Africa Wild Bird Book

[Dewi]

056. Cape Cormorant Phalacrocorax capensis (Trekduiker)
Order: Suliformes. Family: Phalacrocoracidae

Cape Cormorant.jpg (61.54 KiB) Viewed 1053 times

Description
Though looking like nondescript black birds from a distance, at close range the black plumage of Cape Cormorants can be seen to have a blueish sheen, which is iridescent in breeding adults. Head without crest. The eyes are turquoise in adults, with blue beads on the eyelids, and grey in juveniles. The gape at the base of the bill of adults is yellow-orange.
Juvenile Cape Cormorants differ from adults in their dark brown plumage and pale underparts.

Distribution
Cape Cormorants are endemic to southern Africa, where they are abundant on the west coast but less common on the east coast of southern Africa. They breed between Ilha dos Tigres, Angola, and Seal Island in Algoa Bay, South Africa. Non-breeding birds range as far north as Lobito, Angola, and Inhaca Island, Mozambique, and vagrants have been recorded from Gabon. On the east coast they follow shoals of sardine Sardinops sagax that migrate along the KwaZulu-Natal coast (South Africa), occasionally irrupting into southern Mozambique.



Habitat
Coasts, marinas, harbours and estuaries.

Diet
They generally feed within 10-15 km of the shoreline, preying on Pelagic Goby Sufflogobius bibarbatus, Cape Anchovy Engraulis capensis, Pilchard Sardinops occelatus and Cape Horse Mackerel Trachurus trachurus.

Breeding
Breeding colonies are equally immense as the feeding flocks. Breeding may take place at any time of the year, but egg-laying primarily takes place between September and February. The male gathers dried seaweed, sticks, and floating ocean debris, such as plastic, netting and rope, from which the female constructs a nest, measuring about 30 centimetres across. Into this flimsy structure is laid a clutch of one to five chalky white eggs (most commonly two to three), which are laid at intervals of two to three days. Both the male and female share the task of incubating the eggs for 22 to 28 days, and when the young hatch, both bring food to the young. Parental care even extends to sheltering the newly hatched young from the sun, with adults observed standing with their wings outstretched with their backs to the sun. After five to six weeks, the young leave the nest to form small crèches of up to ten birds, and by nine weeks the young can fly. This fledgling population is very vulnerable to predators; Cape fur seals prey heavily on seabirds in southern Africa, and Cape cormorants are particularly susceptible to predation when they land on the waters surrounding breeding islands.

Spoor


Status
Common to abundant endemic resident. Near-threatened, as its population has decreased from 277 000 pairs in 1977-1981 to just 72 000 pairs in 1996. This may be part of a natural process, linked to the large natural variations in the population of Anchovies (Engraulis encrasicolus). Human interference also has a negative effect, often causing nest desertion and subsequent predation of chicks and eggs.

[Dewi]

056. Cape Cormorant Phalacrocorax capensis

© Dewi

© Toko
Hondeklip Bay

© nan
Lamberts Bay

Links:
Species text Sabap1
Sabap2
Cruising for cormorants along the Atlantic Ocean coastline

[Toko]

The darters or snakebirds are mainly tropical waterbirds in the family Anhingidae having a single genus Anhinga. There are four living species, three of which are very common and widespread while the fourth is rarer and classified as near-threatened by the IUCN. The term "snakebird" is usually used without any additions to signify whichever of the completely allopatric species occurs in any one region. It refers to their long thin neck, which has a snake-like appearance when they swim with their bodies submerged, or when mated pairs twist it during their bonding displays. "Darter" is used with a geographical term when referring to particular species. It alludes to their manner of procuring food, as they impale fishes with their thin, pointed beak.
Anhingidae are large birds with sexually dimorphic plumage. They measure about 80 to 100 cm in length, with a wingspan around 120 cm. The males have black and dark brown plumage, a short erectile crest on the nape and a larger bill than the female. The females have a much paler plumage, especially on the neck and underparts, and are a bit larger overall. Both have grey stippling on long scapulars and upper wing coverts. The sharply pointed bill has serrated edges, a desmognathous palate and no external nostrils. The darters have completely webbed feet, and their legs are short and set far back on the body.
There is no eclipse plumage, but the bare parts vary in color around the year. During breeding, however, their small gular sac changes from pink or yellow to black, and the bare facial skin, otherwise yellow or yellow-green, turns turquoise. The iris changes in color between yellow, red or brown seasonally.
Darters are mostly tropical in distribution, ranging into subtropical and barely into warm temperate regions. They typically inhabit fresh water lakes, rivers, marshes, swamps, and are less often found along the seashore in brackish estuaries, bays, lagoons and mangrove.
Darters feed mainly on mid-sized fish. These birds are foot-propelled divers that quietly stalk and ambush their prey; then they use their sharply pointed bill to impale the food animal. They do not dive deep but make use of their low buoyancy made possible by wettable plumage, small air sacs and denser bones. On the underside of the cervical vertebrae 5-7 is a keel, which allows for muscles to attach to form a hinge-like mechanism that can project the neck, head and bill forward like a throwing spear. After they have stabbed the prey, they return to the surface where they toss their food into the air and catch it again, so that they can swallow it head-first. Like cormorants, they have a vestigial preen gland and their plumage gets wet during diving. To dry their feathers after diving, darters move to a safe location and spread their wings.
They usually breed in colonies, occasionally mixed with cormorants or herons. The darters pair bond monogamously at least for a breeding season. There are many different types of displays used for mating.

[Toko]

There is only one species that occurs in southern Africa:

Family Anhingidae (Darters)
Anhinga rufa African Darter 060

[Flutterby]

060. African Darter Anhinga rufa (Afrikaanse Slanghalsvoel)
ORDER SULIFORMES. Family: Anhingidae

African Darter.jpg (65.68 KiB) Viewed 1055 times

Description
Has a long neck, slender head and long, pointed dagger-like (not hooked) straight pointed bill. When swimming it sometimes totally submerges its body, leaving only its long neck and head showing. It has long black tail, held fanned when resting. Legs and webbed feet are brown.
Adult male breeding: Upper parts blackish brown; scapulars elongate, tertials and lesser and median upper wing coverts with prominent white shafts. Scapulars and outer webs of central rectrices with transverse corrugations. Greater coverts rich brown, with black margins, forming rufous panel on folded wing. Flight feathers and underwing black. White stripe extends from below eye across cheek and down neck, with narrow black lower border on neck. Chin cream, grading into chestnut down throat to upper breast. Lower breast and belly blackish brown. Bill pale yellow-horn or greenish horn. Eyes golden yellow, sometimes brown or red. Bare pale green facial skin forms eye ring. Gular pouch cream or pale green, but black in courtship period. Legs and feet pale brown, darker in courtship period.
Females and non-breeding males are pale brown on the face and throat. Female has brown crown and upper neck. She has less distinct white stripe on the neck sides.
Juveniles have a buffy neck, more streaking on the head and neck, and lack streaking on the back. Nestlings are white (cormorants are black).
Similar species: This species can be differentiated from cormorants by their pointed bills. (Cormorants have strong hook on end of beak.) The African Darter lacks red bill and legs of the adult African Finfoot.

Distribution
Patches across sub-Saharan Africa; in southern Africa it is fairly common in Zimbabwe, northern and eastern Botswana, South Africa and patches of Namibia and Mozambique.

Habitat
Still and slow-moving freshwater, including swamps and marshes.

Diet
Mainly fish, also frogs. It uses its webbed feet to dive underwater before stabbing the fish with its bill.

Breeding
Monogamous and colonial, joining other water birds such as White-breasted and Reed Cormorants, African Spoonbill and Herons in colonies of 10-50 pairs. The nest is built by both sexes in just a day or so, consisting of an untidy platform of sticks or dead reeds, with a shallow cup in the centre which is lined with grass. It is typically placed in a tree fork over water, or alternatively in a reedbed. Egg-laying season is year-round, peaking from August-October in the Western Cape but from October-December elsewhere. It lays 2-7 greenish or bluish eggs, which are incubated by both sexes for roughly 22 days. The chicks are fed by both parents, leaving the nest after about 5-6 weeks, although they may drop into the water earlier if disturbed; they take their first flight at roughly seven weeks old.

Call
Usually silent away from nest. Occasional shrieks of chack chack chack notes.
Listen to Bird Call.

Status
Fairly common resident, sedentary. Local movements linked to water levels and food availability.

[Flutterby]

060. African Darter Anhinga rufa


Perches with outspread wings.

© BluTuna

© BluTuna

© JustN@ture

© Michele Nel
The Darter is able to retract and extend its necks and maintain the neck retracted during flight - unlike most other long-necked birds.

© Dewi
Immature

© steamtrainfan
Swims with body submerged, only head and neck showing.


The African darter differs from most other waterbirds in that its feathers do not contain any oil and do not, therefore, repel water. This means that the darter is less buoyant and it is able to dive more easily. It does mean, though, that the feathers can become waterlogged during diving and in order to enable the bird to fly and also to assist in restoring the feathers insulating properties, the feathers must be dried. For this reason the African darter is often seen perched on a convenient rock or tree with its wings spread wide to the sun and the wind.

Links:
Species text Sabap1
Oiseaux net
Ryan, P. 2013. Underwater heron: African Darter. African Birdlife 1(5):54-60.

[Toko]

ORDER ACCIPITRIFORMES (Diurnal birds of prey, excl. falcons)

The Accipitriformes is an order that has been proposed to include most of the diurnal birds of prey: buzzards, eagles, harriers, hawks, kites, Old World vultures and some others, about 225 species in all. For a long time, the majority view has been to include them with the falcons in the Falconiformes, but some authorities have recognized a separate Accipitriformes. A DNA study has indicated that falcons are not closely related to the Accipitriformes, being instead related to parrots and passerines. (Falcons unlike other birds of prey never build nests of their own. They simply uses old bird nests instead, or lay their eggs at a cliff or construction without preparation. Falcons also have a jack in their beak, which is absent in other birds of prey.)
Accipitriformes are known from the Middle Eocene and typically have a short, sharply hooked beak with a fleshy cere (soft mass) on the proximodorsal surface, housing the nostrils. Their wings are long and fairly broad, suitable for soaring flight, with the outer 4–6 primaries emarginated.
Accipitriformes have strong legs and feet with raptorial claws (curved) and an opposable hind claw. The legs are generally short with powerful feet, except for in the stately long-legged Secretarybird. Almost all Accipitriformes are carnivorous, hunting by sight during the day or at twilight. Diets range from small insects to large vertebrates, carrion, and oily fruits. They are exceptionally long-lived, and most have low reproductive rates.
Most species breed in trees, although some breed on cliff ledges or in tree cavities. Clutches range from three to five eggs in small species to one to two in large species. The semiprecocial young hatch covered with down and their eyes open. The young have a long, very fast-growing fledgling stage, followed by 3–8 weeks of nest care after first flight, and 1 to 3 years as sexually immature adults. After they leave the nest, young birds of prey depend on their parents for food for up to several months until they develop hunting skills. The sexes have conspicuously different sizes and sometimes a female is more than twice as heavy as her mate. This sexual dimorphism is sometimes most extreme in specialized bird-eaters, such as the Accipiter hawks. Monogamy is the general rule, although an alternative mate is often selected if one dies.
The Accipitriformes are among the most diverse orders in size, from the small sparrowhawks to the biggest Old World vultures.
This order has a worldwide ditribution, found on all continents ecxept the Artic and Antartic region It is one of the most recognizable and familiar groups.

[Toko]

In Southern Africa, there are three families in the ORDER ACCIPITRIFORMES
Family Sagittariidae (1 species only: Secretarybird)
Family Pandionidae (1 species only: Osprey)
Family Accipitridae (Kites, Hawks and Eagles)

[Lisbeth]

118. Secretarybird Sagittarius serpentarius (Sekretarisvoël)
ORDER ACCIPITRIFORMES. Family Sagittariidae

The Secretarybird or Secretary Bird is a very large, mostly terrestrial bird of prey. Although a member of the order Accipitriformes, which also includes many other diurnal raptors such as kites, buzzards, vultures, and harriers, it is given its own family, Sagittariidae.

Secretarybird Sagittarius serpentarius.jpg (56.02 KiB) Viewed 1103 times

Description
The Secretarybird is instantly recognizable as having an eagle-like body on crane like legs. The bird gets its name from its crest of long feathers black feathers behind the head that look like the quill pens. It is basically dove-grey in color, with black on the wings, thighs and elongated central tail feathers. It has an eagle like head with a short, down-curved bill is backed by an area of bare, red and orange skin. The tail has two elongated central feathers that extend beyond the feet during flight.
Sexes exhibit very little sexual dimorphism, although the larger male has longer head plumes and tail feathers.
Juveniles have yellow faces. Plumage browner, and with shorter tail.

Distribution
All over Sub-Saharan Africa: widespread from Senegal and southern Mauritania east to Ethiopia and western Somalia and south to South Africa.



Habitat
Savanna and open grasssland with scattered trees from coastal regions to high altitudes.

Movements and migrations
Resident and nomadic, especially in the arid west.

Diet
The diet includes large insects and small amphibians, reptiles, birds and their eggs, small mammals and rodents. The Secretary bird walks well on its long legs, and will walk roughly 40km per day. It finds most of its food on the ground and will stamp on grass tussocks to scare up lizards, grasshoppers, and small mammals or birds. Adults hunt in pairs, stalking through the habitat with long strides. It also waits near fires, eating anything it can that is trying to escape. Secretary Birds have two distinct feeding strategies that are both executed on land. They can either catch prey by chasing it and striking with the bill, or stamping on prey until it is rendered stunned or unconscious enough to swallow.

Breeding
Monogamous, territorial solitary nester. Secretarybirds pair for life and are remarkably faithful to their nest site. The nest is generally placed on top of a tree, usually a flat thorn tree. During courtship, they exhibit a nuptial display by soaring high with undulating flight patterns and calling with guttural croaking. Males and females can also perform a grounded display by chasing each other with their wings up and back, much like the way they chase prey. The nest is built by both sexes, consisting of a large flat platform about 1-1.5m wide, made of sticks and lined with grass. It is typically placed on top of a thorny tree. The breeding pair roost in the structure for several months before breeding, and may even use the nest for roosting only. Egg-laying season is year-round, peaking from April-May in Namibia but from September-December elsewhere. It lays two to three oval, rough textured, pale-green/white eggs over the course of two to three days. The eggs are incubated primarily by the female for 45 days. Both the parents feed the young and are fed liquefied and regurgitated insects directly by the male or female and are eventually weaned to small mammals and reptile fragments regurgitated onto the nest. At 60 days, the young start to flap their wings, and by 65 to 80 days are able to fledge.

Call
Mostly silent away from nest. Alarm near nest croaking korr-orr-orr.

Spoor


Status
Common resident. Generally not sedentary; very nomadic, especially in western regions. Usually in pairs, sometimes solitary.
The Secretarybird was uplisted from Near-threatened to Vulnerable. In South Africa there is considerable concern about the conservation status of the species. A preliminary analysis of SABAP1 and SABAP2 data shows a considerable reduction in the areas this species previously occupied. This is probably mostly due to habitat loss and habitat degredation, but other threats such as power lines collisions are also taking their toll.

[Lisbeth]

118. Secretarybird Sagittarius serpentarius

© Lisbeth
Kgalagadi Transfrontier Park

© Lisbeth
Kgalagadi Transfrontier Park

© Dewi
Kgalagadi Transfrontier Park

© ExFmem
Kgalagadi Transfrontier Park

© PRWIN
Kgalagadi Transfrontier Park

© Tina
Kgalagadi Transfrontier Park

© PJL
Mountain Zebra National Park

Links:
Species Text Sabap1
Sabap2
Sasol Birds of Prey of Africa
Global Raptors
Secretarybirds, in: Trevor Carnaby. Beat about the Bush: Birds
Oiseaux net
EDGE