Naturally: Buckeye butterfly migration passes through San Benito County

Clouds of the creatures have blown through the region

I don’t know if you’ve noticed, but there’s something wafting in the air in San Benito County. Actually, a few million somethings are floating through, mostly bound from south to north.

I’m talking about a modest little butterfly, clad mostly in brown, but with two prominent spots on each pair of wings that resemble an owl’s eyes. The buckeye – Junonia coenia – has appeared in staggering numbers this year. Never particularly rare, the butterfly is found across most of the country. 

Its caterpillars feed on plants that are commonly regarded as weeds, plantago and toadflax, along with the not-so-weedy snapdragon.  After an errand downtown and back on a bicycle last week, I encountered these butterflies every few feet. Corpses littered Hillcrest Road.  Looking around, there were clouds of them blowing through.

Of course, I began talking about the phenomenon to anyone who would suffer to listen. But to a person, nobody else admitted to having noticed. That’s not unusual. I seem to pay more attention to the wild things around us than most people. It’s a combination of having the inclination and making the time to stare at bugs, birds and everything else that shares space with us.

So naturally, I turned to The Greatest Library in the World, AKA the Internet. Of course, learned scientists must be discussing this phenomenon. And I found … nothing.

Some years ago, another common butterfly, the painted lady, exhibited the same kind of population explosion. It was news in papers and evening news broadcasts across California and beyond. So why didn’t I find any mention this time?

I suspect the reason may be due to the bipolar personality of our weather this winter. A wet December, and a dry everything else has produced a compressed wildflower bloom, with everything going off at once.  But without an authoritative opinion from someone whose life is devoted to butterflies, I’m left to guess and wonder.

The movement of buckeyes seems already to be waning. Each year, the butterflies disperse northward from the West Coast and the Southern Tier of states, but never in numbers like this that I’ve noticed.

Buckeyes like open country with low vegetation and some unvegetated spots. Kind of sounds familiar, doesn’t it?

Butterflies exhibit two behaviors when seeking a mate. Many years ago, our two daughters noticed that British nature documentaries in particular, seemed to turn inevitably to the subject of sex. And who am I to depart from the norm?

Butterflies, with brains that could nestle comfortably on  the head of a pin, employ two “dating” strategies. There are perchers and patrollers. Patrollers fly around, seemingly aimlessly, looking for love. They have an instinctive urge that increases their odds of getting lucky. They fly uphill, a behavior known, creatively enough, as “hilltopping.”

Some friends climbed Mt. Lassen a few years ago, and found its snowy summit littered with cold-blooded butterflies who had hilltopped themselves into a place where they would almost certainly perish.

Buckeyes employ a less labor-intensive approach to getting a little action. Perchers rest on the ground, and when something likely flits by, they take wing to check things out.

Thus, it’s common to see buckeyes resting on trails or other bare patches of land.

They also frequently gather around the edges of puddles to sip water or glean minerals.

These humble butterflies are a reminder that there are many lifetimes worth of things to wonder at surrounding us every day.  I love the sight of a child who drops into a sudden squat to peer at a line of ants or a caterpillar on a garden path.  That sense of wonder is a gift that we all deserve to cultivate long after we’ve left childhood behind.

Mark Paxton

I've been at this most of my life, and it still fascinates and challenges me. San Benito County can be a cruel mistress at times, but we can share in our love for her, even with all her quirks.