These birds primarily feed on aquatic snails of the genus
Pila. They have been observed to also eat freshwater mussels. In different parts of their range, some individuals have been observed to eat terrestrial snails, frogs, crabs, fish, worms and large insects. It is important to note, that none of these are the preferred food choice of the African openbill.
Foraging To forage for snails, the African openbill stands in shallow water, repeatedly dipping its beak in. They hold their bill slightly ajar and will snap it shut if they encounter a prey. Once they have a hold on the prey, they hold it with the tip of their mandibles and carry it back to shore. The storks will start slowly walking around and changing location, if they do not capture anything in the area they decided to forage in. The African openbill sometimes forages by standing on the back of
hippopotamuses (
Hippopotamus amphibius). As the hippopotamus wades through the vegetation, it upturns it and exposes the multiple snails that cling to the undersides of the plants. The stork will then feed on these exposed snails that have become easy prey. The hippopotamus does not seem to mind the presences of the bird on its back and is not harmed by it in any way. Lastly, very few individuals have been observed to
forage visually from afar. There are accounts of African openbill storks swooping down from their nest and immediately securing a prey. This behavior is extremely uncommon for the stork but does occur.
Feeding behavior Nestling feeding behavior The nestlings of the African openbill stork never voluntarily eat anything else than molluscs. Even when extremely hungry, the nestlings will not ingest other types of meat unless being force-fed. The nestlings have been observed as unaware of how to consume fish. When presented with them, the young African openbill would try to swallow them sideways or backwards as it is not instinctive to them how to consume those food items. The young feed in the nest through
regurgitation from the parents. When eating, the nestlings bring their wings over their head in an attempt to protect their food from being stolen by competing nest mates. In nestlings, the sides of the lower mandible are flexible, and the
gular skin is loose and elastic which allows them to swallow large pieces of food relative to their size. The
esophagus is expandible and permits storage of food. The nestlings can ingest large quantities of food when available which allows them to survive relatively long periods of time with no food intake.
Adult feeding behavior The adults either feed alone or in large groups. If a colony has found a successful foraging area, they often return to it and piles of snail shells can be seen accumulating on the shores. During nesting season, the African openbill adults will bring the food items back to their nest and these large piles of shells can be seen accumulating under the colony's tree.
Opening of mollusks Once the storks capture a
mollusc, they carry their prey to shore for extraction and consumption of the meat. The African openbill are well known for removing the meat of the molluscs without breaking their fragile shells.
Snails Most of this procedure is done underwater or hidden in vegetation, therefore there are still a lot of unknowns surrounding how exactly the African openbill removes the meat from the snail shells. Scientists know that the storks often submerge their head in the water while working on the shells and that they vigorously shake their heads up and down while doing so. This vigorous motion of the head led many scientists to incorrectly conclude the storks were crushing shells. Freshly discarded shells have been collected in multiple studies and have always been found whole, therefore discrediting the hypothesis of the storks breaking the shells to obtain the mollusc meat. The African openbill storks are believed to remove the snails from their shells by using their bills to pin the snails down long enough for the bird to sever the
operculum. This is achieved by using the tip of the upper mandible to hold the snail on the ground and forcing the tip of the lower mandible under the operculum. Once the attachment point has been broken, the stork uses the tip of its bill to grasp onto the snail's body and shakes its head sideways to release the meat from the shell. Finally, the stork swallows the body whole by tossing its head backwards.
Mussels Opening mussels poses a bigger problem to the storks. Since the African openbill can't open the mussel by itself, it will usually gather them up in large piles on the shore and wait for the sun to kill them. Once dead, the mussels release their hold on the shells leaving the meat accessible to the birds. == Habitat ==