Whalehead, Whale-headed stork, Shoe-billed stork
The shoebill (Balaeniceps rex) is a very large stork-like bird. It derives its name from its enormous shoe-shaped bill. It has a somewhat stork-like overall form and has previously been classified with the storks in the order Ciconiiformes based on this morphology. However, genetic evidence places it with pelicans and herons in the Pelecaniformes.
The plumage of the adult shoebill is blue-grey with darker slaty-grey flight feathers. The breast presents some elongated feathers, which have dark shafts. Juveniles have a similar plumage color but are darker grey with a brown tinge. When they are first born, shoebills have a more modestly-sized bill, which is initially silvery-grey. The bill becomes more noticeably large when the chicks are 23 days old and become well-developed by 43 days.
Shoebills are found in central tropical Africa, from southern Sudan and South Sudan through parts of eastern Congo, Rwanda, Uganda, western Tanzania, and northern Zambia. They are non-migratory and only make limited seasonal movements. Shoebills occur in extensive, dense freshwater swamps and marshes. Almost all wetlands that attract these birds have undisturbed papyrus and reed beds, however, they tend to avoid pure papyrus swamps and are often attracted to areas with mixed vegetation. More rarely, shoebills can be found foraging in rice fields and flooded plantations.
Shoebills are noted for their slow movements and tendency to stay still for long periods, due to which they are often described as "statue-like". They are quite sensitive to human disturbance and may abandon their nests if flushed by humans. However, while foraging, if dense vegetation stands between them and humans, these waders can be fairly tame. Shoebills typically feed by day in muddy waters and, being solitary, forage at 20 m (66 ft) or more from one another. They stalk their prey patiently, in a slow and lurking fashion. While hunting, the bird strides very slowly and is frequently motionless. Unlike some other large waders, shoebills hunt entirely using vision and do not use tactile hunting. When prey is spotted, they launch a quick violent strike. The birds may also sometimes use their big beak to dig into pond-bottom mud to extract lungfish from their aestivation burrows. Shoebills are normally silent, but they perform bill-clattering displays at the nest. When engaging in these displays, adult birds may also utter a cow-like 'moo' as well as high-pitched 'whines'. Both nestlings and adults engage in bill-clattering during the nesting season as a means of communication. When young are begging for food, they call out with a sound uncannily like human hiccups.
Shoebills are carnivores (piscivores); they feed mainly on fish but are assured predators of a considerable range of wetland vertebrates. Preferred prey includes marbled lungfish, Senegal bichir, various Tilapia species, and catfish. These large birds will also eat frogs, water snakes, Nile monitors, and baby crocodiles. More rarely the shoebills will consume turtles, snails, rodents, and small waterfowl.
Shoebills are serially monogamous and form pair bonds only for the breeding season. Pairs nest solitarily and vigorously defend their territory from conspecifics. In the extreme north and south of their range, nesting starts right after the rains end. In more central regions of the range, shoebills may nest near the end of the wet season. Both parents engage in building the nest on a floating platform, after clearing out an area of approximately 3 m (9.8 ft) across. The large, flattish nesting platform is often partially submerged in water and can be as much as 3 m (9.8 ft) deep. Both the nest and platform are made of aquatic vegetation. The female lays 1 to 3 white eggs and both parents incubate them for approximately 30 days. Shoebills rarely raise more than one chick because the younger chicks eventually die and are intended as "back-ups" in case the eldest chick dies or is weak. Fledging is reached at around 105 days and the young birds can fly well by 112 days. However, they are still fed for possibly a month or more after this. It will take the young shoebills 3 years before they become reproductively mature and start to breed.
The main threats to shoebills include habitat destruction, disturbance, and hunting. The birds are also caught and sold to zoos. Other important reasons for the decline in populations include expansion of the agriculture, construction of roads and dams, pollution, fires, and droughts
According to the IUCN Red List, the total shoebill population size is around 5,000-8,000 individuals, which roughly equates to 3,300-5,300 mature individuals. Currently, this species is classified as Vulnerable (VU) on the IUCN Red List site and its numbers today are decreasing.
