From Thengumorahada at one end of the Nilgiris bordering Erode to Gudalur on the other end abutting Karnataka an interesting phenomenon has for the past couple of weeks been engaging the attention of observers.
Adverted to as butterfly migration, it is, according to scientists, an annual event which occurs either during the monsoon or just after. However, this year they are finding it intriguing as the number of butterflies seen migrating is unusually high.
Swarms of butterflies can now be seen moving through some parts of the district particular along the eastern half of the upper plateau. Pausing now and then to indulge in mud-puddling, to rest and refresh themselves they present a beautiful sight.
Speaking to The Hindu here on Monday, Conservationist and Wildlife Photographer P.J. Vasanthan said that the migratory movement was observed to start late in the morning, peak at noon and continue till late in the afternoon.
The migrant swarms are mainly made up of two species, commonly known as the Blue Tigers and Common Crows with the former outnumbering the latter. The migration could be seen in the plains of Sirumugai, Moyar Valley and the Nilgiri-Wynad region. Swarms were also seen in places like the Commissioner’s Road here.
Spectacular butterfly migrations associated with the monsoons have been recorded in Peninsular India but have unfortunately not been studied in detail. Lepidopterologist D. Jayabalan of the Department of Zoology and Wildlife Biology, Government Arts College, said that such post-monsoon local migrations are common.
The butterflies move from the areas where they emerge and fly together to areas a few kilometres away in search of plants which host adults.
Pointing out that butterflies belong to the indicator species, he said that the mass movement of the insects can also be taken as a reflection of a healthy monsoon. Such migrations can be seen till the end of October, he said.