I have a soft spot in my heart for monarch butterflies. As I described in The Path: A One-Mile Walk Through the Universe, I once had the opportunity to visit the forests in central Mexico where the monarchs of eastern North America retire for the winter, after flying thousands of miles from, say, my neighborhood here in New England to a particular patch of fir trees they have never visited before.
Reaching the butterflies' winter refuge required a harrowing bus ride from Mexico City over narrow mountain roads, then a hike along trails billowing with fine volcanic dust. At last we stood in silent awe among trees festooned with millions of monarchs, butterflies as dense as leaves. When the sun broke through the clouds, the monarchs took to the air, filling the sky with their glorious wings.
The visit to the Mexican monarch refuge was one of the two most thrilling natural adventures of my life, along with a total solar eclipse seen from the middle of the Black Sea.
The monarchs that fly from New England to Mexico are at least two generations removed from any butterflies that have previously made the journey. How do they do it? How do they find that patch of trees? Those fragile slips of chitin with pin-point brains? The clock, the map, the navigational skills must be genetically embedded in the monarch's DNA, that twisty helix of "four-letter" code.
Now the monarch's genome has been sequenced by neurobiologists at the University of Massachusetts Medical School. Two-hundred-seventy-three million base pairs. Nearly 17,000 protein-coding genes, including many that are likely to be instrumental in the seasonal migration. But identifying genes and proteins is still a long way from knowing how the insects perform their awesome feat of navigation, particularly as they start their journey from places hundreds of miles apart, and end up, so to speak, on a dime.
This is one of those things -- like consciousness -- that becomes more apparently miraculous the more we illuminate the essence of the miracle. The supernatural pales in comparison to the natural. Who needs the paranormal when the normal is so astonishing?
We have a tiny patch of milkweed -- the monarch's sole food plant -- near the compost bin in the backyard. I've never seen a monarch there, but I preserve the milkweed as a kind of shrine to the mundane. The mundane is shot through with wonder.