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The Subtle Butterfly Migrations of Taiwan

Every year in the winter and again in the early spring a few million butterflies migrate from northern and central Taiwan to the south.

Every year in the winter and again in the early spring a few million butterflies migrate from northern and central Taiwan to the south. In some areas the butterflies are so prolific that nets have been installed over certain freeways to encourage the butterflies to fly higher to avoid colliding with vehicles.

The migration of Taiwan’s purple crow butterflies is one of the two largest butterfly migrations in the world – the monarch butterflies of Mexico being the largest.

ABOVE: Large purple butterfly (Sasakia charonda) in Taiwan.

They travel nearly 400 kilometres, assisted by strong winds from Mongolia and China to settle in the valleys in the Dawu Mountain Range by November. The mountain range has between 12 and 15 sheltered, warm valleys where the butterflies can spend the winter.

The Maolin National Scenic Area, also known as the Purple Butterfly Valley, located less than an hour from Kaohsiung. Travelers aren’t likely to see hundreds of butterflies in the sky, but anywhere long the Purple Butterfly Valley travelers will surely see a few of these little critters in one of the planet’s only mass butterfly migrations.

A member of the Butterfly Conservation Society of Taiwan, Chan Chia-lung, has been working with the Council of Agriculture to implement conservation and education program in the area. They mark and track the butterflies in an attempt to map more exact migration patterns. Local residents assist through offering tours, patrolling the valleys, and growing plants to feed the butterflies. In 2002 the Purple Butterfly Valley Conservation Society in Maolin was established. Through the conservation efforts local people are able to generate income from tourism instead of catching butterflies for commercial purposes.

ABOVE: Dwarf crow butterfly.

Chia-lung has also collaborated with the Taiwan Area National Freeway Bureau to erect the world’s first ‘Butterfly Safe-Corridor Initiative’. The ‘Butterfly Safe-Corridor’ consists of tall nets set up around certain freeways that the butterflies cross during their migration, and when the number of butterflies crossing a freeway exceeds more than 500 per minute, some lanes of these freeways might even be closed to allow them to cross safely.

Maolin Ecological Park offers free guided tours through their visitor center. The guides accompany visitors to the best spots to see large amounts of these blue-purple butterflies on a trek that lasts between 45 minutes to an hour. Although Taiwan has around 400 species of butterfly, Dwarf Crows, Double-branded Black Crows, Striped Blue Cows and Blue-banded King Cows make up the majority of the population in the Purple Butterfly Valley. This population can consist of nearly 1 million individual butterflies. It is estimated that between 10 and 15 million butterflies settle in the larger Dawu Mountain Range for the winter.

ABOVE: Purple crow butterfly in flight.

At first the butterflies might seem dark blue or even black, until the sunlight catches their wings just right. When this happens visitors could themselves surrounded by swarms of deep purple, nearly luminous, butterflies.

In March these butterflies (many of the same individuals who travelled south a few months before) migrate back up north, this time being pushed by winds from the Philippines.

The route that the butterflies follow each year, going north, starts in Maolin, travels through Moon World and Tanayiku Valley to Chiayi, Hupen Village. They then move on to Linnei Township, Yunlin, Pakua Mountain, Changhua, Tatu Mountain, Taichung, and then to Huoyen Mountain. The last stop along the way is Miaoli before they carry on to Chunan, Hsinchu.

Some of the best places to see the spring migration, moving from south to north, are Linnei, Dawu in Taitung Country, Pingtung Country Rd 199, Taichung’s Metropolitan Park, Baguashan and the coastal areas of Jhunan in Miaoli County. For some reason large numbers of these butterflies get blown back southward toward the Tatajia mountain pass in May and June.

Other areas to see butterflies in Taiwan include Yangmingshan National Park’s Datunshan, Fuyuan Forest Recreational Area, and the Yellow Butterfly Valley outside Meinong.

Taiwan is known as the ‘Butterfly Kingdom’ and there are many places to see these creatures in their natural setting. Few of these spaces are as impressive as seeing vast amounts of bright purple butterflies fluttering through the vegetation in the Purple Butterfly Valley. This spectacular natural phenomenon is so impressive that it does, in fact, stop traffic.