The breeding behaviour of the Indian Grey Hornbill – An Inside View by Ajay Gadikar
Updated: May 3, 2021
By Ajay Gadikar
This is an article about the breeding behavior of the Indian Grey Hornbill (Ocyceros birostris) observed at the bio-diversity park in the Residency area in Indore city.I have been observing the Indian Grey Hornbill (IGH) in the Residency area of Indore since the last 5 years. I always get mesmerized when I see these birds, firstly due to their very peculiar casque (horn) over their bill and secondly their undulating type of flight. The Residency area in Indore is full of old fig trees like Pipal, Banyan, Gular and also the Jamun. These trees are like magnets which attract the hornbills since these figs comprise most of their diet. I used to see them mostly in the morning moving high up in the canopy as they are mostly arboreal in nature. Their breeding period, which is from March to May-Jun, coincides with the ripening of fruits in all the fig trees. During this period there is sufficient food available in the form of fruits of these trees which helps the parents to fulfill the demands of the growing chicks. Outside their breeding season these birds are frequently seen in the morning and evening feeding and indulge in various social interactions like bill grappling, aerial jousting and erratic chases in the higher canopy of trees. I would like to share with you my experience with the nesting behavior of these birds as recorded and unveiled by using a camera. I had watched a natural hole on a Gulmohar tree which a hornbill pair had used for nesting purposes in the last season. With the help of the forest department a CCTV camera, capable of zooming in and out was installed 5 meters away from the nest to record the whole breeding cycle almost for a period of 3 months. A 11 minute documentary film “UDAN” was made based on the important footage obtained from the 24×7 recording. This film was inaugurated by the Chief Minister of Madhya Pradesh. I would like to share the following details about the general breeding behavior of the IGH. Their nesting is very unique. When it is time to lay eggs, the female hornbill enters the hole of the tree trunk and does not step out into daylight again, until it hatches the eggs and the babies are at least one and half month old, which means she remains under the nest cavity for 60 to 65 days. The female starts to seal the nest cavity once she enters inside. Only a narrow slit of size 3-4 cm by 7-8 cm remains open, from where the male feeds the female. The material used to prepare the wall of the nest cavity are mud, fruit pulp and her own droppings. The female now solely depends on the male for her food. The male fetches fig and berries from nearby trees and feeds the female, approximately once in an hour throughout the day. Most of the feeding took place early in the morning. The male carries 5-8 berries and 1-2 insects in his mouth in one go and regurgitates them one by one into the female beak by clinging to the nest. Once inside the nest, the female lays the eggs and incubates them. Soon the chicks come out of the egg. At the same time the female also undergoes complete moult, by shedding all her feathers. This is a really vulnerable time for the family as the female bird cannot fly and cannot feed the chicks, the family is totally dependent on the male bird. If something happens to the male bird and if he dies, then the entire family can die due to starvation. During the nesting the male bird feeds the female and the chicks with a variety of fruits, and also small insects, grasshoppers, lizards etc. It travels long distances in search of food. The fruits are held in its throat and when it reaches the nest it regurgitates the fruit one by one from its pharynx to its beak and feeds the female which does not come out and receives the feed by putting its beak out. When the chicks are sufficiently grown the female breaks open the nest and comes out and both parents feed the young ones. These birds use the same tree and nest repeatedly and come back to the same place in their next breeding cycle. The camera study for 3 complete months of the Hornbill nesting was done first time ever and it confirmed many of the points which scientists have written in journals over the years.