Purple crow butterfly : Migration

In a recent (2001-2005) study, researchers recorded the full-year migratory pattern of the purple milkweed, including the startling sight of this butterfly passing by in numbers of more than 10,000 per minute. Generally speaking, the purple milkweed makes at least three large-scale migrations annually. The first is the northern return migration in March and April. The second occurs between May and early June just after eclosion of the new generation of purple milkweeds. And the third migration is the southern winter journey around mid-October.

 

Confirmed sites on the migratory routes of the purple milkweed are listed below:
 

1. Northbound spring migration: Dawu and Jhihben in Taitung County; Laiyi and Eluanbi in Pingtung County; Maolin, Baolai, and Jhongliaoshan in Kaohsiung County; Zengwen Reservoir and Siangong Temple in Tainan County; Danayigu in Chiayi County; Linnei and Huben in Yunlin County; Baguashan in Changhua County; and Dadushan in Taichung County.

2. Second migration: Guanwu in Hsinchu County; Jhuolan, Sanyi, Jhunan, Tongsiao, and Tongluo in Miaoli County; Shihgang, forest trails on Dasyuehshan, Dongmaoshan, and Tatajiaanbu (Yushan National Park) in Taichung; Yitun, Eluanbi and Fengchueisha in Pingtung County.

3. Southbound migration in winter: Tatajiaanbu in Yushan National Park.