The Sri Lanka Grey Hornbill (Ocyceros gingalensis) was first described in 1811 by Shaw. It is a member of the family Bucerotidae (Hornbills). Hornbills are a family of tropical near-passerine birds found in the Old World. Sri Lanka has two species of Hornbills, the Grey Hornbill which is endemic to the island and the Malabar Pied Hornbill (Anthracoceros coronatus) which is also found in other parts of South Asia. The Grey hornbill can be easily set apart from its counterpart (Malabar Pied Hornbill) by lacking the casque (the projection on top of the bill).
The family Ocyceros is represented by three species, which is distributed throughout South Asia; the Malabar Grey Hornbill (Ocyceros griseus), the Indian Grey Hornbill (Ocyceros biostris) and the Sri Lankan Grey Hornbill (Ocyceros gingalensis).
Hornbills have rather intriguing way of raising a brood; the female lays around 4 eggs in a tree hole. Once the egg are laid, the male blocks off the entrance to the hole, trapping the female inside, with a mixture of mud, droppings and fruit pulp. The male leaves a narrow opening, just wide enough to transfer food to the mother and chicks. During the incubation period the female drops (moults) all her feathers. And once the chicks are ready to leave the hollow the female and male break open the hollow, helping the female and chicks to come out. The feathers of the female grow back at the end of this period.