For the last few weeks, one of nature’s great migrations has been taking place on the east end of Long Island: clouds of large, gold and black Monarch butterflies heading in a steady pulse west along the coast. They generally keep to the dunes, as is it’s more sheltered, but you also see them right by the ocean. It’s a long, perilous journey. From here they head all the way down the eastern seaboard to a province in Mexico where they gather in vast quantities to hibernate. They travel as much as 3,000 miles and face numerous dangers en route: predators, traffic, lack of suitable food. Every day for the last few weeks we have seen them at the beach: a magical sign that the summer is ending. This YouTube video shows them at the end of their journey in Mexico.