Taiwan's butterflies have yet to attract the kind of international attention the island's birds now enjoy. But just as birdwatchers come to seek out species seen nowhere else in the world, butterfly enthusiasts who arrive at the right time of year can see a remarkable natural phenomenon: The annual 250km migration of purple crow butterflies (紫斑蝶).
To the untrained eye, Taiwan’s four Purple Crow species are hard to tell apart. Wingspans range from 60mm to 75mm. All four appear dark brown when stationary, but eye-catching patches of blue and purple become visible when they open their wings.
Researchers and volunteers are working hard to better understand the lepidopteran treasures that flutter in Taiwan's fields and forests. Travel in Taiwan recently met up with some of these dedicated individuals for a whistle-stop tour of two purple-crow hot spots – Linnei in Yunlin County (雲林縣林內鄉) and Kaohsiung City's Maolin District (高雄市茂林區).
Approaching Linnei by train, it's the hills inland of the railway line which grab your attention, and we soon learn that topography is one reason why this little township is a bottleneck along the purple crows' migration route. Prevailing winds and the availability of food also influence when and where the butterflies move, but in recent years a stretch of National Freeway No. 3 in Linnei has become famous for the vast number of purple crows (sometimes 500 to 1,000 per minute) who fly over it early each spring. In 2007 - in a move reported by the BBC, National Geographic Channel and other global media - the authorities closed one lane of the freeway and erected 4m-high fencing along one side in an effort to cut the number of butterfly road casualties...
The complete article is in the May/June issue of Travel in Taiwan magazine.