Shoebills

(Balaenicipitidae)

Class Aves

Order Ciconiiformes

Suborder Ciconiae

Family Balaenicipitidae

Thumbnail description
This is a large gray wading bird with a very large bulbous bill tipped with a hooked nail; legs are long with long toes allowing the bird to walk on submerged aquatic vegetation; in flight the neck is retracted like herons; not outstretched as in storks

Size
4 ft (120 cm); wing: 31 in (780 mm); bill: 7.5 in (191 mm); male slightly larger than female

Number of genera, species
1 genus; 1 species

Habitat
Swamps, primarily papyrus swamps or cattail marshes

Conservation status
Near Threatened

Distribution
Central Africa: Sudan, Uganda, Tanzania, Democratic Republic of Congo, Central African Republic, and Rwanda

Evolution and systematics

The shoebill (Balaeniceps rex), with one genus and species, has been placed within its own family and has traditionally been allied with the storks and/or herons. It was first classified in 1850 by Gould, who spotted the creature along the banks of the upper White Nile and called it "the most extraordinary bird I have seen for many years". Suggestions that it is related to pelicans based on skull structure have been discounted, although recent DNA analyses support this relationship.

Physical characteristics

The shoebill stands about 43–55 in (110–140 cm) tall. The bird is gray to blue-gray with an ashy gray crown. Most prominent is the enormous, almost bulbous, prominently hooked bill, which resembles a shoe and lends the bird its common name. The bill is yellowish with irregular dark patches. The toes are long: 6.6–7.3 in (16.8–18.5 cm) long and completely divided; the claw of the hind toe is larger than those on the fore-toes. In flight, the neck is retracted as in herons; not outstretched as in storks. The female is similar in all respects but slightly smaller than the male.

Distribution

Central Africa: Most populous in southern Sudan and northern Uganda, but also found in Tanzania, Democratic Republic of Congo, Central African Republic, and Rwanda.

Habitat

Swamps and marshy lakeside, usually where papyrus (Cyperus papyrus) or cattails (Typha spp.) are dominant.

Behavior

Generally solitary. At favored locations, several birds may fish near each other. Shoebills are slow-moving, sedentary birds that are silent, except during nest building, when they make clapping noises with their bills.

Feeding ecology and diet

Shoebills use a stand-and-wait approach, although they occasionally feed by walking slowly. A shoebill stands with bill

pointed downwards, almost motionless, sometimes for over thirty minutes. When prey is sighted, the shoebill thrusts its whole body forward, wings outstretched, as the bird attempts to seize its prey. The vegetation is separated from the prey. Prey is often decapitated. The shoebill usually swallows water after feeding. If the feeding attempt is unsuccessful, it usually moves to new location.

Shoebills feed primarily on lungfish (Protopterus aethiopicus), bichirs, catfish and other fish. Because shoebills feed in stagnant swamps, fish prey are caught when they come to the surface for air.

Reproductive biology

Nests singly in monogamous pairs. The nest is made of aquatic vegetation and measures up to 8 ft (2.5 m) across. When nests are built in the swamp, supplementation may be necessary to counteract sinking; sometimes the nest is built on a solid mound.

One to three (usually two) dull white eggs are laid. The eggs measure 3–3.5 in (80–90 mm) by 2–2.5 in (55–63 mm) and weigh about 6 oz (165 g). Eggs are laid at intervals of up to five days. Both birds incubate for about 30 days. During hot weather the parents may bring water that they regurgitate to cool the eggs.

At hatching, the young are downy, white, or silvery gray. The young stay in the nest for up to 105 days. During the first 35 days, they cannot stand and are brooded by the adults. Following this, parents spend less time at the nest while collecting food for the chicks. Feathers develop. By 95 days, the young begin to wander off the nest and they can fly about ten days later.

Both parents feed and care for the young. In addition, parents cool their young by bringing water and pouring this over the chicks. The parents may do this as many as five times on hot days.

Usually only a single chick fledges.

Conservation status

Near Threatened. Total population is estimated at 12,000–15,000 birds.

Significance to humans

None known.

Resources

Books

BirdLife International. Threatened Birds of the World. Barcelona: Lynx Edicions; and Cambridge, United Kingdom: BirdLife International, 2000.

Brown, L.H., E.K. Urban, and K. Newman. The Birds of Africa. Vol. 1, Ostrich to Falcons. London: Academic Press, 1982.

Collar, N.J., and S.N. Stuart. Threatened Birds of Africa and Related Islands. Cambridge, United Kingdom: ICBP, 1985.

del Hoyo, J., A. Elliott, and J. Sargatal, eds. Handbook of the Birds of the World. Vol. 1, Ostrich to Ducks. Barcelona: Lynx Edicions, 1992.

Hancock, J.A., J.A. Kushlan, and M.P. Kahl. Storks, Ibises and Spoonbills of the World. London: Academic Press, 1992.

Sibley, S.G., and J.E. Ahlquist. Phylogeny and Classification of Birds. New Haven: Yale University Press, 1990.

Periodicals

Collar, Nigel J. "Shoebill." Bulletin of the African Bird Club 1 (March 1994).

Sibley, C. G., and J. E. Ahlquist. " Phylogeny and Classification of Birds Based on the Data of DNA-DNA Hybridization." Current Ornithology 1(1983): 245–292.

Malcolm C. Coulter, PhD