Diving ducks are gregarious and are mainly found on fresh water, large, deep lakes and rivers, coastal bays and inlets. They feed almost exclusively on aquatic plant seed, small fish, molluscs, grasses and other small insects and animals by diving beneath the surface of the water. Their beaks are long and narrow and have saw-like edges enabling them to grab slippery food. They are heavier than dabbling ducks and because their wings are smaller in proportion to the size and weight of their bodies, they have to beat their broad, blunt-tipped wings faster than many other ducks. It is more difficult for them to take off and therefore need a running start on the water to get airborne, but they are strong fliers.
The White-backed Duck is considered a diving duck together with the Southern Pochard and the Maccoa Ducks. They are known as the stiff-tailed ducks. Whilst swimming the tails are carried low, turned down towards the water and their wing speculums lack the brilliance of most other dabblers. Although our own Southern Pochard belonging to the genus Netta is supposed to be a diving duck, it is not always behaving as such. Unlike other diving ducks, the Netta species are reluctant to dive, and feed more like dabbling ducks on or directly beneath the water surface and may also be seen filtering mud on the shoreline. The Maccoa duck has a distinctive stiff tail that is either kept flat on the water surface or cocked upright. The body is kept low in the water when it is alarmed or when displaying during courtship. It is the only stiff-tailed duck species in the region. The Maccoa and White-backed Ducks build their nests over deep water and the nest of the Southern Pochard is built over shallow water in flooded grass.
The South African Shelduck belongs to the genus Tadorninae, a group of larger often semi-terrestrial waterfowl which can be seen as somewhat intermediate between geese and dabbling ducks. They breed away from water, sometimes in an antbear hole.
The African Pygmy Goose is not a goose but Africa’s smallest duck and although a dabbling duck will also dive for food. They belong to a group of very small ‘perching ducks’ in the genus Nettapus and usually nest in tree cavities.
Another fairly large perching duck species is the Knob-billed Duck. They sometimes perch in trees, clinging with their strong claws to vertical tree trunks and also nest in tree cavities about 6–9 meters above the ground. Through DNA analysis it is suggested that it is a basal member of the Anatidae family in the genus Sarkidiornis and that it does not have any close relatives.
Other species in the Order Anseriformes include the larger geese family, the Egyptian Goose from the genus Alopochen and the Spur-winged Goose from the genus Plectropterus. The Egyptian Goose and Spur-winged Goose are found on wetlands, in cultivated lands and in urban areas. They are almost exclusively herbivorous, feeding mainly on plant matter, grass, seeds and aquatic plants in and around water bodies. Both are also considered as perching birds and may breed in holes, tree hollows or in thick cover on the ground.
Ducks are unique and delightful birds, though they can be easily overlooked by both novice and experienced birders. Ducks are uniquely specialised for different types of habitats, climates and diets and it can therefore be quite tricky to identify ducks in their natural habitat. While male ducks can easily be identified by sight alone, hens with their dull-brown feathers can be more challenging. With practice, it is possible to identify them confidently by looking at the differences in size, shape, plumage and colour patterns, wing beat, habitat, flock behaviour, aerial manoeuvres, and their calls. Listening to and learning the extent of their vocabularies which can include quacks, whistles, honks, hisses, grunts, squeaks growls, hoots, purrs, coo’s or chatters could also be of great help. Another clue can be the sound their wings make in flight. Studying these different duck identification tips can help you to easily and correctly identify every duck you see.