Taiwan is home to approximately 400 discovered species of butterflies, of which 180 have been recorded in Yangmingshan National Park. As temperatures rise between May and July each year, nectariferous plants such as the Eupatorium shimadae, the Angelica dahurica var. formosana （Boissieu） Yen, and the Sambucus chinensis Lindl. enter their blooming periods. Many butterflies also undergo metamorphosis at this time of the year, leading to an eruption in the numbers of butterflies and flowers in the park, primarily the milkweed butterfly and the Eupatorium. The butterflies in the Datun Mountains are of the largest scope and are the most easily accessible. They are a spectacular sight. 

The Mt. Datun car lane is an important butterfly-watching route in the park. To preserve plant and animal habitats and offer visitors a safe butterfly-watching experience, all vehicles （including bicycles） except that conducting official park business will be barred from the roads between 8:00 AM and 4:00 PM from 5/31 to 6/22. We ask visitors to comply with these restrictions and we apologize for any inconvenience. 

The Yangmingshan National Park Headquarters would like to call upon butterfly watchers to take public transportation to the park so that they can enjoy the park and the sights at a leisurely pace. Visitors who must drive are advised to park near MRT stations and take the MRT to Jiantan Station, where they may reach the park via the R5 bus. Other transfer opportunities include the 260 and 1717 buses at Taipei Main Station, the 230 and S9 buses at Beitou Station, and the S8 bus at Shipai Station. All of these buses will take visitors to the Yangmingshan bus station or the nearby bus depot, where they may take the 108 bus to Erziping. 

Please be advised that due to the lower temperatures and unpredictable weather in the mountains, visitors should prepare weatherproof gear, warm clothing, and personal pharmaceuticals before setting out. In addition, please do not pick or break plants, disturb butterflies or other animals, or litter. Leave the environment the way you found it!