Taiwan’s four crow butterfly species – the blue-banded king crow (Euploea eunice hobsoni), the double-branded crow (Euploea sylvester swinhoei), the striped blue crow (Euploea mulciber barsine), and the dwarf crow (Euploea tulliolus koxinga) – are distinguished by their white markings; A popular Chinese mantra is often used to differentiate between them: “The dwarf has one spot; the blue-banded king, two; the double-branded, three; the striped blue, scattered ones.”
Visiting Maolin National Park’s Purple Butterfly Valley this past December, my friends and I were able to catch a glimpse of the Crow butterflies ourselves. Seeing them for the first time, and thousands of them all in one place, we were in awe. Never had we seen butterflies as colorful and majestic as these. Their deep black, blue, and purple coloration set them apart from the ones we were used to seeing in the U.S. I can see why so many people travel from Kaohsiung City and around Taiwan to see these magnificent butterflies for themselves!
Each winter, it is estimated that 100,000 to 200,000 Purple Crow butterflies migrate south through Maolin, seeking shelter in the warmer climate of the valleys found at the base of the Dawu mountains. This migratory pattern is what creates Maolin’s iconic Purple Butterfly Valley, almost as famous as America’s “Monarch Butterfly Valley”. While the butterflies spend Taiwan’s winter – November through March – in the island’s warmer southern valleys, you can find the Purple Crow Butterfly migrating back North, come Spring.
