Hamerkop



Scopus umbretta  


Length is about 20 inches.  Plumage is dark brown.  Bill and legs are black.  Voice usually silent, but utters wide range of high notes when flying or during courtship.  Its stiff, backward-pointing crest, along with its peculiar bill, gives the head a hammer shape appearance. Sexes are similar. In flight, it flies like a heron.  It has a “comb-claw” but no powder-down.  Average weight is between 465g and 500g.

Family

Scopidae

Order

Ciconiiformes

Class

Aves

Range

South and central Africa, lowland Madagascar, and southern Arabia

Habitat

Shallow freshwater lakes, ponds, swamps and marshes of open woodland to forested regions. During and after rains, it may move seasonally to areas that are normally dry.

Life Expectancy

Sexual Maturity

Diet

In the wild, they eat frogs, fish and invertebrates and sometimes scavenges near human habitation. In the Zoo, they are fed pinky mice, fish, mealworms, omnivore diet and bird of prey diet (the latter two are scientifically, commercially prepared diets).

Status

IUCN - Least Concern

Behaviors

This species is typically found in pairs, sedentary and remains in well-defined territories near water. It is not uncommon to find them perched on the backs of hippopotamuses, searching for frogs. Some pairs, however, may move to normally dry areas when the seasonal rains arrive. Often claimed to be nocturnal, it is actually active only during the day. But, like many African birds, it feeds in the cool of the dawn and dusk, and roosts calmly during the heat of the day. Hamerkops have also been observed in “group ceremonies,” usually near a nest. As many as 10 birds may call loudly while running around each other in circles, a male sometimes mounting a crouching female and pretending to copulate. Crests are raised, wings fluttered, and a chorus of cries continues for several minutes. True mating is usually done at individual nest sites, and may be preceded with displays similar to those observed during “group ceremonies.” The nests, to which the birds return each year, are complex, three-compartmented structures, lined with mud and dung, and ornamented outside with bright-colored objects. Measuring approximately 6 feet (1.8 m) wide and 6 feet (1.8 m) high and weighing 55-110 lbs. (24 to 50 kg). The selection of a suitable site requires a large tree, rock or cliff strong enough to hold the nest. The nest entrance must be high enough to deter predators, especially man, but there seems to be no limit to how high above ground they place the nests. It usually takes about six weeks to build the nest. Work starts at first light and goes on for about two or three hours daily. Normally the female remains at the nest while the male collects sticks and other items, which she arranges as a platform and then raises the sides to form a huge basin. Both birds bring in mud to plaster the nest so that the structure is extremely strong. Once the chamber is as high as the bird stands they build a roof, which is a dome of sticks and mud. The entrance faces outwards and downwards so that it is difficult for predators to enter. Towards the end of construction, the birds will bring in various unusual items for decoration, such as feathers, sloughed off snake skins, and so forth. They may even pick up man-made objects like old pots and plastic. The female lays a clutch of three to six white eggs. Both sexes incubate the eggs (30+ days) and care for the highly dependent young. The nest would be big enough to house eight full-grown chicks if food was plentiful and all the chicks survived to fledge. The chicks are fed on aquatic organisms, with frogs being a major portion of their diet. The adults catch Platanna frogs and tadpoles (Xenopus laevis) by feeling for them in the mud of shallow pans and rivers. Chicks hatch with a coat of gray downy feathers, but feathers quickly develop. By 17 days, the head and crest feathers have come in; and by 30 days the rest of the body plumage has grown in. Chicks take their first flight at 7 weeks. When the chicks fledge, they may use their nest to roost in at night for up to a month after fledging.

Adaptions

The hamerkop is a common and familiar bird throughout Africa south of the Sahara. It adapts rather well to the presence of man. Its short tail and long wings enable it to glide and soar easily. If disturbed, however, it will only fly a short distance.

Special Interests

This strange bird is the only member of the Scopidae family. The name “hamerkop” is derived from the hammer-shaped head, which in Afrikaans / Dutch means “hammerhead”. The origins and relationships of the hamerkop to other birds are obscure. It has a pectinated middle toe as in the herons, a free hind toe as in the flamingos, egg-white protein like the storks, and is susceptible to ectoparasites typically associated with plovers. Its habits and behavior are unique, leaving taxonomists with little option but to place it in its own monospecific family. The hamerkop nest is extremely durable and can be used by the birds for several seasons. It is strong enough for a man to jump on without damaging the roof. When the hamerkops have finished using it, it is highly prized by other species, such as barn owls or Dickinson’s kestrels. As the nest starts to collapse, one may find Egyptian geese nesting inside or on top. Giant eagle owls also nest on the top. Paper wasps may build their nests under the shelter of the huge structure. Some weavers will also attach their nests under the hamerkop’s nest for protection. Thus, while it cannot be explained why the hammerkops invest so much time and energy in nest building, their presence provides nesting sites for numerous other species that otherwise would find no suitable place for breeding in the area.

Folklore

It has been claimed that this species is the origin of more legends and superstitions than any other bird. It is considered “magical” because of its large, impenetrable, inaccessible and therefore mysterious nest. According to native superstitions, hamerkops are evil omens, and it is considered bad luck to harm them. Such superstitions have kept the birds somewhat protected. The hamerkop is called the lightning bird. In some parts of Africa, there is a legend that if the bird lands on your house, it will be struck by lightning. While it seems very unlikely that this is true, no doubt it once happened. The parents peculiar habit of “decorating” the nest with a variety of items such as small animals, fur and bones led to superstitions in local cultures that this bird had magical powers, since the collecting of these items resembled the habits of tribal medicine men. In other African cultures, people view the hammerkop with such superstitious awe that they will go as far as removing their huts if a hammerkop is seen to fly directly over it.

Conservation

Jacksonville Zoo History

Exhibit

River Valley Aviary