Avantgardens. Monarch Butterfly amazing migration - BBC Life Native to the West and Midwest of the Americas, monarchs travel on an annual migration through Canada, California and Mexico, pausing along the way to gather in enormous flocks of tens of thousands of butterflies. They gather in such incredible numbers that trees appear to be draped in orange-and-black leaves, which upon closer examination resolve themselves into fluttering wings. It was only in the 1970s when Canadian entomologists Fr