When summer rolls around, this decreasingly young man’s fancy inevitably turns to bugs. This mainly means butterflies here in mid-July, followed by the many ticks crawling up my legs after a day in the field looking at butterflies. But never mind that part, I’m here to hook you on bug watching, not send you screaming to the exits.
Mid-July is when my two, all-day butterfly counts happen, scheduled to coincide with peak of the summer flight period. These counts were started in 1993 by the North American Butterfly Association – is your membership current? These so-called “4th of July Butterfly Counts” are patterned after the longer-running Christmas Bird Counts, in that teams of observers tally every butterfly they can in some subset of a 15-mile circle on one day. We don’t attract the same volume of personnel that the bird counts do, so we make up for the more modest coverage with consistency – we thoroughly check the same locations within the circle each year.
This past Sunday was the Truro count, which covers from Highland Light in Truro to Hatches Harbor in P’town. We start the day working the ragged edges of the golf course by Highland Light, a gorgeous, rustic course that blends into the surrounding National Seashore, with milkweed and other nectar sources between the fairways. The morning was slow and cloudy, with low numbers, but we managed ten species there, including one paltry Monarch.
We spend a lot of time staring at nectar sources that might concentrate otherwise peripatetic butterflies, right now it’s mainly invasives like wild old privet shrubs and spotted knapweed, but also both common and butterfly milkweeds, and even abundant white clover on someone’s lawn held two little Gray Hairstreaks. In Provincetown we discovered a few years ago a little swamp just off a main road where handsome and normally scarce Striped Hairstreaks gather to drink nectar. They drink from the tiny flowers on an obscure wetland shrub called Maleberry, which often grows with highbush blueberry, one of this species’ preferred caterpillar hosts. I saw at least 14 there on Sunday, elsewhere we saw none.
We put on rubber boots to scour a wet wild cranberry bog just off rt 6 in P’town, overgrown with red maple, willow, and various tussock grasses and sedges. If not for the overturned bleachers, you’d never suspect this was an old athletic field built by the Navy in 1905 to keep the fleet, sometimes totaling 4000 sailors at once, occupied with sports during shore leave so they didn’t pursue less savory activities. It’s still called Evans Field, named after Rear Admiral “Fighting Bob” Evans whose officers built it. Now it’s where we look for the only population in the count area of a butterfly called the Appalachian Brown, as well as the Bog Copper, a mothy little butterfly no one would likely notice, even if they were willing to wade into their mosquito-laden lairs as we have, and whose caterpillars feed on wild cranberry.
All told we saw 23 species of butterfly on Sunday, well shy of our all-time high of 39. Numbers and diversity seem to be trending down in recent years, and a national study just published in the journal Science, using data from these 4th of July counts, showed a 22% decline in butterfly abundance since the year 2000, with 13 times as many species declining as increasing, including here in the northeast. You can help by eliminating pesticides, especially mosquito spraying, and planting native plants in your yard. But you should also join us on one of these counts to meet these species for yourself. So come on out! It’s a really wholesome activity, one that “Fighting Bob” Evans himself would surely approve of for his sailors on shore leave.
