Almost all Monarch butterflies in North America spend the winter hibernating in pine forests on a mountain range in Mexico, except for a small contingent that steals away to winter in southern California. In the spring, they flutter down the mountain, and head north into the southern U.S. They lay their eggs after a few weeks, and then they die. The butterflies that hatch from that first generation will never, ever, ever see the mountain forests their parents sojourned in. Neither will their children.
Once, biologists believed that Monarchs completed the annual cycle in two generations: parents overwintered, migrated north, reproduced, died; that summer’s young ate, grew, pupated, metamorphosed, migrated south, hibernated, and started the cycle again. Then, someone asked the (possibly stupid) question: Are we sure about that? And they realized they weren’t sure. So someone gave someone else money to glue teeny tiny tracking devices to unreliable butterflies for possibly no very good reason at all, except to satisfy a silly sort of wager. Science is awesome. It revealed a miracle.
Each year, Monarch butterflies push north in three waves, each generation migrating, reproducing, and dying, until their decendants are spread throughout North America. Then, starting in late August, the great grandbabies of the overwintered butterflies turn around, and begin relentlessly pressing south, aiming for mountains they’ve never seen. Their great grandparents are long gone. No one tells them where to go, or shows them how to get there. Some mysterious, miraculous biological switch flips only in that fourth generation, and millions of butterflies from the four corners of the continent navigate past cities, mountains, and enormous lakes they can’t possibly use as landmarks to end up in the same sheltered area in the Mexican mountains to sleep for a few months.
Genetic GPS. It’s the next big thing. And a big, old thing.
In the past few weeks, I’ve seen more Monarch butterflies than I could have counted all summer. They flutter singly across parking lots. They doggedly beat their way west down the highway, slipstreaming over my hood and up my windshield (fortunately evading the grill of my car). And they blow onto the beach from open water in long skeins, presumably after realizing there’s no land south of Long island until Antarctica. So many butterflies, I’d almost stopped noticing them.
The other evening, I drove down to the bayside marsh to feel the sunset on my eyelids. Butterflies bobbed overhead, dozens at a time, all headed west. As the sun sank lower, they started lighting on trees and shrubs, letting me sneak closer peeks. They’d startle and re-settle, a handful here and there.
The sun dipped lower, and I headed back to my car. As I buckled my seat belt, a woman drove up next to me, rolling down her window. “I saw you were taking pictures. I thought you’d like to know, there’s something amazing happening in a tree up the road.”
Note to self: people tell you about wonderful things when you carry a camera. Self, carry a camera all the time.
The light was fading behind me as I pulled off onto the gravel in front of a now-quiet nightclub. “So Long, Summer 2012!” the sign read. Suckers, I thought. They don’t know what they’re missing. I crossed the empty road to a stubby line of pine trees, and shoved through the branches into a small clearing. As soon as I stepped out, the trees erupted into orange wings. Butterflies by the thousands tiled the branches of the pines, hanging like umber flags among the pinecones and needles. So many, their wing beats drummed the air like a muffled bass, while the dusty, singed scent of their accumulated furry bodies tingled in my nose.
I really can’t disguise how awesome I thought this was, this phenomenon in my backyard, this (random? annual?) event that connects my place with another, entirely different place. Just as they would thousands of miles and several weeks from now, they had gathered by the horde, perched safely out of reach of cherry-picking predators, to be warmed overnight by the concentration of their collective metabolism. They’d been funneled here by a coincidence of geology and polar magnetism, the stretched arm of Long Island reaching northeast out into the Atlantic to catch them before the open ocean, to safely guide them westward to the mainland, and on southward to Mexico.
Next September, I’ll head down to the bay with some year-old questions of my own to answer. When I go back, will their great-grandbutterflies be there too, in the same trees, in the same numbers? Or will I eventually seek them out in their mountain refuge, with the scent-memory of their accumulation tugging me south at last?