Making way for the butterflies
Chan got together with Cheng Juey-fu and Lin Tie-shyong (associate professors in the Department of Civil and Ecological Engineering at I-Shou University) and contacted the National Freeway Bureau to suggest that protective netting be put up along selected stretches of freeway to help the butterflies get safely over the hurdles. Their suggestion was accepted.
During the northward migration (early March through Tomb Sweeping Day on April 5), the highway authorities work together with environmental groups to put up protective netting, when the butterfly traffic merits it, along National Freeway No. 3 at the 252 kilometer marker, and when the butterflies are especially numerous they further close a 500-meter stretch of the outside lane to make sure the butterflies get across.
Taiwan’s efforts to protect the crow butterflies have attracted international attention, and even featured in programs on National Geographic Channel and Discovery Channel. Every time Chan has gone overseas in recent years to take part in environmental activities, foreigners never fail to tell him of their high regard for what Taiwan has been doing for ecological preservation.
Inspired by Chan, a group of indigenous residents in Maolin formed the Kaohsiung City Maolin District Crow Butterfly Preservation Association.
In addition to habitat destruction, another thing the association is especially worried about is climate extremes, which have become much worse in the past year or two.
Tang Xiongjin, of the preservation association, explains that Taiwan’s climate has become quite hot, causing some plants to flower at odd times, sometimes leaving butterflies, which depend on nectar as their main food source, without their normal fare available. In addition, water sources have dried up considerably this year. Butterflies don’t usually go foraging for water until January, but they’ve recently been appearing at the mouth of the Zhuokou River on precisely that errand. The association is monitoring the situation closely to see whether it will cause a big drop in butterfly populations.
To preserve crow butterfly populations, reports Tang, the association last year leased a mountain valley from the forest authorities and built a footpath and ecopark for visitors interested in butterfly watching. The idea is to get more people interested in and committed to the protection of butterflies. In addition to the leased valley, Maolin District has seven or eight other mountain valleys where authorities carefully limit the number of vehicles allowed to enter.
The two biggest killers of crow butterfly are climate change and habitat destruction. Shown below is a blue-banded king crow. (courtesy of Kaohsiung City Maolin District Crow Butterfly Preservation Association)