Butterfly migration from the Eastern Ghats and plains towards the Western Ghats, an annual phenomenon coinciding with the onset of the Northeast monsoon, was below par this year.
Observers of The Nature and Butterfly Society (TNBS), who have been tracking butterfly migration since 2013, say that they could not see large scale movement of butterflies towards the west till date since September, possibly due to below normal rainfall in west zone districts.
The Eastern Ghats complex comprising the Yercaud hills (Shevaroy hills), Pachamalai, Kolli hills, Kalvarayan hills are the major originating places for the migration in Tamil Nadu. Before the onset of the Northeast monsoon, butterflies from the subfamily Danainae, such as Blue Tiger, Dark Blue Tiger, Double-branded Crow, and Common Crow (commonly known as ‘Tigers and Crows’), leave these hills and fly towards the west. But observers saw only a low scale migration of Tigers and Crows since September this year.
