Black Fly Patrol

Beating New England's prodigious spring pests

May 18, 2024

Approaching Eliot Tower on Great Blue Hill

Last weekend, I decided to traverse the Skyline Trail, which visits every summit in the Blue Hills Reservation near Boston. It all started off swimmingly. The rock slabs had already dried off, after a night of rain. My breathing was labored but not terminal, as I hauled ass up the southern slopes of Great Blue Hill (the tallest of the hills.) And I had a hefty can of Italian wedding soup in my backpack, which I was looking forward to savoring on one of the forthcoming hilltops. But as soon as I arrived at Eliot Tower, at the top of Great Blue Hill, a cloud of bedeviling bugs made me realize that this long day hike was about to turn into an ordeal. The insects were dive-bombing toward my facial features, wedging themselves into the crooks behind my ears and the tight crevasses where the edges of my baseball hat met my scalp. Oh no, not again, I thought to myself. Because I have been here before, and I’d imagine you have too.

Black Fly Season has arrived early in several corners of New England this year, thanks in part to the very mild winter we just experienced. It’s one of the most overlooked yet consequential seasonal moments on the New England calendar, and it works like this. Each fall, the female black flies that are still jumping, cooking, and doing their thing deposit eggs in the waterways of New England. And when the waterways freeze, the eggs are transformed into tiny larval time bombs. When the spring begins and those streams, ponds, and bogs thaw, the eggs hatch en masse, condemning any adjacent humans to incessant biting and pestering. Black flies will always be most prodigious and insufferable near water sources but the boom is so significant that they infest the higher parts of New England as well. This is why many of us have at least once found ourselves on the ridge of some illustrious peak like Mount Kearsarge on a beautiful May afternoon, furiously swatting the air as hundreds of the little buggers pursue us.

Generally speaking, peak black fly activity runs from mid-May through late June. But the duration and timing of the agony is location-dependent. Northern New Hampshire and Maine are the ninth circle of the inferno, with their many undeveloped bog lands: a literal wet dream for black flies. In fact, the black flies of the north country are so numerous and prolific that some backcountry counties in Maine experience a second black fly season during the fall, when some of the heartier fly species that plague the Penobscot River welcome a new generation to the fold. This is why pretty much every hardware or general store in northern New England will have an entire shelf full of bug net products. Not just head nets, but netting suits as well. You either suit up or suffer.

Some of you know this, and what follows might strike you as a beginner’s seminar on being outdoors and enjoying it. But black flies and their peak season have a habit of sneaking up on us—even those of us who have experienced the swarming before, and have made a mental note to avoid the winged, eighth-of-an-inch fuckers in the future. And since this newsletter is about the mossier realms of New England, where you’re likely to find black flies over the next 5-6 weeks, it’s time for a lesson in deterrence.

Making it through black fly season without giving up hiking altogether can be broken down into two strategies: avoidance and defense. Just like Clarice Starling, trying to capture Buffalo Bill by profiling an even more notorious serial killer, Hannibal Lecter, we must understand the black fly before we can beat it. And the thing to know about black flies is that they’re creatures of habit. While the exact timing of their birth can be hard to pinpoint, their buzzing grounds and their daily schedules can be predicted and avoided. And this can inform our hiking plans for the next month or so. Hikers in the southwest tend to avoid being outside during midday, as the temperatures soar. New Englanders can take the same self-preservational approach in black fly season.

Oven’s Mouth Preserve in Boothbay, Maine

The easiest avoidance strategy, if you don’t mind temporarily limiting your hiking options, is to steer clear of New England’s interior woods until we hit late June. A coastal hike by the ocean or an urban hike that nixes expansive wetlands will be relatively Black Fly Lite. The other, unrelated perk of prioritizing coastal hikes right now is that you’ll also beat the crowds that descend upon destinations like Acadia and Cape Cod once school lets out for the summer. But if the mountains and lakes are calling you RIGHT NOW and you’re torn between wanting to travel there and not wanting to be covered in welts, here’s another trick that can save your skin and sanity.

According to sources such as the UNH entomology department, the black flies in New England tend to be most active in the morning between 9am to 11am, and in the late afternoon and evening from 4pm to 7pm. This gives you a window of roughly five hours to enjoy backcountry spaces with slightly less black fly activity. The flies won’t be absent, by any means. But from late morning through midafternoon, they should be manageable, unless you’re in the heart of a bog or standing in the mucky shallows of a pond. Five hours is usually more than enough time to enjoy a waterfall or a forest bathing stroll. And if you’re climbing a 4000 footer, making it up and down within the span of the black fly window can raise the stakes of the hike in a perversely fun way. (But don’t rush too hard: black fly bites are preferable to tripping and injuring yourelf.)

Still, avoidance only gets us so far during black fly season and there will be moments when black fly activity defies their territorial and timing habits. And it’s moments like these when it’s time to suck up and suit up. While bug repellent containing ingredients like citronella oil or DEET will have some effect on keeping modest fly populations at bay, these sprays and salves won’t help much in northern territories like the Northeast Kingdom or the Maine Highlands. The flies are going to be on you like sesame seeds on a plump bagel, and clothing is going to be your most reliable line of defense from bites and aggravation. There are a few approaches that you can take here. A head net combined with a long-sleeved shirt and hiking pants can get the job done. But there’s a vulnerability to this approach. The sleeves of your shirt and the ends of your pants can be breached by the flies. And this is why I’ve become an unlikely fan of the bug netting suits mentioned earlier. These suits usually contain elastic to cinch off those areas around your wrists and ankles. Plus, they’re quite billowy, which can be a perk during the hotter and muggier days of black fly season, and a cosplaying experience for those of us who’ve appreciated thick books about wizards and dragons and shit.

There’s a gallows solidarity in New England during winter. You’re out there in the dark, straining as you lift your fiftieth shovelful of snow over your head, and at the end of the road, in the glow of a streetlight, you see another neighbor suffering in a similar war. You trade silent nods, as if to say, we shall overcome. The same words seem to reverberate in the woods of New England during May or June, when I’m out on the trail and I encounter a fellow traveler draped in bug netting. Maybe that traveler will be you.

And here’s the audio episode of this week’s Mind The Moss.

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In outdoor cinema news, I truly don’t know how the revived Planet Of The Apes movies have been allowed to be this thoughtful and thoroughly excellent while exiting in a blockbuster landscape that feels increasingly brainless and pasteurized. I’m thrilled to report that the fourth installment, Kingdom Of The Planet Of The Apes, keeps the party going with a compelling story about how mythology is exploited by those in pursuit of power, with top notch acting and some of the most astounding motion capture VFX I’ve ever seen in a movie. Read the great Alissa Wilkinson’s glowing review for the New York Times if I haven’t convinced you to get into these movies.