Guwahati: Tucked away in the northern folds of Sikkim, shielded by the mighty Kanchenjunga and cradled between the Teesta and Talung Rivers, lies Dzongu — a sacred, almost mythical homeland of the indigenous Lepcha people. Here, amidst dense forests, cascading streams, and a breathtaking mosaic of subtropical to alpine landscapes, flourishes a treasure trove of winged wonders: butterflies.
Between 2016 and 2024, an extensive field study by Sonam Wangchuk Lepcha, a butterfly enthusiast from Dzongu, and biodiversity researcher Monish Kumar Thapa revealed an astonishing 420 species of butterflies fluttering across this remote valley.
Representing six families and 187 genera, this extraordinary diversity accounts for more than 60% of all butterfly species recorded in Sikkim — a stunning achievement for an area spanning just 78 square kilometres. Their findings were recently published in the Journal of Threatened Taxa.
The Nymphalidae, often called the “brush-footed butterflies,” reigned supreme with 165 species, followed by the vibrant Lycaenidae (92 species) and the swift Hesperiidae skippers (84 species). Rare gems like the elusive Teinopalpus imperialis — the resplendent Kaiser-i-Hind — and Papilio krishna, the majestic Krishna Peacock, were also recorded.
“After 10 years of walking through forests, climbing hills, crossing rivers, and spending countless days and nights under the open sky, I am thrilled and proud to share that I have recorded 420 species of butterflies from Dzongu,” said butterfly enthusiast Sonam Wangchuk Lepcha.
“This is not just my achievement. It’s a moment of pride for everyone from Dzongu. Our home, rich in forests, culture, and traditions, has now been recognised as one of the world’s most important places for biodiversity. While Sikkim is already a global hotspot for butterflies, what fills me with even more pride is that over 60.95% of all butterflies found in Sikkim are from Dzongu itself,” he added.
Dzongu’s almost year-round sub-tropical hill forests, lush and alive, nurtured the highest butterfly diversity, with nearly 395 species recorded. In contrast, the misty sub-alpine forests near the icy peaks were home to only 13 hardy species.
Sonam’s journey was not without hardship.
“There were days when I walked from morning to evening without seeing a single butterfly,” he recalled.
“Some days, heavy rains, landslides, or leeches made it difficult to continue. I’ve got lost in thick forests, crossed dangerous rivers, and waited for hours under trees — all just to catch a glimpse of a butterfly. People often laughed, wondering why I spent so much time chasing butterflies. But deep inside, I knew I was doing something meaningful — something for Dzongu, for my people, and for the future of our biodiversity.”
Among Dzongu’s most celebrated natural treasures is Bassarona durga, the Himalayan Blue Duke — now the official state butterfly of Sikkim — often seen gliding gracefully along river belts and village trails. Another gem, Zographetus dzonguensis, the Chocolate-bordered Flutterer, was first discovered here, putting Dzongu firmly on the global map of butterfly discoveries.
What makes Dzongu so uniquely rich? The valley’s natural isolation, coupled with a staggering elevation range from 700 to 6,000 meters, has created a living laboratory where tropical, temperate, and alpine species coexist within astonishingly short distances. Ancient forests, traditional Lepcha land stewardship, and the protective presence of the Kanchenjunga Biosphere Reserve further shield this fragile paradise.
The survival of Dzongu’s butterflies, the study notes, is closely tied to the availability of nectar plants, host plants, and pristine water resources that encourage mud-puddling — a behaviour where butterflies gather to sip essential minerals. Water bodies like Tungkyong Dho (Lake) — a designated Biodiversity Heritage Site — Lingthem Kyong, Talung Wetland, and the rivers Rungyoung and Narim Uung Kyong, among others, serve as lifelines for butterfly populations.
“Today, when I watch butterflies dance over the fields and rivers of Dzongu, I feel a connection — as if they are saying ‘thank you’ too,” Sonam said.
“Each butterfly I discovered revealed a part of Dzongu’s soul — a soul that deserves to be known and cherished by the world.”
Sonam also extends heartfelt thanks to his team members from the Butterfly Society of Sikkim – TPCF — Mingdup Lepcha, Janukit Lepcha, Dawa Lepcha, Lhendup Lepcha, Puja Rai, Ukee Bhutia, and Lakpa Tshering Lepcha — for standing beside him through this decade-long journey. He thanks his seniors, Nosang M. Limboo and Sonam Pintso Sherpa, who have always guided and encouraged him and believed in him.
“But I believe this is just the beginning. Many more beautiful butterflies are waiting to be discovered in the hidden corners of our hills. I promise to keep walking, keep exploring, and keep working for our butterflies and our land’s biodiversity,” he said.
“Every butterfly I saw gave me new hope. Each colourful wing reminded me to never give up on my dream. Today, I feel that all the pain, sweat, and struggles were worth it.”
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