Generally a solitary bird, the lesser adjutant only forms groups during the breeding season. This occurs at the beginning of the dry season, which varies geographically. Small, loose colonies of lesser adjutant construct their nests in patches of tall trees that have a thick undergrowth of bamboo and are located on the edge of suitable wetlands. Courtship is lengthy, starting three months before eggs are laid. The nest consists of a large, flat platform of sticks lodged between thick branches of a tall tree. The male selects the nest site, carrying twigs to it to indicate his choice, as nests usually remain intact from one year to the next. Between one and four eggs are laid and are incubated for 28 to 30 days. The hatchlings emerge weak and sparsely feathered. Both parents tend to the eggs and bring food to the hatchlings (3).
The lesser adjutant feeds on frogs, fish and small reptiles (3).