Page 351 - Atlas Sea Birds Ver1

propensity of the species to move between breeding areas, may be present in birds but only become symptomatic
consideration should also be given to including sites where under conditions of stress, such as food scarcity (Crawford
large numbers of Cape Cormorants formerly bred as sites et al. 1992a).
of importance for the species. Cape Cormorants are sensitive to human disturbance
at breeding sites and, if displaced from nests, may lose
Conservation issues eggs and chicks to avian predators, such as Kelp Gulls
(Larus domicanus) (Jarvis and Cram 1971, Cooper et al.
A decreased availability of high-energy fish prey led to 1982, Kemper and Simmons 2015). Great White Pelicans
decreases in numbers of Cape Cormorants breeding in (Pelecanus onocrotalus) have fed on Cape Cormorant
Namibia and South Africa (Crawford 2007, Crawford et al. adults and chicks (de Ponte Machado 2010, Mwema
2007, 2014, 2016, 2018, 2019, Masiko et al. 2021). When et al. 2010). Cape Fur Seals (Arctocephalus pusillus
pusillus) have killed large numbers of fledglings around
food is scarce Cape Cormorants may suffer high mortality, islands (Voorbergen et al. 2012, Makhado et al. 2013).
have greatly reduced breeding success, skip or abandon Cape Cormorants are vulnerable to oil spills (Crawford et
breeding, and defer their age at first breeding (Berry 1976, al. 2000). Rehabilitation success of oiled birds was low
Crawford et al. 1980, 1992b, 2001, Duffy et al. 1984, (Crawford 2005). In South Africa, Cape Cormorants often
Crawford and Dyer 1995). Diseases such as avian cholera move east in winter after breeding (Crawford 2005). At that
and avian influenza have killed substantial numbers of birds time large numbers often feed in estuaries in the east of
(Crawford et al. 1992a, Williams and Ward 2002, Waller the Western Cape and in the Eastern Cape (Crawford et
and Underhill 2007, Khomenko et al. 2018). Avian cholera al. 2016).

A Cape Cormorant at its nest (photo BM Dyer)

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