[order] CICONIIFORMES | [family] Ciconiidae | [latin] Anastomus lamelligerus | [authority] Temminck, 1823 | [UK] African Openbill | [FR] Bec-ouvert africain | [DE] Mohren-Klaffschnabel | [ES] Picotenaza Africano | [NL] Afrikaanse Gaper
The openbill storks or openbills are two species of stork (family Ciconiidae) in the genus Anastomus. They are large wading birds characterized by large bills, the mandibles of which do not meet except at the tip. This feature develops only in the adults. The two species of openbill storks are the Asian Openbill (A. oscitans), a resident breeder in tropical southern Asia from India and Sri Lanka east to Southeast Asia. Next the African Openbill (A. lamelligerus,) a resident breeder in Africa and Madagascar.
Both adults are similar, with male larger than female.
The plumage is black overall, with glossy green, brown or purple mantle and breast.
The large bill is brownish-horn, paler towards the base. The mandibles show a wide gap between them of about 5-6 mm, and join only at tip. On the almost straight upper mandible, there are several small columnar pads, about 20-30, which help the bird to grip the shell and then, to extract the mollusc.
Eyes are grey with bluish lores and bare eye-ring. Legs and feet are blackish.
Listen to the sound of African Openbill
Copyright remark: Most sounds derived from xeno-canto
recorded by Derek Solomon
Africa : widespread. Africa s. of the Sahara in unforested regions; W. Madagascar
The species inhabits freshwater wetlands with shallow waters and a large abundance of aquatic molluscs including marshes, swamps, rice-fields, flood-plains, the backwaters and margins of lakes or rivers, ponds and streams. It may also frequent moist savanna or burnt grassland as well as occasionally forest clearings, coastal mudflats and mangrove swamps
The nest is a small platform of sticks and vegetation positioned in trees and bushes over water (e.g. inundated in standing water on flood-plains), or alternatively in reedbeds. It nests colonially, often in mixed-species groups. The African Openbill is monogamous unless its mate dies. In the event of a partner dying Anastomus lamelligerus will seek out a new mate. The nesting habit of African Openbill is to create the nest on the ground. Female lays 3-4 oval, chalky-white eggs. Incubation is shared by both sexes and lasts about 25-30 days. At hatching, the downy chicks are black with normal bill. The gap will develop over several years. They are fed by both parents, and fledge about 50-55 days after hatching.
It breeds during in the rains when snails (its main prey items) are most readily available and nests in colonies of various sizes1 often with other species. Nesting may only occur in years when local food supplies are plentiful however, so may not occur regularly at the same site. In many regions the species may depend entirely upon molluscs such as aquatic snails and freshwater mussels. Other prey items taken include frogs, crabs, worms, fish and insects (e.g. locusts and beetles).
copyright: Daniel Jimenez
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The species is threatened by habitat loss, entanglement in fishing lines and environmental pollution (e.g. pesticides applied to water for mosquito control). It also suffers from hunting, poaching and the destruction of breeding colonies by villagers on Madagascar. Utilisation The species is hunted and traded at traditional medicine markets in Nigeria.
This species is an intra-African trans-equatorial migrant making movements that are triggered by the rains.