Photo StoryPublished : Oct 15, 2024Updated : Oct 16, 2024
Uncovering the park’s secret residents, from magnificent hornbills to India’s only non-human ape, the hoolock gibbon
Text by: Tarun Menon
Photos by: Dhritiman Mukherjee
Uncovering the park’s secret residents, from magnificent hornbills to India’s only non-human ape, the hoolock gibbon
Some of the country’s most beautiful lowland tropical rainforests lie in the northeasternmost parts of India, at the border of Assam and Arunachal Pradesh. This region is also blessed (or cursed) with immense natural reserves like coal, oil, and abundant timber. Over centuries of mining, logging, and agricultural expansion (tea), very few patches and fragments of the original habitat remain. At around 231 sq km, Dehing Patkai National Park is one of the largest remnants, offering a peek into the disappearing world of mighty dipterocarps, ancient tree ferns, and elusive wildlife. Found on the banks of the Dihing River and the western foothills of the Patkai Hills, it was first notified as a wildlife sanctuary in 2004 and upgraded to a national park in 2021. One of the most well-known and important species in Dehing Patkai is the hollong tree (Dipterocarpus retusus), which has also been declared the state tree of Assam and Arunachal Pradesh. How the tree got its name has a very popular (although apocryphal) story attached to it, of which a version was narrated to me by an enthusiastic guide: when the British first explored the landscape and came across the tree, one of the surveyors bent over backwards trying to find the canopy and, amazed by the height, he exclaimed, “how long” which ended up evolving into “hollong”. IUCN classifies it as “endangered” because its population has declined by 50-70% over the last 300 years due to the land-use change and selective logging for timber. The hollong and the mekai tree (Shorea assamica) grow up to 50 m tall and form the dominant canopy layer in the landscape. These towering forests are thus home to a number of canopy dwellers, making the Dehing Patkai landscape one of the richest regions in the country for arboreal species like primates, squirrels, and a variety of other birds and reptiles.
Four species of charismatic hornbills live in these forests, of which the (1) oriental pied hornbill (Anthracoceros albirostris) is the most common. It is often seen outside the forest in adjoining rural areas and cultivation. On the other hand, (2) the brown hornbill (Anorrhinus austeni) sticks to primary, undisturbed forests and is significantly harder to see. Found mostly in southeast Asia with only the westernmost extent of its range inside India, Dehing Patkai National Park is one of the best places in the country to spot this bird.
Beneath the dense canopy where very little light reaches, some of the most outrageously vibrant birds skulk around in the dark. (1) The hooded pitta (Pitta sordida) is a mysterious bird that turns up in Dehing Patkai and other parts of the Himalayan foothills in the summer. Where this species migrates to in the winter is poorly known, possibly migrating long distances to peninsular Malaysia and Sumatra. (2) The red-headed trogon (Harpactes erythrocephalus) is a considerably more common bird, often seen perched somewhere below the canopy in parts of the forests that are cool and damp. (3) The grey-lored broadbill (Serilophus rubropygius) was recently split taxonomically from the silver-breasted broadbill (which was formerly its name) of Southeast Asia. Both females of the species have the eponymous silver breast band with slight variations in extent. The differentiating factor is the wing colouration and the colour of the lores (area between the eye and bill), yellow in the silver-breasted broadbill and grey in the grey-lored broadbill.
The two migratory kingfishers seen in Dehing Patkai are exceptionally colourful, albeit extremely rare. (1) The larger ruddy kingfisher (Halcyon coromanda) may look dull orange-brown, but in the sunlight, has a lilac sheen on its back and a bright azure rump in flight. (2) The tiny black-backed dwarf kingfisher (Ceyx erithaca), formerly (and more popularly) known as the oriental dwarf kingfisher, is an explosion of colour. Its back is not actually black but an iridescent deep blue. It has a bright red bill and brilliant pink-lilac crown with patches of blue on the neck and forehead, all of which make it a favourite among Indian bird photographers. Like the hooded pitta, both species are summer visitors to Dehing Patkai with relative uncertainty regarding where they go in the winter (perhaps somewhere between southern Thailand, Sumatra, and Java).
Spotting mammals in Dehing Patkai can be very challenging due to the dense vegetation. The orange-bellied Himalayan squirrel (Dremomys lokriah) is a shy yet common squirrel seen scurrying about in the branches overhead. During the day, they can be incredibly noisy when a cacophony of squirrels squeak from different parts of the forest, possibly advertising their territories. This species is endemic to the eastern Himalayas and the adjoining hills, where there is considerable variation in appearance, leading to eight subspecies, six of which are found in India.
Some of the quintessential tree-dwelling birds of this region are woodpeckers, which act as the engineers of the forest. They create nest cavities for themselves that are later used by a variety of other birds and mammals, such as squirrels. (1) The rufous woodpecker (Micropternus brachyurus), however, doesn’t offer this service, preferring to nest inside the nest of Crematogaster ants. (2) The diminutive white-browed piculet (Sasia ochracea), which forages very close to the ground, is also found in Dehing Patkai. It is generally a solitary species but will often join mixed-species flocks in the winter. In the summer, it has a strong affinity for bamboo, often using it for nesting.
The pale-capped pigeon (Columba punicea) is a rare and much sought-after species for birdwatchers visiting Dehing Patkai National Park. One of the best spots to see this bird is in the buffer zone of the national park at a salt lick surrounded by fruiting trees. Here, they are occasionally spotted in flocks of five to twenty either on the ground or devouring fruits in the tree. Some locals mention that they have seen flocks foraging on rice fields adjoining the park. Globally, the bird is classified as “vulnerable” by the IUCN because its population is estimated to be below 10,000 and declining due to habitat loss and hunting.
Any visit to Dehing Patkai is incomplete without the loud echoing howls of duetting hoolock gibbons (Hoolock hoolock). More often heard than seen, these shy primates prefer to stay hidden in the canopy. Only after craning your neck and squinting your eyes will you manage to catch a glimpse of them. The western hoolock gibbon is the only non-human species of ape found in India and lives in nuclear families (as seen in the picture above). Males are black with white eyebrows, while females are beige with a white mask. Families consist of up to three children, born about two-and-a-half years apart. Interestingly, babies are born white, become brown in a couple of months, turn black (with eyebrows) around their first birthday, and when they reach sexual maturity at around eight years, they either stay black if male or revert to beige if female.
About the contributors
Tarun Menon
is an avid naturalist, birdwatcher and a PhD student at the Indian Institute of Science. His interests lie in understanding the behaviour and adaptations of mountain birds.
is one of India's most prolific wildlife and conservation photographers. His work has been featured in leading publications. He is also a RoundGlass Ambassador, and an RBS Earth Hero awardee.
