The big migration many travellers want to witness is the annual movement of wildebeest 3,000km miles across the Serengeti. With good reason; the animals’ crossing of the African plain is often considered one of the wonders of the natural world. Compared with butterflies, though, wildebeest are wimps.
Every year, despite weighing no more than a postage stamp, the mighty monarch butterfly makes an epic journey to central Mexico from as far away as eastern Canada, a distance of some 4,500km. What makes this achievement even more amazing is that only one generation in four will undertake it. This is because monarchs normally live for a month or so. Once a year a “Methuselah generation” is born, and it is this generation, which will live up to eight months, that undertakes the perilous task of bringing an entire species back to its overwintering colonies.
In human terms, this geriatric generation of butterflies would reach the age of 525. Despite their advanced years they flutter furiously for up to 130km a day, with a billion of them eventually making it to a forested region 100km north of Mexico City, where they settle down to hibernate. Such is their collective weight that the mighty fir trees there sag under them.
Come February, when the sun warms up, they awaken (left) to create an unparalleled spectacle – so many that you can hear their wings beating. A quick stretch and off they go again, in generational relays, back up north. It’s a once-in-a-lifetime experience, for you as well as them, best witnessed at Monarch Butterfly Biosphere Reserve, a Unesco World Heritage site.
whc.unesco.org/en/list/1290