At the end of fall every year, a staggering number of them--over 100 million--migrate 4000 kilometers from eastern Canada to Mexico, where they overwinter in valleys, creating a world-class scenic wonder with over 10 million butterflies in a single valley.
每年秋末，墨西哥帝王斑蝶會以上億隻的驚人規模，像候鳥般從北美洲（加拿大東岸）飛行 4,000 公里，抵達中美洲墨西哥特定山谷集體越冬，形成一個山谷群聚數量動輒千萬隻的世界級生態景觀。