Page 208 - Atlas Sea Birds Ver1

2.2.4.8 Coastal breeding sites of seabirds between Cape Agulhas
and Mossel Bay

Authors: BM Dyer, RJM Crawford, C Hagen, PGH Kotze, K Spncer, L Upfold, JL Visagie, and AB Makhado

Abstract:
Nine species of seabird have bred at 23 localities between Cape Agulhas and Mossel Bay, of which all except Seal Island at Mossel Bay
are mainland sites. The species that bred in the region are African Penguin (Spheniscus demersus), Cape Cormorant (Phalacrocorax
capensis), White-breasted Cormorant (P. lucidus), Crowned Cormorant (Microcarbo coronatus), Kelp Gull (Larus dominicanus), Grey-
headed Gull (Chroicocephalus cirrocephalus), Greater Crested Tern (Thalasseus bergii), Caspian Tern (Hydroprogne caspia), and
Damara Tern (Sternula balaenarum). The sites are briefly described and information on numbers breeding is collated.
Introduction:
Nine species of seabird have bred at 23 localities in South Africa’s Western Cape between Cape Agulhas, at the southern tip of Africa,
and Mossel Bay (Figure 1). The species that bred in the region were African Penguin (Spheniscus demersus), Cape Cormorant (Phala-
crocorax capensis), White-breasted Cormorant (P. lucidus), Crowned Cormorant (Microcarbo coronatus), Kelp Gull (Larus dominicanus),
Grey-headed Gull (Chroicocephalus cirrocephalus), Greater Crested Tern (Thalasseus bergii), Caspian Tern (Hydroprogne caspia), and
Damara Tern (Sternula balaenarum).
Cape Agulhas is often thought of as the border between the Indian Ocean to the east and the Atlantic Ocean to the west. However,
the Benguela upwelling system (BUS) off southwestern Africa is usually considered to extend eastward from southern Africa’s Atlantic
seaboard around Cape Agulhas to about Woody Cape in South Africa’s Eastern Cape Province (Makhado et al. 2021). The Bank Cormo-
rant (P. neglectus), which is endemic to the BUS, has only been recorded breeding west of Cape Agulhas (Cooper 1981, Crawford et al.
1999). Similarly, in the 20th century Crowned Cormorant and Hartlaub’s Gull (C. hartlaubii), also endemic to BUS, only bred west of Cape
Agulhas (Crawford et al. 1982b, Williams et al. 1990), although in the 21st century small numbers of both species extended their breeding
ranges to the east of Cape Agulhas (Whittington 2004, Crawford et al. 2008, 2009). Historically, three other BUS endemics, African
Penguin, Cape Gannet (Morus capensis), and Cape Cormorant, bred east and west of Cape Agulhas but with a preponderance in the
west (Cooper et al. 1982, Crawford et al. 1983, Shelton et al. 1984). In South Africa, there was a recent eastward shift in the breeding
distributions of these species that matched similar shifts in the distributions of their prey, and the largest Cape Gannet colony is now in
Algoa Bay (Crawford et al. 2015).
The 23 breeding sites are briefly described below. For each site, records of breeding by the different species were collated for all years
having information. For years having multiple counts, the highest count was shown; ‘√’ signifies that breeding occurred at a locality but
the numbers were not ascertained. A short summary of methods used to obtain the estimates of numbers breeding is given in the chapter
‘Introduction to Seabird Breeding Localities’.
In 1998, in the coastal region considered, the Heuningnes River and Estuary System and De Hoop Nature Reserve were identified
as Globally Important Bird Areas (Barnes 1998).

Sources of information: Conservation status: Not protected.
The estimates of numbers of seabirds breeding at the Species breeding and numbers breeding: Grey-headed Gull
23 localities were from the following sources: African
Penguin (Shelton et al. 1984, Underhill et al. 2006); Cape Year No. of pairs Source
Cormo- rant (Cooper et al. 1982, Crawford et al. 2016); 1959 2 Brooke et al. (1999)
White- breasted Cormorant (Brooke et al. 1982, Crawford 2018 0 DFFE (unpubl.)
et al. 2013); Crowned Cormorant (Crawford et al. 1982b,
2012); Kelp Gull (Crawford et al. 1982a, Whittington et al. Struis Bay beach to the mouth of the Heuningnes River
2016); Hartlaub’s Gull (Williams et al. 1990); Grey-headed at De Mond
Gull (Brooke et al. 1999); Greater Crested Tern (Rand Coordinates: Struis Bay beach 34.7685 S; 22.0467 E.
1963, Cooper et al. 1990); Caspian Tern (Cooper et al. Heuningnes River Mouth 34.7134 S; 20.122 E
1992); and Damara Tern (Williams et al. 2004, Braby 2011). Description: A stretch of beach that runs from the Struis
These observations were updated by unpublished records Bay beach car park to about 3.5 km east of the Heuningnes
of South Africa’s Department of Forestry, Fisheries and River Mouth and the Heuningnes River Estuary, which is
the Environment (DFFE). the southernmost estuary in Africa. It is formed where
the river reaches the sea through a double ridge of sand
Near Bredasdorp dunes. The estuary comprises an extensive bay with sand,
Coordinates: 34.53 S; 20.03 E mudflats, and tidal saltmarsh (Barnes 1998). The estuary
Description: Grey-headed Gulls bred at a small island in a and beach east of the mouth and to about 5 km west of it lie
vlei on a farm in the Bredasdorp area in September 1959. within De Mond Nature Reserve (DMNR). In the summers
Their nests were depressions on dry ground in grass about of 1997–2002, colonies of White-breasted Cormorant and
30 cm high that were lined sparingly with grass (MacLeod Caspian Tern bred between dunes east of the Heuningnes
et al. 1960). The exact locality is uncertain. On a search Estuary. In the summer of 2002/03 the colonies shifted
around wetlands in the region in November 2018 no sign of west of the estuary to an area where disturbance by off-
breeding by Grey-headed Gull was noticed (DFFE unpubl.) road vehicles (ORVs) had previously been heavy but had
but further searches should be conducted. been banned from December 2001. The cormorants bred

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