The ebb and flow of the seasons ranks among the most predictable aspects of the natural world. Astronomers can pin, to the second, each solstice and equinox for decades or centuries into the future. Drawing on a century and a half of scientific data collection, meteorologists can tell you the expected temperature for every day of the year, and forecast divergence from those averages days or even weeks in advance. Alloying existing records with an assessment of the current year, I or any other decent naturalist can go to bed on a particular night confident that the next day will bring the year’s first reports of migrant blackbirds or killdeer.
And yet, every year, spring catches me completely by surprise. I forget how my mind, my spirits, and even my physiology respond to the onset of spring. I forget how comprehensively nature shifts. And above all, I forget how sudden it can be: One moment, it’s dismal late winter, and the next moment, spring has changed from feeble abstraction into certainty.
This year, that moment hit around 11:30 on the morning of March 15. At our house in Oak Bluffs, an erratic overcast of marine stratus abruptly burned off. The sun, reaching the same elevation it does in late September, suddenly impressed me with its determination. Resistance was futile: I brought a porch chair up out of the basement, positioned it in the south-facing angle where the side of our outdoor shower meets the back of our house, and basked like an iguana.
With my mind shut down for all purposes except enjoying the sensation of warmth, it took a few minutes to register; but there was an insect perched near me, on the shingles of the house. Of course I couldn’t resist a closer look, which revealed the pattern of a familiar fly: the wood gnat Sylvicola alternatus. Somewhat reluctant to leave the sunlight even for a moment, I went inside, grabbed my camera, and took some photos.
In my wintertime mindset, one fly would be enough for the day. But warmed by the sun, my brain turned toward abundance and diversity. I surveyed our yard, looking for sites that might offer resources to some kind of insect.
First, the composter. We have a couple of those units with rotating drums that we load with a mix of wood shavings and kitchen scraps. Many flies grow to mature in decomposing organic matter, so I gave the drum currently in use a spin, opened the hatch, and poised the camera to capture whatever I had roused. I only managed photos of one species, some member of the family Phoridae (also called humpbacked or scuttle flies). But two other species also emerged, one a minuscule gnat, the other a small fly likely in the family Scatopsidae (“minute black scavenger flies”).
With the tally at four kinds of flies, I searched for other potential resources. As I pondered, I recognized the distinctive buzz of a honeybee as it flew past my ear. I followed this bee, my first one of the season, as it zeroed in on the remains of a daffodil bouquet. Chucked into the back yard once their time as a centerpiece had ended, the flowers had grown most promisingly slimy. I moved in, camera at the ready, and was rewarded with photos of the bee as it attempted to forage on the spent flowers.
But the bee was not the only customer. An assortment of flies buzzed around the flower rubble, landing periodically to dash around the stems and sponge up the moisture seeping from the decaying blooms. I sat on the ground, straddling the defunct bouquet with my feet, bracing my elbows on my knees to steady the camera, and began watching and photographing: two familiar blow flies, Calliphora vicina and Phormia regina; a cluster fly (genus Pollenia); two other calyptrate flies, one probably in the genus Anthomyiidae, the other a complete puzzle; and, recognizable in part by the array of spines on its legs, a predatory adult fly in the genus Scathophaga. A total of 10 species now!
My next stop was at our three American holly plants. The leaves of this native shrub, popular for some reason as a perch for a wide range of insects, yielded a Syrphid fly and a second fly species that I could get nowhere with. I did, though, manage photos of a colorful leaf hopper, Graphocephala versuta, and the nearly mature nymph of a bug in the genus Lygus, both of which must have overwintered nearby.
And, darn it, I completely forgot to check the crocus blooms in the front yard! I’ve made my first blunder of the year.
Having lived almost all of my 63 years in eastern Massachusetts, I’m not naive about spring in our region, or on the Vineyard in particular. Tomorrow could bring a nasty cold snap, or 18 inches of soggy snow. And it could be mid-June before warm weather truly settles in. But just before midday on March 15, the trajectory of the world changed. At once predictably and astonishingly, nature turned away from frost, and embraced diversity and renewal. Spring!