Continuing this week’s theme of amazing animal migrations, today it is the turn of those winged wonders that cover some incredible distances year in, year out. Migration is often associated with flight, and it is no surprise when you consider that birds hold some of the most incredible records when it comes to annual voyages around the world.
Arctic Tern – Between Greenland and Antarctica
Currently the record holder of the longest migration of any creature on the planet, this tiny bird has been found to travel distances up to 44,000 miles ever year in its journey between Greenland and Antarctica. Previously too small to be recorded accurately, this illustrious title was thought to belong to the Sooty Shearwater, which is not far behind with a recorded migration of about 40,000 miles. The Arctic Tern can live for up to 30 years, meaning that over its lifetime an individual probably travels a total of about 1.5 million miles, equivalent to three trips to the moon and back. A truly out of this world, head-terning traveller.
Monarch Butterfly – Between Canada/USA to Central Mexico
Not all migrations by air are those of birds: the journey of the Monarch butterfly is one of the most amazing and interesting occurrences in the natural world. A normal Monarch butterfly only lives for between 4-5 weeks. However, once a year, a special Methuselah generation of individuals is born. This individual is remarkably able to live for up to eight months, the equivalent of a human living to the age of 525. The reason for this unbelievable phenomenon is the need to migrate. This special generation must fly between 1,200-2,800 miles south from their breeding grounds in Canada and the USA, to Central Mexico, to avoid the harsh winter. Guided by the sun’s orbit, the butterflies have been known to cover distances of up to 80 miles per day, an amazing feat for such a small creature.
The arrival of the butterflies in the forests between the states of Mexico and Michoacan is a true natural wonder. Here they hibernate from mid-November to mid-February, when they begin the journey back. However, the Methuselah generation cannot make the return journey on its own, eventually dying on the way. In another incredible twist to the journey, a succession of normal generations take over the flight, gradually making their way north. The individuals that return to the original breeding grounds have never been there themselves, with a sense of orientation thought to be passed on genetically from the great, great grandparents that first set out on the migratory trip. Wow.
By Alex Prior