A Fleeting Symphony: Grassland Birds of the Brahmaputra Plains
Photo StoryPublished : Feb 06, 2024Updated : May 09, 2024
The unique constantly changing grassland ecosystem in the plains of Assam host some highly threatened and unique bird species
Text by: Bhavya Iyer
Photos by: Dhritiman Mukherjee
The unique constantly changing grassland ecosystem in the plains of Assam host some highly threatened and unique bird species
The Brahmaputra, with an average width of 5.4 kilometres and swelling to over 30 kilometres in parts during the monsoon, thunders down from the Kailash mountain range, entering India near Gelling village in Arunachal Pradesh. The vast river, called Yarlung Tsangpo (in China), becomes Siang when it crosses into Arunachal, Dihang, as it descends to the plains. Merging with the Dibang and Lohit rivers, it finally becomes the Brahmaputra once it hits Assam’s Sadia district and forms a thousand-fold braided channel.
Millions of cusecs of meandering waters bring tonnes of sediment that make a fertile alluvial floodplain. The river creates a living, breathing, ever-shifting landscape as it courses through Arunachal, Assam, and Bangladesh, forming temporary islands, grassland habitats, and homes for countless creatures, great and small.
In the floodplains of the river, a unique grassland ecosystem arises. These grasslands host charismatic megafauna such as herbivores and tigers, but also some highly threatened and unique birds, including the Bengal florican and the black-breasted parrotbill. With annual floods constantly modifying the landscape, creating and destroying river islands (or chaporis), the species composition changes constantly.
In 1998, BirdLife International published a book, Endemic Bird Areas of the World: Priorities for Biodiversity Conservation, in which the Assam Plains Endemic Bird Area was delineated. The book, written by Alison J. Stattersfield and her team, also identified three restricted-range species in this region — the Manipur bush quail, the black-throated parrotbill, and the marsh babbler. The high diversity of grassland birds in this region is likely a function of the diversity of habitats, with some species preferring short grasslands, others hiding in tall wet grasses, and some even preferring short, grazed grasses where cattle roam. The ever-changing character of the riparian habitats of Brahmaputra enables this diversity of habitats.
The recent State of India’s Birds 2023 (SoIB) report highlights the grave threat to grassland birds in particular, with grassland specialists declining by more than 50 per cent and birds that live in other Open Natural Ecosystems (ONEs) also seeing a steep decline. Several of these threatened birds are native to the Brahmaputra floodplains and are regarded as “Species of High Conservation Priority”, according to SoIB. Many of these birds are insectivorous. The SoIB report found that insectivorous birds, among others, are declining in India. While this decline has been attributed to pesticide use globally, studies on the cause of this decline in India are not available.
Among the most renowned and yet threatened grassland birds is the critically endangered (1) Bengal florican (Houbaropsis bengalensis), whose numbers, worryingly, continue to decline. Projects are ongoing to survey and conserve the species and its habitat. According to ornithologist Dr Rahmani’s report in 2016, Roing in Arunachal Pradesh (2) has privately owned grasslands famous for florican sightings. Bengal florican females (3) are buff, unlike the showy, dark-coloured males with white wings. Their hue and reticent behaviour help them camouflage well. The females are much harder to spot and count for an accurate census, as unlike males, they do not perform aerial displays. (4) Males perform courtship displays during the breeding season, puffing up their feathers and leaping about the tall grasses to attract mates. Males are highly territorial. The species prefers moderately tall grasslands under a metre in height, particularly Imperata cylindrica grass.
Parrotbills are long-tailed, grassland or reedbed-living passerines of the fascinatingly named genus Paradoxornis, or “bird of paradox”. Ornithologist John Gould probably gave them this name because of their babbler-like appearance but parrot-like bill. Black-breasted parrotbills (Paradoxornis flavirostris) are designated “Vulnerable” by the IUCN and are a species of high conservation priority. They use their large bills to crack open nuts and seeds and also feed on grass stems, shoots, and insect larvae. The species is restricted to “nal” grasslands in Assam, comprised of Phragmites karka and Arundo donox grasses. Local communities extensively harvest these grasses, so it is important to ensure sufficient regeneration of the grasslands to preserve the species’ habitat.
Thanks to conservation efforts, the Amur falcon (Falco amurensis) has become well-known in recent years, particularly in Nagaland, where they congregate in huge numbers during their annual migration. This migratory raptor is also spotted in parts of Assam, including the Brahmaputra floodplains, usually during October to November, when they pass Northeast India en route to their wintering grounds in southern Africa. Raptors like the Amur falcon, being higher up in the food chain, are threatened by the biomagnification of toxic chemicals in the food chain (i.e., certain chemicals, ingested by prey species in small amounts, build up to deadly levels in carnivorous species such as these raptors).
Easy to confuse for a barn owl, eastern grass owls (Tyto longimembris) are rare on the Indian subcontinent, though their range is global and extends to Australia. They are specialised rodent hunters but also feed on small ground-dwelling birds, reptiles, and amphibians. Little is known about the species, but they prefer grasslands and open habitats in which they hunt like harriers, hovering and gliding.
(1) The west Himalayan bush warbler (Locustella kashmirensis) is a little-known species typifying the term “little brown job”, the affectionate, informal name given to those small, non-descript birds that even veteran birders can be hard-pressed to tell apart. The eBird description of this species states that it is best told apart from the similar-looking spotted bush warbler by its range and call. The west Himalayan bush warbler inhabits alpine scrub in the Himalayas in summer, migrating to the plains in winter. It is primarily insectivorous, like the strikingly coloured (2) yellow-bellied prinia (Prinia flaviventris), which has a quick call made up of a series of distinct twitters.
The chestnut-capped babbler’s bright orange cap resembles a head of henna-dyed hair. Despite its bright red eyes and white throat, these birds blend easily into their habitat of tall grass, reedbeds, and scrub. They move in noisy flocks and have a distinct metallic call.
Almost parrotbill-like in appearance, Jerdon’s babbler is a reclusive grassland bird that prefers tall, wet grasslands. Its golden ‘spectacles’ are an identifying feature. It can be found across a wide fragmented range through Pakistan, India, Nepal, Bangladesh and Myanmar.
(1) The swamp grass babbler (Laticilla cinerascens), also called the swamp prinia (though prinia-like in appearance, it is a babbler), is an endangered grassland species given little conservation attention. It prefers tall grass habitats, like elephant grass. The SoIB has classified it as a species of highest conservation priority due to its restricted range (confined to the Brahmaputra floodplains) and the lack of information on whether the species is declining or increasing. (2 & 3) The marsh babbler (Pellorneum palustre) is a ground-dwelling babbler that prefers seasonally inundated grasslands and marshes. Endemic to the Brahmaputra floodplain grasslands, it is difficult to observe and is known from only a few sites in Assam and Arunachal.
The swamp francolin or swamp partridge (Ortygornis gularis), designated “Vulnerable” by the IUCN, is the largest francolin on the Indian subcontinent. This pheasant’s call consists of a series of short, sharp cries. Females and males are believed to be monogamous and look mostly alike. Males are territorial and have spurs they use to fend off competitors.
Jerdon’s bushchat (1 is a female, 2 is a male) is a lowland and hill species, preferring open areas and medium-height grasses. It forages like most chats and will pick a prominent perch from where it flies out to capture flying insects. This species is a “habitat specialist” that is very picky about where it resides.
Grassland birds are plagued by multiple threats, including a decline in insect prey, pesticide residue, loss of grassland habitat to development and agriculture, and the damming of rivers impacting natural flooding regimes, sediment flow, and thus island formation.
The Brahmaputra floodplain grasslands face these threats as well as burning and collection of grasses, encroachment, and uncontrolled grazing, all of which negatively impact grass regeneration. With the sorry state of grasslands and other ONEs in the country – ONEs made up over 70% of the land marked as “wasteland” in the Wasteland Atlas of India 2019 — conserving these habitats and the unique species that call them home is of prime importance. The stunning array of endemic birds found in the grasslands of the Brahmaputra are almost overlooked when it comes to ecotourism and conservation efforts, cast in the shadow of charismatic megafauna such as tigers, elephants, and rhinos. However, with the increasing popularity of birdwatching and photography, there is hope that these wonderful and diverse species will soon get the attention they deserve.
About the contributors
Bhavya Iyer
has itchy feet that take her in search of wild landscapes, good food, and dark coffee. An alumnus of the Wildlife Institute of India, she has an interest in carnivore ecology and environmental policy.
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.
