Stork, Marabou



Leptoptilos crumeniferus 


Adult height: 43–55 in (120–140 cm); adult weight: 10-18 lbs (4.5–8 kg); wingspan: 89–113 in (225–285 cm); appearance and coloration: bare head and neck, black back, and white underparts, huge bill, a pink gular sac at its throat, a neck ruff, and black legs and wings; sexes are alike, but the young bird is browner and has a smaller bill.

Family

Ciconiidae

Order

Ciconiiformes

Class

Aves

Range

Sub-Saharan Africa; vagrant in Israel, Liberia and Spain

Habitat

Open dry savannas, grasslands, swamps, riverbanks, lake shores and receding pools where fish are concentrated

Life Expectancy

Up to 25 years (potentially longer in captivity)

Sexual Maturity

About 4 years

Diet

In the wild, they eat primarily carrion, but will also take fish, frogs, insects, eggs, small mammals and reptiles; in the Zoo, they are fed a scientifically developed, commercially available bird of prey diet, thread herring, capelin, chicks, and vitamins and minerals.

Status

IUCN – Least Concern

Behaviors

The marabou stork is sedentary or locally nomadic. Populations in the north and south generally move towards the equator after breeding with other populations dispersing in relation to water availability or prey abundance. In the tropics the species begins to breed in the dry season, but in the equatorial zone the timing of breeding is more variable. It breeds in colonies numbering from 20-60 up to several thousand pairs and often nests with other species. When it is not breeding, the species often remains gregarious, feeding in groups and gathering at night in communal roosts of up to 1,000 individuals. It may also associate with herds of large mammals in order to catch insects disturbed by their movements. Typically, the marabou stork soars at height, scanning the ground for food, and often congregates around large carcasses with other scavengers such as vultures. This species has taken full advantage of the encroachment of human settlements, frequenting dumps, slaughterhouses and fishing villages for discarded scraps. The marabou stork is gregarious and a colonial breeder. In the African dry season (when food is more readily available as the pools shrink) it builds a tree nest in which two or three eggs are laid. Males arrive first and establish a territory, whereupon they greet all newcomers with hostility, whilst inflating throat pouches. Black spots on the male’s head become even more numerous during the breeding season. The black spots are actually scabs, and the more scabs a male has, the more attractive he is to females. Eventually, a courting female will be accepted by the male, and the pair will set about building a stick nest. Pairs are monogamous and usually mate for life. The nest is constructed of sticks and is positioned 32.8 to 98.4 ft. (10-30 m) above the ground in trees, on cliffs or on buildings in towns and villages. The nests are very large constructions, and many smaller birds will nest amongst the twigs. The female Marabou Stork usually lays two to three eggs at a time, and the incubation period is 29 to 31 days. Both parents will scavenge for food to feed the chicks, and after about four weeks the chicks are able to stand. It takes a few months for the chicks to grow flight feathers, but they fledge at about 13 to 15 weeks. Even after they are able to fly, they still remain dependant on their parents for several more weeks. Like other storks, the marabou stork is not very vocal (occasionally grunts and croaks), but indulges in bill-rattling courtship displays. The throat sac is also used to make various noises at that time. When the marabou storks take flight, they are extremely elegant and fly with their legs outstretched and necks resting in an “S” position.

Adaptions

The marabou stork is a frequent scavenger, and the naked head and neck are adaptations for this lifestyle. Pieces of decaying meat and skin are less apt to stick to bare heads and necks than to a thick mat of feathers. When marabous bask after meals, the heat of the sun dries any potentially bacteria-ridden bits of food that easily fall off, helping them remain healthy.

Special Interests

The marabou stork is sometimes called the “undertaker bird,” due to its shape from behind: cloak-like wings and back, skinny white legs, and sometimes, a large white mass of “hair.” A number of endoparasites have been identified in wild Marabous including Cheilospirura, Echinura and Acuaria nematodes, Amoebotaenia sphenoides (Cestoda) and Dicrocoelium hospes (Trematoda). Marabou down is frequently used in the trimming of various items of clothing and hats, as well as fishing lures. The tail feathers, called marabou, were once used to trim hats and gowns and to make scarves. Feathers are stilled used today in lingerie. Interestingly marabous were scarce across East Africa in the early part of the 20th Century. Their present abundance can be explained by the increase in the human population and the consequent rise in the amount of human waste. An increase in the number of food processing plants (battery farms, abattoirs, fish processing factories, etc.) and refuse dumps have undoubtedly contributed to their success.

Folklore

This species is hunted and traded at traditional medicine markets in Nigeria.

Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion. The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion. The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion. For these reasons the species is evaluated as Least Concern.

Jacksonville Zoo History

At the Jacksonville Zoo since 1979, we have one of the more successful breeding histories in North America for this species.

Exhibit

Plains of East Africa