When mountains shed their jewels

One crisp Dec morning in 2000, during a routine visit to the Aralam forests, butterfly experts Jaffer Palot and V C Balakrishnan witnessed a breathtaking sight—an endless stream of Common Albatross butterflies (Appias albina) gliding along the forest clearing carved by Cheenkanni River, in shimmering white and yellow like drifting petals.

Little did they know the fleeting spectacle would spark a 25-year journey of observation and documentation by butterfly enthusiasts and researchers, revealing Aralam’s extraordinary butterfly diversity.

What began as a moment of wonder evolved into a sustained scientific effort under the Malabar Natural History Society (MNHS), which has conducted annual butterfly surveys for the past 25 years. This work helped establish Aralam as Kerala’s butterfly capital, now set to be renamed Aralam Butterfly Sanctuary—India’s first official butterfly sanctuary.

The 55 sq. km. Aralam Wildlife Sanctuary established in 1984 and situated in the valley of Brahmagiri mountain ranges is the prime butterfly habitat of Kerala for good reason. Of the 327 species of butterflies found in Kerala, a staggering 266 speciesover 82%have been recorded here. Among them are 27 species endemic to the Western Ghats and six listed under Schedule I of the Indian Wildlife (Protection) Act.

Endemic species include the Travancore Evening Brown, Sahyadri Rosy Oak Blue, Malabar Rose, Malabar Banded Swallowtail, Malabar Banded Peacock, Shiva Sunbeam, Nilgiri Grass Yellow, Sahyadri Silver Royal, Kodagu Forest Hopper, Southern Spotted Ace, Nilgiri Plain Ace, Sahyadri Orange Ace, Sahyadri Banded Ace, and Sahyadri Albatross. Other significant species recorded are the Purple Spotted Flitter, Maculate Lancer, Black Angle, White-tipped Line Blue, Orchid Tit, Malabar Flash, Blue Nawab and Blue-banded Duffer.

“The range of forest habitats—from moist deciduous to semi-evergreen, evergreen, and shola grasslands— allows Aralam to support this incredible diversity,” says Jafer Palot, scientist with the Zoological Survey of India and MNHS member.

He explains that Aralam’s unique climate and forest gradient, from sea level to 1600 metres, supports diverse plant life, creating an ideal butterfly habitat. “Almost all forest types found in the state are present within the sanctuary,” he adds.

The most awe-inspiring event at Aralam is the annual butterfly migration. Each year from Dec to Feb, the sanctuary bursts with life as millions of exquisite butterflies, predominantly the Common Albatross, undertake an altitudinal migration, gliding downhill from the upper reaches of the forest. The phenomenon typically begins around 9.30am and lasts until about 2pm.

For the indigenous communities living around Aralam, the migration is not just biological—it’s cultural. Local tribal lore likens the migration to women heading to a wedding, dressed in shimmering white, gliding gracefully through the canopy corridor.

Aralam is also a key site for the annual Danaine butterfly migration to the Western Ghats from the Eastern Ghats and southern plains. During the 2013 survey, more than four lakh Danaine butterflies were recorded roosting near Pothanplavu.

“Though we’ve tracked the migration since 2001, many unknowns remain, including where these congregations are headed,” says Palot. Earlier, it was assumed the butterflies came from Coorg via Kottiyoor and moved to Wayanad en route to the Nilgiris. “Now we know it’s an altitudinal migration from higher reaches above Meenmutti Falls. Still, we don’t know where they ultimately go, as Albatross butterflies are forest species and rarely leave forested areas.”

These butterflies likely originate from altitudes above Meenmutti Falls, where their host plant Drypetes—locally called Asthi maram—grows abundantly. As the population grows and nectar becomes scarce, a mass dispersal down the slopes is triggered.

“In a five-minute count this Jan, we recorded over 12,000 butterflies,” says Palot. “That translates to three to four lakh butterflies a day, and crores over the entire season.”

The Cheenkanni River and its streams play a critical role in this migration. The mineral-rich riverbanks allow butterflies to supplement their diet with essential nutrients like sodium, nitrogen, and amino acids—vital for flight and reproduction.

“Maintaining the riverbank’s integrity is crucial,” Palot says, warning that illegal sand mining threatens these habitats.

Aralam wildlife sanctuary warden G Pradeep says the butterfly diversity is a testament to its ecosystem integrity, as butterflies are indicator species and help with pollination.

“Renaming the area as a butterfly sanctuary will allow us to implement habitat management like removing invasive species and promoting biodiversity-friendly vegetation. Many larval host plants like Mullilam (Zanthoxylum rhetsa) are disappearing from non-forest areas,” he adds.
Environmentalists stress that addressing illegal sand mining along the Cheenkanni River is vital, as it threatens the sanctuary’s habitat and affects mud-puddling behavior of butterflies during migration.

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