Speaking to Express JaferPalot, who heads the team conducting the butterfly census organised jointly by the Forest Department and Malabar Natural History Society in the sanctuary, stated that butterfly migration in the region is usually witnessed in December and January. "As the temperature in high altitudes will go down during these months, butterflies will move to lower altitudes en masse during the season. The migration takes place during 10am to 2pm " he said. "Of the 327 butterfly species in the state, 252 are found in the sanctuary. Species such as Malabar Rose, Malabar Banded Peacock, Malabar Banded Swallow Tail, Malabar Tree Nymph, Canara Oak Blue and Southern Oak leaf are endemic to the region," he said.

"The census was conducted through transit line method. Members participating in the census count the number of butterfly that pass through various migratory paths within five minutes. There were times when 45,000 butterfly were counted in a minute.

That means around 28 lakh butterflies migrate during two months. However, the number has gone down in the recent past," , he opined.

"There could be various reasons for this. The increase in pressure in the migratory areas is one of them. Delayed rain can also hamper the movement of butterflies as the migration will start only after the withdrawal of the northeast monsoon," Jafer said. He further said that most of the butterflies migrate from west to east along the Cheenkaniriver.

"The butterflies mud puddle to absorb the minerals from the sand along the river. However, sand mining, excess usage of detergents and human interference seems to be affecting the butterflies in these region. But, no study has been conducted to confirm this," he said.

This year the team has extended the census to Kottiyoor wildlife sanctuary as well.