Seasonal pattern of breeding, population trend and conservation status of bank cormorants Phalacrocorax neglectus off south western Africa

Abstract

At Robben and Malgas islands off western South Africa, the main breeding season for bank cormorants Phalacrocorax neglectus normally extends from May to October. At Ichaboe and Mercury islands, off central Namibia, most breeding activity is usually concentrated between November and April. The overall number of breeding pairs of bank cormorants fell from 8672 in 1978–80 to 4888 in 1995–1997. Human disturbance resulted in the loss of four colonies and reduced populations at six others. About 3000 pairs were lost from the Mercury and Ichaboe islands because of displacement of birds from Mercury Island by Cape fur seals Arctocephalus pusillus in the 1980s and a severe reduction in food off central Namibia in the 1990s. Competition with seals for space occurs at several other localities. Using IUCN criteria, the bank cormorant merits classification as `vulnerable'.