Cape Gannet

The Cape Gannet is a large, striking seabird of the southern African coast, closely related to the Northern and Australasian Gannets. Adults are gleaming white with jet-black wingtips and a narrow black line down the throat, giving them a sharply tailored look in flight. The head and nape are washed with a soft golden-yellow that fades gradually into the white body, and the pale blue-grey bill is long, straight, and dagger-like.

Cape Gannets breed in some of the most spectacular seabird colonies in the world, packed shoulder to shoulder on a small number of islands, where the constant activity, noise, and guano-whitened rock make for an unforgettable spectacle.

Key field marks

• Large white body with black wingtips visible in flight
• Golden-buff wash on the crown and nape
• Long, straight, pale bill with a thin black line bordering the gular area
• Pointed tail, often held closed and slightly wedge-shaped

Similar species

• Australasian Gannet is very similar but has black central tail feathers, a feature Cape Gannet lacks.
• Northern Gannet is larger overall and does not overlap in range with Cape Gannet.
• Juveniles of all gannet species are mottled brown and take several years to reach full adult plumage, making them harder to separate; range is the best clue for South African birds.

Cape Gannets nest almost exclusively on a handful of islands off the coasts of South Africa and Namibia, including Malgas Island, Bird Island, and Lambert's Bay. Outside the breeding season, birds disperse widely along the Benguela and Agulhas current systems, foraging over cold, productive offshore waters rich in shoaling fish.

Some individuals move considerable distances along the African coastline after breeding, occasionally reaching as far as West Africa, but the species remains centered on the southern African marine ecosystem year-round.

Behavior

Cape Gannets are spectacular plunge-divers, folding their wings back and dropping from heights of 10-30 meters to spear into shoals of sardines and anchovies, sometimes in large cooperative flocks that create a dramatic curtain of birds hitting the water together.

Voice

At breeding colonies they give loud, harsh, repeated "arrah-arrah" calls used in nest-site defense and pair greeting displays; at sea they are largely silent.

Feeding

They rely heavily on small pelagic fish, and breeding success is closely tied to the availability of sardine and anchovy stocks.

Nesting and breeding

Cape Gannets nest in tightly packed colonies, laying a single egg in a simple mound nest of guano and debris; both parents share incubation and chick-rearing duties over several months.