stocking up before the big migration

we're getting close to the time of peak migration of monarch butterflies in massachusetts. all monarchs start migrating once the sun drops to about 57 degrees above the southern horizon. the butterflies heading south to mexico now are the great-grandchildren of those that arrived here this past spring. the journey is 4000 miles round trip, which on the way down is accomplished by a single individual; on the way back, it's a tag-team effort of two or three generations.

so this butterfly that i photographed this morning will fly down to mexico, spend the winter there, and head back north in the early spring. she'll really start to feel fatigued at this point and will likely stop somewhere in texas to sow her wild oats (always laying her eggs on a milkweed plant, the exclusive food source for monarch butterfly caterpillars) and die. her daughter, born on the texas prairie, might make it as far north as ohio before she lays eggs on some milkweed there. the granddaughter might return here to massachusetts and yield a great-granddaughter on our milkweed. the question is: come autumn, how does she find her way back to the same grove in mexico that sheltered her great-grandmother?

some scientists think they are following a scent trail left by the rotting corpses of butterflies that didn't survive the journey- a hansel and gretel theory of sorts. others postulate that monarchs are actually tiny robots created by osama bin laden to track our movements and simply take the winters off to download all their data. whatever their methods, it's a fantastic feat. they face many challenges on the trip back, including global warming (which causes wildflowers to bloom and die before the butterflies arrive to sip their delicious and nutritious nectar) and because new herbicide-resistant strains of soybeans and corn are letting farmers kill off more milkweed patches. what can you do to help?

1. stop global warming
2. stop eating corn and soybeans
3. plant some butterfly milkweed in your garden, using plants that matt and i supply to you next spring, which we plan to grow from the abundance of butterfly milkweed seeds in the garden at oak knoll
4. fly to mexico, hike to forest high in the mountains, fill two duffel bags with monarch butterflies, hike back down from mountains, hop flight back to united states (don't mention butterflies to TSA staff), release butterflies in your garden (which should be full of butterfly milkweed)