The diet of the yellow-billed stork comprises frogs, small fish, aquatic insects, worms, crustaceans, small mammals and birds (2) (6). This species is a patient feeder and will submerge its bill into the water until contact is made with its prey, at which point the head is flipped back and the catch swallowed. The yellow-billed stork has been known to wait while crocodiles or hippopotamus feed, before approaching to eat the organisms which have been stirred up (2).
During the night, the yellow-billed stork forms communal roosts at favoured sites surrounding the wetland, for example, on sandbanks or in trees. These roosts are often shared with other species (6).
The yellow-billed stork sometimes migrates to areas where the feeding conditions are more favourable, especially throughout periods of heavy rain. However, some populations are known to be sedentary (6). The most likely reason for this migration in this species is rising water levels creating poor hunting conditions (2).
Breeding in the yellow-billed stork is seasonal and dependent on the abundance of food. Breeding usually begins towards the end of the rainy season or at the beginning of the dry season, when food is readily available, the rainy season lasting from November through to May (6) (7). The yellow-billed stork breeds in colonies, although it will never form a flock of more than 50 individuals (6).
The nest of the yellow-billed stork consists of sticks positioned in a small tree over water, or elevated higher in a tree on dry land. There may be 10 to 20 pairs in each tree, sometimes of different species, with each nest separated by 1 to 3 metres (2) (6). The male and female yellow-billed stork share responsibility for incubating the eggs, brooding, guarding and feeding the young (2).
The German common name of this species is ‘Nimmersatt’, meaning never full, due to the eating habits of the nestling, it increases from 60 grams to 500 grams in weight within the first ten days of life (2).