False Bay wildlife - Cape cormorant

Cape cormorant.

Cormorants are common seabirds, found along southern African coasts, of which 3 species are native to South Africa; the Bank cormorant, Cape cormorant and Crowned cormorant.

Cape cormorants have a greenish glossy shine to their black plumage, with an orange-yellow bare patch of skin at the base on their bills, fairly long necks and striking, turquoise eyes. Their nostrils are completely sealed and so breathe through their mouths. Adapted for swimming, these birds have webbing between all four toes and short wings.

Habitat

These birds are found only along coasts of Southern Africa, breeding between Namibia and Port Elizabeth, and visit as far as the Congo and along the Natal coast. They are abundant in numbers along the south-western Cape coast and are found up to 50kms out to sea.

Cape cormorant taking a dive.

Behaviour

Cape cormorants are usually silent birds but do possess a variety of vocalisations, which include a repeated, low-pitched cluck by males when courting females and a hiss that becomes a bark when feeling threatened.

Cormorants are generally social birds, that nest in colonies, gather in flocks and hunt together, and are often seen flying in long lines or V-shaped flocks. They have a flapping style which puts them in the class of medium speed flying birds. During long flights they pull their energy from fat reserves that are stored.

Diet

Being pellet makers, much like some owls, cormorants create pellets out of the bones and scales of fish they eat and proceed to spit them out.

Cape cormorants feed in large flocks of up to thousands of individuals, on shoals of fish such as pilchards, anchovies and sandeels. They take a short leap out of the water’s surface and then dive into the ocean to mid-water levels. Each dive lasts for around half a minute, with two sessions a day lasting 30 minutes each. Their plumage is easily soaked, reducing buoyancy and allowing them to glide more easily through the water. However, the inner feathers are waterproof to provide a layer of insulation in the chilly water.

Cape cormorant in nest. 

Reproduction

Breeding takes place during any time of the year but predominantly between the months of September and February along the coasts of southern Africa. Male Cape cormorants gather together bits of dried seaweed, sticks and floating debris found in the ocean such as plastic and rope. The female then makes a nest with what she was given, measuring about 30 cms across.

The female cormorant then lays a clutch of between one to five chalky white coloured eggs, usually two to three, at intervals of two to three days. Both parents take turns incubating their eggs for 22 to 28 days and bring food to their offspring once hatched.

Did you know?

The southern African population of Cape Cormorants declined from more than a million birds in the early 1970s to about 120 000 pairs in the mid-1980s.