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Great hornbills adapting to life in human habitations of southern Western Ghats

According to a latest study by the Nature Conservation Foundation on the Great Hornbill, these large-bodied birds are seemingly able to adapt to human-modified landscapes such as tea and coffee plantations.

bengaluru Updated: Oct 04, 2018 08:55 IST
Sibi Arasu
Sibi Arasu
Hindustan Times, Bengaluru
Great hornbill,Western Ghat,Nature Conservation Foundation
Great Hornbill is fondly referred to as ‘farmers of the forest’ because of the great distances to which they help disperse seeds.(HT File Photo)

The undulating plateaus of Valparai in the southern Western Ghats are a mosaic of commercial tea and coffee plantations with remnants of the native shola-grassland ecosystems interspersed in between. Despite expansive plantations, the region is rich in biodiversity. Elephant families are a common sight and the discerning observer can spot the endangered Nilgiri Tahr as well. Another popular resident of these mountains is the Great Hornbill, fondly referred to as the ‘farmers of the forest’ because of the great distances to which they help disperse seeds.

“There are times when you can see 70-100 Great Hornbills gathered together during the non-breeding season. They are in such great numbers because they are largely frugivorous and they track fruiting trees, particularly large, fruiting fig trees. It’s truly inspiring to see and hear them,” says Divya Mudappa, senior scientist at Nature Conservation Foundation (NCF) and a resident of Valparai for nearly two decades.

“Their distinctive kawks and grunts as well as the loud whooshing noises that their wings make while in flight are hard to ignore. One of our colleagues actually thought he was in Jurassic world and is being attacked by them when he heard them first.”

Adapting to survive

According to the NCF’s latest study on the Great Hornbill, these large-bodied birds are seemingly able to adapt to human-modified landscapes such as tea and coffee plantations. The findings are especially reassuring since, more often than not, it is the adverse impact of the Anthropocene on ecology and biodiversity that is talked about. (The Anthropocene defines Earth’s most recent geologic time period as being human-influenced, or anthropogenic, based on overwhelming global evidence that atmospheric, geologic, hydrologic, biospheric and other earth system processes are now altered by humans.)

Pooja Pawar, lead author of the study says, “We have found that hornbills are using plantations in critical times such as during nesting. This is important because a flagship species such as this is trying to survive and make use of whatever resources are available to it.”

The 220 sq.km Valparai plateau, much like the rest of the Ghats, have witnessed tremendous loss of mature tropical forests to agricultural expansion. Pawar adds, “The plateau is in close proximity to natural forests and also retains 40 rainforest fragments of varying sizes. These fragments have more food plants for the birds than their neighbouring coffee plantations. I believe this proximity acts as a stepping stone for hornbills to survive in such heavily managed plantations.”

In their paper published in the research journal, Ornithological Science, last month, the researchers state, “In the human-modified landscape of the Anamalai Hills, India (of which Valparai is a part of), we compared the breeding biology and nesting behaviour of Great Hornbills in contiguous rainforest and in modified habitat consisting of coffee plantations and rainforest fragments. Hornbills in the modified habitat of coffee plantations used non-native tree species for nesting and foraging, indicating their adaptability to modified landscapes.”

For their study, the researchers observed eight nests, three in contiguous rainforests and five in modified habitats consisting of coffee plantations and rainforest fragments. The nesting cycle of the birds observed lasted about four months and they found it was similar in both habitats. They found that each of the Great Hornbill was in a different species of tree. Seven were in native trees, and one was in a non-native Silver Oak tree. All nest cavities were in the main trunks of the tree. The researchers found that the Great Hornbill, in spite of having specialised nesting and foraging requirements, nested successfully in the plantations.

P Balasubramanian, senior principal scientist at the Salim Ali Centre for Ornithology and Natural History, Coimbatore, concurs with the results of Pawar’s work. Balasubramanian, a veteran in the field, has conducted ecological studies on four species of hornbills namely the Great Hornbill, Malabar Pied Hornbill, Malabar Grey Hornbill and Indian Grey Hornbill. He says, “Irrespective of whether the habitat is natural or human-modified, Great Hornbills would be ‘happy’ if tall trees with huge girth (for nesting) and fig trees (for foraging) are available in the forested environment.”

A helping hand

While the Great Hornbills are trying to make the best of what is available to them, support from plantation owners and their interest in providing a ‘home’ for the birds within their properties is also helping. Pawar says, “Plantations owners are also proud of these birds nesting in their properties and are becoming ‘hornbill friendly’ in many cases.”

In the paper, the researchers have also pointed out that the Valparai coffee plantations harboured many hornbill food plants. The hornbills had also used non-native tree species for nesting and foraging.

First Published: Oct 04, 2018 08:55 IST