Words and picture by Rick Beven.

If you had to make a list of the top ten places in the world to see birds the Koshi Tappu Wildlife Reserve in East Nepal would be in it, alongside Cota de Doñana in Spain, Lake Naivasha in Kenya and Dungeness in the UK. Over 460 species of birds, half of Nepal’s total species, have been recorded in the reserve.

The Koshi, one of Nepal’s largest rivers, runs through the reserve. Seven rivers merge upstream to form it: the Tama Koshi, Bhote Koshi, Dudh Koshi, Sun Koshi, and the Barun, Arun, and Tamor Rivers. A vast flow of water surges out of the hills into the terai plains of Sunsari and Saptari and then debouches into the Indian state of Bihar. When the river bursts its embankments, as it did in 2008, vast areas of the eastern Terai and Bihar are inundated.

At its widest point, the Koshi River is 10 kilometres across and forms many channels divided by constantly shifting sandbars. The tall white grass that grows on the sandbanks, and the marshes, ponds and riverine forest next to the river, are home to thousands of birds, particularly large populations of egrets, herons and storks. It is Nepal’s only Ramsar wetland site and also holds globally threatened populations of Asiatic Wild Buffalo, Gangetic Dolphins and Fishing Cats.

We started our day at Koshi Camp, a small tented camp for birdwatchers, and managed to see a baker’s dozen of different birds over our cups of tea. A blue tailed bee eater, a local winter migrant, was preening its wings with its scythe like beak perched on a tree beside the tented accommodation. Next to it was a Chestnut-tailed Starling. Smaller green bee-eaters were hawking after insects around the lodge. A spotted owl, its head hunched into its wings, like Owl in Winnie the Pooh, was sleeping in the tree next to the restaurant. A cinnamon bittern took off across the lotus ponds. A common kingfisher sat in solitary orange splendour in the middle of the pond. Great egrets and little cormorants flew overhead, returning to the heronry by the river.

A short walk before breakfast along the Koshi embankment produced a good bag of riverine birds. A brown-capped pygmy woodpecker, Nepal’s smallest woodpecker and a first for me, probed for insects at the top of a dead tree. We disturbed a pair of black-rumped flamebacks, who flew off in a flash of gold. A female Fulvous-breasted Woodpecker was spotted in another dead tree. We saw a jungle owlet, differentiated from the spotted owlet by its beautiful brown barring on its breast, sunning itself on a tree.

A Grey-Backed Shrike, a winter migrant from Tibet, sat on lookout on the top of a thorn bush. It will winter in the Terai before returning to Tibet in the spring. Another winter visitor, an invisible greenish warbler was heard calling in the undergrowth by the road.

By a tributary of the Koshi we spotted a group of six arna or wild buffaloes lying chewing the cud on a sandbank on the other side of the river. Wild buffaloes have the largest horns of any bovine and their horns looked spectacularly impressive through my binoculars. Asiatic Wild Buffaloes can be differentiated from their domestic cousins by their large horns, white forelegs and the white tips of their tails.

After a leisurely breakfast of masalla omelettes and tea we set off in a landrover to meet up with our boat, an inflatable dingy, further upstream. Casting off, we drifted down one of the main channels of the Koshi, rowed by a local fisherman, bird watching as we meandered down the river.

The river here was at least kilometre across and bordered by an endless expanse of white kansh grass. The flow was strong and full of eddies and gurgles. We passed a little heron hunched at the side of the river, its baleful yellow eye, black crest and eye-stripe giving it the demeanour of an over-worked clerk. A river turtle slipped into the water with a loud plop.

We stopped on a sand bank to look at sand larks and a group of five lesser sand plovers, rare visitors from the Tibetan plateau and Kirghiz Steppes on their way to winter on the Indian coast. Further downstream we flighted a flock of common teal, winter visitors from Russia, and some of the thousands of ducks that will over-winter on the vast expanse of water behind the Koshi barrage.

Drifting down the river we saw a bird with long, slim wings flying slowly above the grass. It was the first pied harrier of the season, a beautiful adult male, its black and white under-body and wings contrasting wonderfully with the white grassland it was quartering over. He will stay here in his winter quarters at Koshi Tappu until April when he returns to his summer breeding grounds in Central Asia.