Page 174 - Atlas Sea Birds Ver1

2.2.4.5 Breeding sites of seabirds from Vöelsteen to Cape Point

Authors: AB Makhado, BJ Barham, PJ Barham, BM Dyer, M Masotla, L Upfold, and RJM Crawford

Abstract:
Eleven seabird species have bred at 23 localities in South Africa from Vöelsteen to Cape Point, a region that includes Robben Island
and Cape Town. They are: African Penguin (Spheniscus demersus), Great White Pelican (Pelecanus onocrotalus), Cape Cormorant
(Phalacrocorax capensis), Bank Cormorant (P. neglectus), White-breasted Cormorant (P. lucidus), Crowned Cormorant (Microcarbo
coronatus), Kelp Gull (Larus dominicanus), Hartlaub’s Gull (Chroicocephalus hartlaubii), Grey-headed Gull (C. cirrocephalus), Greater
Crested Tern (Thalasseus bergii) and Caspian Tern (Hydroprogne caspia). All 11 species bred at Robben Island. This island was recolo-
nised by African Penguin in 1983. The colony grew to c. 7,800 breeding pairs in 2004 but it then decreased to < 1,000 pairs in 2022,
trends that were mainly driven by food availability despite oil spills affecting many penguins at the island in 1994 and 2000. Great White
Pelican bred at the island in the 1600s but are not known to have done so subsequently. Cape Cormorant nested at the island sporadically
between 1985 and 2004 and then colonised it, with a maximum of 2,166 pairs breeding in 2012. Kelp Gulls colonised Robben Island in
2000. Substantial numbers of Bank and Crowned cormorant, Hartlaub’s Gull and Greater Crested Tern also bred at Robben Island. Bank
Cormorant additionally nested at four groups of rocks in the region and sizeable numbers of Hartlaub’s Gull and Greater Crested Tern
bred in the greater Cape Town region.

Introduction:
Eleven seabird species have bred at 23 localities in South Africa between Vöelsteen and Cape Point, a region that includes Robben
Island and Cape Town but excludes Cape Point. They are: African Penguin (Spheniscus demersus), Great White Pelican (Pelecanus
onocrotalus), Cape Cormorant (Phalacrocorax capensis), Bank Cormorant (P. neglectus), White-breasted Cormorant (P. lucidus), Crowned
Cormorant (Microcarbo coronatus), Kelp Gull (Larus dominicanus), Hartlaub’s Gull (Chroicocephalus hartlaubii), Grey-headed Gull
(C. cirrocephalus), Greater Crested Tern (Thalasseus bergii) and Caspian Tern (Hydroprogne caspia) (Figure 1).

For each locality, records of breeding by the different spe- Gull (Crawford et al. 1982a, 2009, Whittington et al. 2016);
cies were collated for all years having information. When Hartlaub’s Gull (Williams et al. 1990, Crawford and Under-
multiple counts were obtained for a species in a given year, hill 2003); Grey-headed Gull (Brooke et al. 1999, McInnes
the maximum was shown on the relevant table. ‘√’ signifies and Allan 2011); Greater Crested Tern (Cooper et al. 1990,
that breeding occurred at a locality but the numbers were Crawford 2009); and Caspian Tern (Cooper et al. 1992).
not ascertained; ‘?’ that breeding may have taken place. A These observations were updated by unpublished records
short summary of methods used to obtain the estimates of of South Africa’s Department of Forestry, Fisheries and the
numbers breeding is given in the chapter ‘Introduction to Environment (DFFE).
Seabird Breeding Localities’.
All of the 11 seabird species bred at Robben Island Robben Island
but African Penguin, Great White Pelican, Crowned Coordinates: 33.7960 S, 18.3708 E
Cormorant and Caspian Tern were not known to breed Description: Robben Island, 507 ha in extent, is the larg-
elsewhere in the region. From two to four species bred at est island in the Benguela upwelling ecosystem. It is 7 km
six localities and only one species at the other 16 localities. from the nearest mainland and lies west of Cape Town,
Therefore, Robben Island is first considered and then brief from which it may be accessed by ferries which operate
descriptions are given of the other 22 localities, for which between Cape Town harbour and Murray’s Bay harbour at
numbers breeding are collated by species. the island. There is a settlement and power station at the
In 1998, in the region described Robben Island National island. It rises to a height of c. 30 m and has a lighthouse.
Historical Monument and Rietvlei Wetland Reserve were It is well vegetated, with indigenous vegetation similar to
considered globally Important Bird Areas. In addition to its the West Coast Strandveld found on the adjacent mainland
seabirds, Robben Island also held substantial numbers of and exotic tree plantations. Since arrivals of Europeans in
African Black Oystercatcher (Haematopus moquini) and a South Africa in the 17th century, it has been used to exploit
large heronry (Barnes 1998, Underhill et al. 2007). Reitv- seabirds and seals, for agriculture, to quarry slate and lime,
lei Wetland supported an average of 5,500 waterbirds in as a military garrison (there are several war bunkers) and
summer, with numbers rising above 15,000 in good years for detaining lepers, mentally disadvantaged persons and
(Barnes 1998). prisoners (Crawford and Dyer 2000).
Sources of information for species and numbers African Penguins have mostly nested above the ground’s
breeding: The estimates of numbers of seabirds breeding surface under bushes and trees, with only a few excavating
at the 23 localities were from the following sources: Afri- burrows (Sherley et al. 2014b) presumably on account of a
can Penguin (Shelton et al. 1984, Crawford et al. 1995a, hard substrate. Artificial wooden shelters were deployed at
1999b, 2011, 2013a, Sherley et al. 2020); Great White Peli- the island to provide additional protection to breeding birds
can (Brooke 1983); Cape Cormorant (Cooper et al. 1982, from high insolation. Formerly moulting adults congregated
Crawford et al. 2007a, 2016); Bank Cormorant (Cooper on beaches in summer to shed feathers (Crawford and
1981, Crawford et al. 1999a, 2008, 2015); White-breasted Dyer 2000). Most penguins at Robben Island moult in the
Cormorant (Brooke et al. 1982, Crawford et al. 2013b); austral summer (Underhill and Crawford 1999) when tem-
Crowned Cormorant (Crawford et al. 1982b, 2012); Kelp peratures along the beach are cooler than inland. Energy

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