❖ Tamil Nadu has witnessed large-scale migration of butterflies belonging to the Danainae sub-family from the Eastern Ghats and plains towards the Western Ghats during September.

❖ They migrate from the Eastern Ghats and plains towards various nearest hill ranges of the Western Ghats before the start of northeast monsoon.

❖ During April and May, these butterflies, generally called ‘tigers and crows’ migrate from the Western Ghat hill ranges towards the Eastern Ghats and plains of Tamil Nadu.

❖ This is happened before the onset of the southwest monsoon.