Where have all the butterflies gone?
I had planned to write this week about how often it is that a
person comments that they wonder where I get the time to do all the
nature watching I seem to do.
Where have all the butterflies gone?
I had planned to write this week about how often it is that a person comments that they wonder where I get the time to do all the nature watching I seem to do.
The truth is, I have neither the time nor the budget to spend weeks traveling to far-off places. But it’s easy to find fascinating interactions with wild things close at hand with just a small expenditure of time.
There’s much to learn even in common places. Or not.
Which is what caused me to re-think this essay.
What gave me pause was a note this week from a reader who failed to identify himself or herself. The letter gives a few things away, that the person has been in the area since the 1950s, and knows a few things about butterflies.
“What happened to the common butterflies I saw in the 1950s?” the writer asked, going on to name monarchs, buckeyes, California sister, skippers, blues, hairstreaks, sulphur dog face, mourning cloak and a host of others with names at least as entertaining as those already listed.
“Is it the air, water, MTBE, pesticides, no wildflowers?” the writer asked.
The writer went on to say that he lives on the east side of Hollister, surrounded by flowers, and recently has tallied only a single monarch and a handful of cabbages. “Have we already passed through Rachel Carson’s ‘Silent Spring?'”
His last question refers to the seminal book that many credit with launching the environmental movement more than a generation ago.
His poignant questions prompted me to return to the database built by an obsessed researcher. Arthur Shapiro, a member of the faculty at UC Davis, has spent more than 34 years amassing a database of California’s butterflies. During that time, he has logged nearly 6,000 site visits, counted 83,000 individual butterflies and collected 159 species.
And without producing any single definitive answer for why butterflies might be declining, Shapiro’s census data shows what my correspondent noticed – that numbers of many species do appear to be declining.
Part of the reason may be climate change, according to Shapiro’s research. Some 70 percent of the butterflies being tracked were hatching earlier, on average.
But the important bit of information to be gleaned is that Shapiro, often described as one of the world’s leading experts on butterflies, himself has not pointed out what may be the cause.
Part of the reason, certainly, is that populations are very dynamic. Lemming numbers peak and crash famously. Some people said they observed larger numbers of crickets than usual in Hollister. From the plagues of locusts in the Old Testament to the black plague in Europe, if there’s anything we know it is that populations are influenced by a host of factors and that teasing out the “aha!” answer why is nearly impossible.
Just a few years ago, there was such an explosion of painted lady butterflies that I stopped alongside Shore Road for a few minutes, just to watch clouds of them fluttering north. Trips through alfalfa fields in the Central Valley are guaranteed to paint windshields and grills with sulphurs.
Let’s hope our apparent dearth of butterflies this season is just another part of the population pendulum swing.
