Once upon a time,” begins Ugyen Drukpa — UD as he likes to be called — in his usual measured tones. I am all attention for yet another story. We’ve spent five days in Bhutan and with a guide like UD, the lore flows much faster than my brain can process.

“Once upon a time,’’ repeats UD as he embarks on his tale, “there was a snake and a boar. ‘Let us race to the Gangteng Monastery,’ said the snake. ‘If I win, farmers will grow rice on their land. If you do, they will grow potatoes.’

“The snake had a meandering gait. Naturally, the boar won the race. So, potatoes are grown in the Phobjikha Valley. It’s difficult to grow rice,” UD continues. “Those rivers that you see through your viewfinder are Nakay Chhu and Gay Chhu, representing the snake and the boar,’’ he finishes with a flourishing sweep of his hand.

In the watered-down light of dusk, the rivers are thin bands of silver streaking across a vast marshland. At 9,600ft, Phobjikha in Wangdue district is a bowl-contoured glacial valley on the western slopes of the Black Mountain range. It borders the Jigme Singye Wangchuk National Park, home to Himalayan black bear, leopards and red foxes. Phobjikha is the largest of all wetlands in Bhutan and the most significant.

Significant, for every winter the valley becomes a nesting ground for the endangered Grus nigricollis. Or, in the common tourist’s language, black-necked cranes. The locals call them thrung thrung karmo.

In early November, the cranes migrate from the Qinghai Tibetan plateau to Phobjikha, Gyetsa and Bomdeling in Bhutan. In Arunachal Pradesh, these visitors might find themselves a part of the residents’ daily meal. But in Bhutan, their arrival is considered a good omen especially since each flock of cranes circles over the Gangteng Monastery before settling in the marshlands. They circle the monastery once more before leaving the valley in March.

The Royal Society for Protection of Nature (RSPN) has a Black-Necked Crane Visitor Centre at Phobjikha. “November 6: the first batch of cranes has arrived!” says the scrawl on a white board inside. The count at present is 41. More than 500 cranes had visited the year before. Another board offers a rough sketch of the shallow ponds that are a favourite with the birds. There are hidden cameras around these ponds. Inhabitants and visitors are instructed to give a very wide berth to these nesting areas.

On the Wings of a Prayer, an informative video by Dasho Paljor Dorji, narrates how the cranes are now a part of Bhutan’s folklore and songs. Even the mating dance of the cranes has been adopted as the victory dance in archery contests, Bhutan’s most popular sport.

The centre’s powerful telescopes magnify some 20 birds foraging right then on the marshlands. But the cranes are too far away, and it’s impossible to make out their features in the constantly bobbing black-and-white bodies. They’re polishing off fallen grain, tubers and insects like there’s no tomorrow.

For the 4,700 residents of Phobjikha, however, ‘tomorrow’ is a big day. The next day, they turn up at the Gangteng Sa-Ngag Choeling Monastery in their best attire for the Annual Black-Necked Crane Festival.

True to its name, the Gangteng (gang teng: hill top) Monastery sits atop a hill at 9,840ft, representing the Tibetan style of architecture. It’s the largest Nyingmapa monastery in Bhutan, founded in 1613 by Gyalse Pema Thinley, the grandson of Tertön (someone who has discovered hidden Buddhist treasures) Pema Lingpa.

In the monastery courtyard, adults and schoolchildren dance in colourful costumes and masks. They are often and merrily  interrupted by furry dogs and atsaras — clowns wearing red masks. In a unique dance, the children dress like cranes and imitate their movements. If this isn’t the best way to teach conservation to the next generation, we don’t know of a better one.

There is a short, untimely shower. Then, fortified with handfuls of roasted rice sprinkled over hot butter tea, the dancers continue. For us, though, it’s time to go on the Gangteng Nature Trail.

The trail winds past thickets of dwarf bamboo, the log cabins of Semchubara village, and gurgling rivulets. Fallen pine needles with their smooth, round shapes lay an auburn, slippery, carpet underfoot. The monotony of tall pines covered in gossamer veils of lichen is broken by rhododendrons, birch, maple, fir and the occasional hemlock. A couple of white wagtails sun themselves on a makeshift wooden bridge.

The valley is snowbound in winter and residents shift to their winter homes in Wangdue Phodrang. The cranes stay on, braving blizzards to nest with their life-long mates.

Even through my feather jacket, the cold wind traces my spine. We, too, have braved the cold, survived an electrical short-circuit fire right under our hotel room. So, we’ve done without the geyser, room lights and electric kettle for all of our 48 hours in the valley.

Were these 41 cranes, these dots bobbing up and down in the distant marshes and leaping gracefully in the air worth the journey? As a nature lover, it simply uplifts my soul to know that in a world exploding with humans, there is at least one valley where a few hundred birds may dance with abandon.