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The White Breasted Cormorant

Updated: Dec 2, 2020

As the SAPREC team dealt with one of these beautiful water birds, we thought it a good idea to share some more information regarding them. They are known more as water birds than seabirds, because they are rarely seen


out at sea. They prefer the shorelines, sand and rocks of a variety of marine and fresh water habitats. These birds are found worldwide and frequently occur along the Southern African coastline as well as in the eastern and southern interior of South Africa. They are therefore referred to as localized


residents. They may occur singly or in groups on coastal rocks, islands and estuaries or at inland wetlands, mangrove swamps, large dams and rivers. Approximately half of the entire White Breasted Cormorant population is non-marine, as they do not live anywhere close to the sea. The bird is the largest African Cormorant and the adult has a glossy, dark-brown plumage, except for the white patch on the throat, thigh, cheeks and breast. Immature birds have an entire white belly and are considerably smaller. The adults have greenish – turquoise eyes with a pale grey bill and a darker yellow skin at the base of the bill. Their legs and large webbed feet are blackish in colour. The size of the bird: Length = 80 – 100 cm Wingspan = 120 – 150 cm Weight: Male = + 3100 grams / Females = + 1800 grams They are normally very quiet birds but within a colony, they make squeaks, growls, hisses and grunts. They breed in colonies, laying 3 – 4 eggs in large stick nests in trees, bushes, reeds, cliffs or on the ground on islands. At times, they are found with herons, ibises, egrets, darters or other cormorants. The male selects and defends a nest-site and will later try to attract a female to the site with wing waving and displaying the white thigh patches, as the wings are moving. The male will collect the nesting material but the female builds the nest with sticks, twigs, feathers and the occasional bits of debris found lying around. The nest is soon covered in guano and may often be reused in the following years. Once the pair has been formed, the bond will be strengthened by gurgling with the head held upwards, mutual preening and neck entwining. These birds are mostly sedentary in their range and only move due to water level changes or disturbances. The breeding season peaks between September and December in the Western Cape region of South Africa and in other areas between January and July. Both adults are actively involved during the incubation time of 28 – 30 days and once the chicks have hatched both the parents, feed them by regurgitated food. Human disturbance poses a serious threat at breeding sites and these cormorants are more susceptible to disturbance than many other marine cormorants. They leave their nests for extended periods if they are disturbed which means that the eggs or chicks are exposed and preyed upon. Other threats that these birds face are Avian Cholera, discarded fishing line and hooks, feral dogs, oil pollution, plastic pollution and the deliberate killing of the birds by humans. The White Breasted Cormorant feeds mainly on fish and therefore dives frequently in order to obtain its meal. Occasionally they also feed on crustaceans, mollusks and amphibians. It swims and dives to a depth of about ten meters and will pursue its prey by swimming after it underwater. They usually grab the prey in their bills and swallow it immediately, but this depends on the size of the prey. If the prey is too large, they will take it to the shore where it will be consumed. These birds are often seen perched with their wings spread open on branches, rocks or exposed perches. They are powerful in flight and are able to fly low over the water with the head and neck outstretched. The White-Breasted Cormorant is listed as Endangered in some parts but are not globally threatened. Photographs provided by René Hodges.


 
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