Aralam Wildlife Sanctuary witness huge Danaine butterfly roost as migration season kicks off

Aralam(Kannur): Marking the beginning of yet another season of butterfly migration, Aralam Wildlife Sanctuary in Kannur District of Kerala witnessed a large congregation of  Dark blue tiger, Common crow and Double banded crow butterflies of Daniane family at Pothanplavu area of the sanctuary during the second week of January. 

According to sources in the Malabar Natural History Society, a Calicut based nature organization which conducts a routine butterfly survey at the sanctuary with the support of Kerala Forests and Wild Life Department to observe and document migration, there could be more than 3 lakh butterflies roosting at Pothanplavu area only. During the survey, at least two similar roosts were reported at different places in the sanctuary. According to sources, the roosting flies could be a part of large flocks of butterflies which were reported migrating from Nadukani plains of the Nilambur forest during last week.

Dark Blue Tiger (Tirumala septentrionis) butterflies roosting at Aralam WLS

A roost or congregation is a group of butterflies which perch on trees or plants, often with limited physical activities and with almost no feeding. Usually butterflies do not shift their roosting sites every year, so roosts were earlier observed in Aralam almost in the same places during migration season.

 “During a roost, migrating butterflies live through weeks with limited or no activity like feeding.” says Dr. Jafer Palot who has conducted studies about the butterfly migration in the Kerala part of Western Ghats. “However, we have observed mating behavior among roosting butterflies”, he said during a lecture to the team members who took part in the survey.

Butterfly roost at Aralam WLS: Video Clip

Common Albatross migration at Aralam Wild life Sanctuary

The survey teams have also reported that the migration rates of Albatross butterflies from the sanctuary was more this year during the survey days, unlike last year.   According to a press release issued by MNHS, a peak point of Common Albatross Migration was observed this year with a maximum count of more than 500 butterflies in 5 minutes time, all along the Cheenganni River of the Park. Last year, the rate was very minimal, mainly owing to the shrinking of mud puddling sites, according to sources.

According to researchers and volunteers who took part in the survey, groups of migrating common albatross butterflies were often followed by Bluebottle, Great Orange Tip and Painted Saw-tooth butterflies.

The butterfly migration here is usually observed during the end of the winter season and before the starting of summer.The  phenomenon has been routinely observed by the annual butterfly survey for the last twelve years. The survey is the only one to be conducted  in any protected areas in India for such a long period to record the changing butterfly diversity and migration patterns.

Butterfly migration in South India: Changing notions

Despite 12 years of documentation, the mystery of butterfly migration in the Kerala part of Western Ghats in general and that to and from Aralam WLS remains an unsolved mystery for many reasons. Though the migratory behavior among butterflies were thoroughly studied in many countries (the monarch migration from US to Canada, for instance), the scholars in the country are yet to crack the nut of complete secrets of these winged travelers.

Butterflies in mud puddling during migration

“In the early years we thought that the migration flocks going through the sanctuary were actually coming from Wayanda and were going to Kodagu in Karnataka through Kottiyoor. However, with the information network getting wider and people from different parts of the state alert us on any sight of butterfly swarms moving in particular direction for prolonged period of time, we now know that the phenomenon is not restricted to a single route or region”, says Dr. Palot. During their later studies, they have found that the phenomenon can be mainly connected with altitude, since the general pattern of Common Albatross migration shows that the flies are moving from high altitude to low altitude and vice versa during specific seasons.

Though the phenomenon is more correctly understood as altitude migration now, many questions are still left unanswered. During surveys in 2008, more than 5000 butterflies were recorded moving down the stream every five minutes, making a rough figure of 4 lakh butterflies during the season. “We don’t know how this much butterflies come up together at a time during the season”, says a researcher.  “Neither do we know where they flies disappear”, adds he.

 “There should be sorts of factory run by nature which produces this much lakhs of butterflies upstream to trigger large scale migrations,” said Dr Palot while interacting with the survey teams. It needs thorough investigations, he said.

Dark Blue Tiger (Tirumala septentrionis) and Crow butterflies
roosting at Aralam WLS

However, researchers got a clue this time, since one survey team spotted female Albatross butterflies laying eggs on a lesser known larval host plants on the migration routes. According to their assumption, the wide presence of the plant could be the factory which produces tens of thousands of Common Albatross butterflies during a migration season.

Pale Four- Line Blue reported from Aralam WLS

According to MNHS sources, the survey has also added a new species to the butterfly diversity of the sanctuary, with one team spotting and photographing ‘Pale Four-Line Blue’ from the sanctuary for the first time in the past 12 years of the survey. With the new report, the sanctuary has 244 different butterfly species, which makes it one among the top protected areas in the country for its butterfly diversity.

The survey has also recorded more than 140 species of butterflies from the sanctuary, with rare sightings like Red Spot Duke, Common Onyx, and the Western Ghats endemic Malabar Tree Nymph. As many as 84 butterfly watchers from Kerala and Karnataka took part in the camp.