A Phenomenon of Mother Nature
In an astounding migratory pilgrimage that takes place every autumn, tens of millions of orange-and-black-winged Monarch butterflies from the eastern United States and Canada brave gales and downpours to make the arduous 2,000-mile trip south to winter in Mexico. High-altitude areas (over 8,000 feet) covered with fir trees northwest of Mexico City, which the Monarchs seem to prefer, have been made into natural reserves. By December, as many as 100 million will gather on these slopes, covering every tree in the vicinity. They are so numerous you can hear their wings beating; the combined weight of their tiny bodies clustered in dense layers on top of one another can actually break limbs from the trees. When they fly, the sky appears completely covered with orange and yellow confetti. Exceptionally cold weather in the winter months of 2002 resulted in the death of an enormous number of these wintering beauties, but local officials were surprised to see how quickly the population repropagated and recouped its losses.