Pheromones, wind currents, topography, and photoperiods are all believed to play roles, but much is still unknown about butterfly routes, including the migration routes of crow butterflies in Taiwan.
至於啟動蝶道的原因，已知的有費洛蒙、氣流、地景、光週期等，但仍有許多未知因素，紫斑蝶的遷移蝶道就是其一。