Large scale migration of Dark Blue Tiger butterflies has been recorded at the Pachamalai Hills much earlier this year, according to a field-level study.
The study was carried out last month by Q. Ashoka Chakkaravarthy, a wildlife conservationist and Assistant Professor of Environmental Science, St. Joseph’s College, Tiruchi, at Pachamalai, which forms part of the Eastern Ghats. Endowed with valleys, ridges, forest areas and waterfalls, Pachamalai, the only hilly terrain in Tiruchi district, is a home for various species of birds, insects and animals.
Usually the Dark Blue Tiger butterflies migrate from southern parts of the Western Ghats to Pachamalai before monsoon in October or November. However, there has been a large scale migration of these butterflies this time in July itself which is too early. A large population of this species had been recorded from the Pachamalai foothills up to 500 metres elevation.
Dark Blue butterflies are a common species found in the hills of southern India and in the Himalayas up to an altitude of 2,700 metres above sea level. Belonging to the Nymphalidae family, these butterflies have close resemblance to Blue Tiger butterflies.
A large number of this species had been found on the ground in the morning hours and the butterflies start flying higher up in the afternoon. He believes that early migration to Pachamalai could be due to climatic factors in the Western Ghats. Post migration, these butterflies breed on mountains and their offsprings migrate back to the plains between March and May.
“This butterfly migration is one of the most charming natural phenomena in south India”, says Mr. Chakkaravarthy adding that the study was done in the morning hours.
While carrying out the study, he could see many Dark Blue Tiger butterflies having got killed by vehicles on the Pachamalai road more so on the week-ends when tourists’ inflow is considerable. The presence of butterflies whose life span is just two months is an indicator of healthy vegetation. Last year, we had recorded common albatross (Appias albino) in large population, he said.
