Within the Chinnar Wildlife Sanctuary (CWS) in Idukki district, the canopy is a butterfly kaleidoscope these days at many locations. There are millions of them and they are from the Lepidoptera order of butterflies. For them the CWS is a transit point of their annual migration from the rain shadow forest regions of Tamil Nadu back to the higher elevations of Munnar.
Stalking them are hundreds of insect eating birds too and many butterflies can be seen caught in spider webs. Still millions of them reach the destination for which they are bound for. The migration is not undertaken at one stretch. They leisurely halt to feed and breed because en route the butterflies also lay eggs on the larval host plants appropriate for their caterpillars and there are plenty of such plants in the CWS.
In fact their migration is also with a new generation of butterflies bred during their migratory camp in the rain shadow regions spreading beyond the CWS into Tamil Nadu wilderness. The migration is for avoiding the harsh monsoon rains in the Munnar region. The largely unnoticed activity is now gaining the attraction of nature enthusiasts apart from lepidopterists.
The Assistant Wildlife Warden of the CWS, P.M. Prabhu, said that from the Chinnar area, the migration commenced late last week from largely Kuttar, the confluence point of the Chinnar and Pambar rivers. The migration was largely through a course parallel to the Chinnar River for mud puddling on the river banks for intake of minerals.
The eastward migration from Munnar regions to Chinnar and beyond was a pre south west monsoon activity and the return signals that the south west monsoon was coming to a close, said Mr. Prabhu who had been closely studying the phenomenon for the last couple of years and this year a report on it had been submitted to the State government.
The migration would continue till November as the ones that hatch too would be going to the Munnar areas. Roughly about 46 species were involved in the migration. The activity also helped pollination within the CWS, he said.