Of all the sky’s astonishments, few can match the monarch butterfly for dainty durability even beyond the scope of a single lifetime. We’ve all heard of their seasonal migrations extending between central Mexico and eastern Canada, thousands of miles further than one butterfly could ever go. So, two generations each way to complete the loop? A brief googling exposes this as only vaguely factual. The more I read the less certainty there is of anything – always a sign that the trail will be a long one.
So far the biggest surprise is the idea of five generations to complete one migration cycle. How’s that work? And over how many years? Assuming a fresh departure from Mexico every spring, do different generations pass each other heading opposite directions? And how do they do it?
Nobody knows. Presently, theories outnumber explanations, with little agreement except that other migration behaviors also exist, including some monarchs who don’t migrate at all. There’s evidence for and against some mix of genetic memory and/or an internal brain map preprogrammed to recognize certain geographic features. You can bet there’s more to it than that.
Birds have been proven to use a whole suite of nav systems, including celestial and magnetic, so why not butterflies? There are diatoms (single-celled algae) living deep in beach sand who rise to the surface only for full moons… Gotta wonder.
Here’s where I pitch my typically non-scientific observation, answering no questions but raising more. Of the sixteen seasons I soared in Vermont, only one was sanctified by an intensive visitation of monarchs. For weeks that summer you couldn’t fly midday without your leading edges turning an icky shade of orange. Canopies too of course. Awfully sad at first, but you had to get used it. I remember cheating on minimums – shhh – and watching clusters of monarchs loft into cloud base like thousands of tiny Lord Jesuses ascending en masse to Glory.
(Entirely unrelated but exactly the same, you haven’t really experienced autumn in New England until you’ve risen with it in florescent tutti-fruiti swirls of ‘fallen’ leaves twirling high into the sky, and yes, the clouds as well. Sorry, off topic but I couldn’t resist.)
Back to the inexplicable peregrinations of monarch butterflies, my main question is why we got to enjoy them only one year out of sixteen, and where they went during those other fifteen cycles. I ask that every time I see one, but they never want to tell.