodiversity of the island.

The paucity of the flora and fauna found at Malgas Island can be traced to its history. Malgas, as well as all the other coastal islands of southern Africa are part of the continental plate, and during the Pleistocene glaciations (12 000 years ago) were part of the mainland. About 2000 years ago the sea level was at least 3 m higher than at present, during this time most islands, including Malgas, were either completely covered by water (appearing only at low tide) or were frequently awash by high seas during storms at spring tide. Clearly, most terrestrial flora and fauna was completely eradicated from the islands. Other factor that has a negative effect on the island's biodiversity are the seabirds themselves. The high density of gannets literally covers everything in guano, which, in spite of its famous fertilizing qualities, is in itself quite inert.

Crowned cormorants
Photo René Navarro
Crowned cormorant create these turret nest structures by adding new nests on top of old ones. This species breeds all year round at Malgas Island
 
African Black Oystercatcher
Photo René Navarro
Crowned cormorant create these turret nest structures by adding new nests on top of old ones. This species breeds all year round at Malgas Island

Human impact on the nesting areas includes removal of the guano cap in 1845, construction of low retaining walls, paths for guano collectors and several buildings at the eastern side of the island, where the landing jetty is also found.

See also the Malgas' photo gallery.

Aerial view of Malgas
Photo Marine and Coastal Management
Bird's eye view of Malgas Island.
Enlarge.

Flora and fauna recorded at Malgas Island. The list of birds is rectricted to those recorded breeding (source of data: Brooke RK & Crowe TM 1982. S. Afr. J. Zool. 17: 49-58, and personal observations.

Class [Order:] Family Species
Aves Spheniscidae African penguin, Spheniscus demersus
  Sulidae Cape gannet, Morus capensis
  Phalacrocoracidae Bank cormorant, Phalacrocorax neglectus
    Crowned cormorant, P. coronatus
    Cape cormorant, P. Capensis
  Plataleidae Sacred ibis, Threskiornis aethiopicus
  Anatidae Egyptian goose, Alopochen aegyptiacus
  Haematopodidae African black oystercatcher, Haematopus moquini
  Charadriidae Blacksmith plover, Vanellus armatus
  Laridae Kelp gull, Larus dominicanus
    Hartlaub's gull, L. harlaubii
  Columbidae Rock pigeon, Columba guinea
  Motacillidae Cape wagtail, Motacilla capensis
  Sturnidae European starling, Sturnus vulgaris
  Passeridae House aparrow, Passer domesticus
Reptilia Gekkonidae Afrogecko porphyrens (photo)
Arachnida Acaridae Ornithodoros capensis
    Dictynidae sp.
  Eresidae Eresus sp.
  Sparassidae Two undetermined species
  Lycosidae One undetermined species
  Pidauridae One undetermined species
Crustacea Isopoda Porcellio scaber
Insecta Diptera: Coelopidae Dipteron sp.
  Diptera: Calliphoridae One undetermined species
  Diptera: Muscidae Musca domestica
  Coleoptera: Staphylinidae Xantholinus sp.
  Coleptera: Dermestidae Dermested maculatus
Plants
Angiospermae Chenopodiacea Atriplex semibaccata
    A. patula
    Chenopodium murale
  Mesembryanthemaceae Mesembryanthemum crystallinum
    Prenia pallens
  Malvaceae Lavatera arborea
    Malva parviflora
  Myoporaceae Myoporun serratum
  Asteraceae Senecio vulgaris

Aerial view of Malgas Island in winter 1979, this picture was used to count the number of nesting pairs on the island. Look out for the white specks against the darkest areas near the top-centre of the island (see enlarged area below). At present the extent of the areas occupied by Cape Gannets is much larger. In fact, gannets now carpet almost the entire island, some even nesting on the flat rocks!
The builings and jetty are on the southern side, looking towards Saldanha Bay.

Malgas Island
Photo © Marine and Coastal Management
Malgas Island
Malgas Island. Close-up on a section of the gannet colony
Photo © Marine and Coastal Management
Malgas Island. Close-up on a section of the gannet colony

Malgas Island - Photo Gallery

Photos by René NavarroRené Navarro
Animal Demography Unit, Department of Zoology, University of Cape Town

Afrogeko prophyrens
Afrogeko prophyrens
Malgas Is.: Rock landscape I
Malgas Is.: Rock landscape I
Malgas Is.: Rock landscape II
Malgas Is.: Rock landscape II
African penguin
African penguin with baby-blue chick
Sacred ibis
Sacred Ibis roosting at Malgas
Gannet circling the island
Cape Gannet circling the island
Tanker
The ever present menace: an oil-carrier enters Saldanha Bay
Rocks and Jetty
Rocks & Jetty
Welcome to Malgas
Welcome to Malgas! This view greets visitors
Cape Cormorants
Cape Cormorants
Cape Gannet landing I
Cape Gannet landing I
Cape Gannet landing II
Cape Gannet landing II
Bank Cormorant
Bank Cormorant
Turnstones - Arenaria interpres
Turnstones - Arenaria interpres