Acopian BirdSavers on the McCoy’s window—Photo: Kathy McCoy

August 2026 President’s Notes – Adventures in Acopian String Theory

by Matt McCoy

THUNK. That dreaded sound that means another bird has tried to fly through our house. The volume gives us a clue about species and survival probability, and our ears can usually identify which window was involved. Kathy rushes over to assess the victim’s condition. She keeps a crash cart on standby: a cardboard shoebox with a bird‑sized hole in one end and a Ziploc bag of warm water. If the bird isn’t dead, it goes into the box with the heated water to help it recover from the shock of an irresistible force meeting an immovable object.

It’s a less‑than‑satisfactory solution to bird–window collisions, and some collisions are simply unavoidable. Cooper’s Hawks seem particularly adept at using windows to improve their hunting success. Some juveniles—especially Pine Siskins—are notably susceptible to this form of unnatural selection. Varied Thrushes just seem to have bad luck. And while it’s easy to blame the birds, we knew who was responsible. It was time for the McCoys to do their part to reduce collisions.

There are a variety of ways to reduce bird window strikes. Our stickers were ineffective—too few and on the wrong side of the glass (turns out it’s better to read the instructions before application rather than after). Our windows are in good shape, so there was no need to buy new ones with built‑in patterns (they look great at the Nature Center). And being sun worshippers, closing blinds during the day in our climate seemed wrong. Ultimately, we settled on Acopian BirdSavers. Unlike the physics string theory that tries to tie everything together (and makes my brain hurt just thinking about it), Acopian string theory is beautifully simple: a series of strings on the outside of windows, spaced close enough (<4” apart) that birds don’t think they can fly between them.

It seemed like a great DIY project, generally within our skill sets. Kathy knows how to use scissors and fire, and I can still run some power tools (the use of which is an irresistible lure for any male involvement in a project). The first 1,000‑foot roll of paracord mysteriously disappeared in our house. Being world‑class procrastinators, we didn’t jump on it when the second roll arrived. However, we kept a close eye on this roll, fearful lightning would strike twice and we’d become string hoarders. A visit from Katja Bridwell—with an as‑yet‑unearned Certified Wildlife Habitat sign—finally spurred us into action.

Once we got started, Kathy’s sewing acumen made short work of cutting the 70‑plus lengths of string. Melting the ends was a little tricky (this is best done outdoors), but once she figured out how to slide the exterior mesh to the end of each piece, clean, tight melted ends were assured. There are many ways to attach the strings above the windows. For aesthetic reasons, Kathy vetoed both the horizontal string with knots at 4‑inch intervals and the plastic J‑channel methods. Being a woodworker, cedar trim seemed the obvious solution—easy to work with and can be painted so it blends in.

A 12‑foot‑long 1x4 board, ripped in half lengthwise, provided enough material for six windows and a slider. Woodworkers, please note: in this case the “1” is the actual finished thickness, but the “4” is really a 3.5‑inch width—mostly, I suspect, because trim folks want to distinguish themselves from framers. Normally I obsess over 1/32 of an inch when woodworking, but birds couldn’t care less, so “pretty darn close” was just fine for this project. My parents got a Shopsmith Mark V in the early ’60s to build a 27‑foot camper that brought us countless happy memories (how they kept all their fingers intact while running sheets of plywood through it is a mystery to me). Its drill‑press function would have been a great option for this project, allowing accuracy, speed, and repeatability. Sadly, the Shopsmith isn’t very accessible, so the artistic whimsy—drunken woodworker style—of handheld drills was employed.

With over 70 holes to drill, I had plenty of time to ponder the meaning of life (the merits of English vs. metric measuring systems; whether the Shopsmith was really that inaccessible; how long a piece of string actually is). The holes needed to be large enough to accommodate the melted paracord ends—a 1/4‑inch bit worked fine—and countersinking ensured that the top knots would disappear. Drilling holes after painting would have cut the drill work in half, as paint drips negated those finely tuned hole sizes.

“Measure twice, cut once” is a sacrosanct woodworking rule I have yet to master, and this project was no different. Instead, a measure‑once‑from‑inside‑the‑house, cut‑70‑plus‑times methodology produced predictable results. That technique didn’t consider where the strings would be mounted above each window, the mounting method, the knots, or potential shrinkage (something I read about only after completing the project—because what self‑respecting guy reads all the instructions before starting?). Consequently, we have a capri‑style rendering, ready for high water.

Typically, when a guy embarks on a new project, the most important consideration is “what new tool will I need to buy to complete it?” By that measure, this project failed miserably—we had all the necessary tools. However, from a bird perspective (which it could be argued is why we did this), it appears to be a resounding success. Just one gentle thunk and no mortalities so far. If birds find your windows irresistible, I’d encourage you to try something else. A few strings can make a world of difference to those doing the flying.