Elaborate process: In this May 2024 photograph, a Great Hornbill pair, with their recently fledged chick, rest on a tree in a plantation in the Valparai plateau near Coimbatore. Large cavities are needed for the Great Hornbill to lay eggs as the females weigh up to 2.15 kg-3.35 kg as against males that weigh up to 2.6 kg-3.4 kg. After the female enters the cavity, the entrance is partially sealed with droppings, with an opening left for her to receive food brought by the male. The female comes out a few days before the chicks fledge and the nesting cycle lasts 102-140 days.
| Photo Credit: M. Periasamy

To conserve four species of hornbills found in Tamil Nadu, the State government is coming up with a blueprint to protect the ‘feathered foresters’ as these magnificent birds are referred to. The sobriquet suits them well: these frugivorous birds perform a significant ecological restoration work, dispelling a large variety of seeds through droppings and regurgitation.

Tamil Nadu’s proposal to establish a Centre of Excellence for Hornbill Conservation is significant as the State boasts the last remaining habitats of four of the nine hornbill species found in India — the Great Hornbill, the Malabar Pied Hornbill, the Indian Grey Hornbill, and the Malabar Grey Hornbill. While the Great Hornbill and the Malabar Grey Hornbill are listed in the ‘vulnerable’ category of the IUCN Red List, the Malabar Pied Hornbill is described as a ‘near threatened’ species. The Indian Grey Hornbill, with widespread distribution in the country, is in the ‘least concern’ category.

No comprehensive count

Though various organisations have studied the hornbill populations in specific regions of Tamil Nadu, a comprehensive estimation of their population is yet to be done. “No one has estimated the population of hornbills in the entire mainland so far. What we know have come from surveys in specific areas. We know where different species of hornbills are found. But population estimation requires more work. That is why, the initiative of the Tamil Nadu government is significant. After the launch of Project Nilgiri Tahr, the [Forest] Department has a very good idea of the population of the Tahr in the whole of Tamil Nadu. This will give us an opportunity not only to find out where all hornbills are found but also to estimate their population,” says T.R. Shankar Raman, a wildlife scientist attached to the Nature Conservation Foundation (NCF), who has studied hornbills for several years, especially in the Anamalais.

Based on studies done by various organisations and institutions in the past, the Forest Department has identified key areas for hornbill conservation — the Anamalai Tiger Reserve (ATR) for the Malabar Grey Hornbill and the Great Hornbill; the Athikkadavu-Pilloor-Bhavanisagar Valley for the Malabar Pied Hornbill; and the drier forests like Sathyamangalam for the Indian Grey Hornbill.

According to Supriya Sahu, Secretary, Environment, Climate Change, and Forest, the Centre for Excellence for Hornbill Conservation will be established in the ATR. Identification and protection of nesting trees, including those on private land, developing guidelines for safeguarding nesting trees in and outside the protected areas, and population estimation are the key components of the initiative aimed at securing a thriving future for the hornbills. It is also aimed at taking up ecological restoration to plant and protect key food and nesting trees, including Dipterocarpus indicus, Cryptocarya anamalayana, and Myristica malabarica.

“These trees are very important for the hornbills to nest. They are rare species. Among them, Dipterocarpus indicus and Cryptocarya anamalayana are ‘endangered’, according to the IUCN Red List, while Myristica malabarica is ‘vulnerable’,” says A. Rajasekaran, scientist ‘F’ of the Forest Ecology and Climate Change Division of the Institute of Forest Genetics and Tree Breeding, Coimbatore.

‘Protect the nesting trees’

Experts say protecting the trees that offer these birds food and the cavities for nesting, and raising new trees are key to sustaining their populations. Hornbills are secondary cavity nesters: they do not make the cavity themselves, and the same cavities are used for nesting for many years. In 2018, NCF biologists found that a cavity in a tree in Anamalai, wherein they saw a pair nesting 28 years ago, was still being used. “Big trees and cavities are very important for hornbills and such cavities with the right size are limited, given the size of these birds,” says Mr. Raman.

Large cavities are needed for the Great Hornbill to lay eggs as the females weigh up to 2.15 kg-3.35 kg as against the males that weigh up to 2.6 kg-3.4 kg. After the female enters the cavity, the entrance is partially sealed with droppings, with an opening left for her to receive food brought by the male. The female also moults her flight feathers and tail feathers before the eggs, normally two, are laid. The female comes out a few days before the chicks fledge, and the nesting cycle lasts 102-140 days.

Large trees with cavities that are repeatedly used by the hornbills for nesting remain protected in the forests and private forests or plantations in places like the Valparai plateau, says an official of the Forest Department. In the ATR that encompasses the Valparai plateau, the Department has identified places of nesting. “In the Anamalais, tea and coffee plantations are protecting large nesting trees. This can be replicated in other areas. The government’s initiative proposes to recognise such stewards as ‘Hornbill Protectors’, which will hopefully increase public support and involvement in conservation efforts State-wide,” says Mr. Raman.

Local tribal communities can be engaged to protect the hornbills, says Mr. Raman. “At least in the Anamalais, on the Tamil Nadu as well as Kerala sides, tribals, particularly Kadars, are monitoring the hornbills and their nesting. The local communities can be involved in conservation in other parts of Tamil Nadu too.”