By Anoop NR
The Moyar River valley
About 30 km east of Udagamandalam (Ooty) in the Nilgiri district of Tamil Nadu resides a dramatic landscape of the Western Ghats – the Moyar Valley. This valley is an ecologically outstanding region of the Western Ghats and home to a variety of flora and fauna. Nestled in the midst of four plateaus – the majestic Nilgiri plateau in the southwest, Sigur and Mysore plateau in the west-north, the Thalamalai plateau in the north-east and towards the east, the valley merges with the Coimbatore plains.
The region derives its name from the Moyar River that drains the area. The name Moyar has been originated from the Tamil words “Moyam” or “Maya” meaning ‘which disappears suddenly,’ and “aar” meaning “river”. On its way, the Moyar River flows through the wet Wayanad plateau and then enters the Moyar Gorge which is a remarkable geographical formation. This 2.5 billion-year-old gorge has received a lot of geological attention. After its journey through the gorge for more than 25 km, the river enters the Moyar valley and later joins the Bhavanisagar Reservoir in the southeast corner of Nilgiri plateau. With best preserved riparian forests flowing through the rain shadow regions in the Western Ghats, it may be difficult to find a perennial river like the Moyar. The valley is home to various indigenous tribal communities including Irulas and Valayas. People here are mostly agropastoralists and gatherers of non-timber forest produce.
The valley is part of the Nilgiri Biosphere Reserve (NBR) which is one of the largest contiguous stretches of forest in the country that has exceptional importance for biodiversity conservation. This landscape harbours the single largest breeding population of tiger, Asian elephants and a significant population of endangered vultures, hyenas, blackbucks, mahseers and myriads of other life forms. Besides the rich biological and cultural diversity, the landscape has also been famous across the country due to the influence of the brigand “Veerappan.” Most of the people I met in the valley had many stories to tell about him, both good and bad! My experience with this valley started when I carried out my Master’s dissertation work on understanding the distribution and nest-site selection of diurnal birds of prey in the Valley.
Silent predators of the Moyar valley
Raptors or the birds of prey are a fascinating group of birds belonging to the avian order Accipitriformes which includes hawks, eagles, kites, buzzards, harriers, falcons, vultures and their relatives. While raptors are adapted to feed on other animals, a few raptors feed on vegetables and fruits. These formidable predators situated at the top of biological food chains play a vital role in structuring regional and global ecosystems. Several of them are known for their long-distance migration. Since they are dependent on the abundance of a variety of prey items, the presence of diverse raptors indicates the richness of the ecosystem itself.
Raptors are considered a difficult group of birds to study in the field because of the high variability in their plumage and the difficulty in finding them as they are less abundant. For my study, I used vantage-point surveys to identify and count them. This survey method is one of the standard types to identify and count soaring raptors. To perform this survey efficiently, one has to identify and position themselves in elevated locations of the landscape. The process of climbing up to the vantage points in the valley permitted beautiful glimpses of the Moyar valley even while being captivated by the spectacular flight of raptors over green canopies.
Among all the vantage points, Alliranikotai was one of the most mesmerising sites I visited and developed a special bond with this place. Alliranikotai is an emergent rock hill (extension of Nilgiri plateau) located in the west of Thengumarahada village. This hill along with numerous cliffs and exposed rocks gives the view of the entire valley. It is an astounding scene that different varieties of raptors including large flocks of vultures come from various parts of the valley to Alliranikoatai in the morning and use the thermal lift (rising mass of air formed over the land after heating up from sunlight) generated by the rock to glide up. I was lucky to sight “Merlin” a rare and handsome falcon from the rocky cliffs of this hill.
In the short span of my five-month study, I recorded thirty-two species of raptors including resident and migrants of which many of them are threatened and rare. The valley’s high species richness is associated with its diverse habitat types and altitudinal gradients across the region. In addition to all the natural vegetation types of the Western Ghats, we can find plantations of different tropical cash crop and reservoirs within a 50 km radius of the valley. The shape and location of the valley which is tunnel-like and sandwiched between higher plateaus probably have a good flow of thermals which attract raptors. Hence it is likely that the raptors use this valley for their north-south movement across the Nilgiri-BR hills block in the peninsula, making this a vital raptor passageway in the Western Ghats.
The Bhavanisagar Reservoir also attracts a large number of resident and migrant wetland birds. These birds ensure food source for large raptors that depend on wetlands such as Aquila eagles. Similarly, the rich riparian forest and high fish stock provide the best habitat for fishing eagles.
About the Author:
Anoop NR Joined ATREE PhD program in 2015. For his PhD, he is studying the landscape changes and its impact on Asian elephants in Wayanad plateau of the Nilgiri landscape, Western Ghats. He is fascinated in observing and spending time in the wild especially in the wet evergreen forests. He also enjoys playing football.