MOTH TRAPPING IN THE ARCTIC AIR:WINTER NIGHTS IN CAITHNESS

Working up in Caithness for the next few weeks, I’ve been putting out the moth trap whenever the weather looks even vaguely cooperative. That hasn’t been often.

The recent run of poor weather here, particularly over the first few weeks, has been driven by a stubbornly “stuck” winter pattern. Deep depressions over Scandinavia combined with high pressure near Greenland have created a relentless northerly airflow, dragging freezing Arctic air straight down over northern Scotland. And by god, when you’re not used to an Arctic air stream, it’s cold.

This persistent, direct flow from the North Pole has brought repeated snow showers to the far north, with temperatures low enough to generate windchill values of minus 6°C to minus 7°C. Put it this way: working in ecology up here at this time of year is challenging—and absolutely bloody freezing.

Despite that, I’ve managed to get the moth trap out on two occasions this week. Both nights followed a slight lull in the wind, with temperatures hovering around 3°C. Hardly ideal conditions, but sometimes you take what you’re given.

To my surprise, those brief windows of calm paid off. I recorded five Pale Brindled Beauty moths and a single Chestnut moth. The Pale Brindled Beauties were observed coming to the light initially, but were later found settled on nearby trees rather than in the trap itself. This was a new species for me—one I’d never trapped before—so it was a genuinely exciting find, especially given the conditions.

The Pale Brindled Beauty is a particularly interesting species. The females are completely wingless—apterous—a trait often seen in moths that emerge in the winter months. Unlike the males, females are not attracted to light at all. Instead, they climb tree trunks and wait, making them elusive and rarely encountered despite the species itself being fairly common. Males fly from January through to March, searching for these flightless females by scent rather than sight. This explains why, although the Pale Brindled Beauty is not uncommon, the females are very rarely seen and easily overlooked.

Chestnut Moth

It’s hard to see much moth trapping happening for the foreseeable future, though. The forecast is already hinting at more snow by the weekend, and Caithness doesn’t exactly forgive optimism when it comes to winter weather.

Standing in the cold, checking traps with numb fingers while Arctic air cuts straight through you, it’s easy to question your life choices. But moments like this—new species, unexpected records, and small signs of life pushing through winter—make it worthwhile. Even in conditions that feel more polar than Scottish, nature is still quietly getting on with things.

And sometimes, that’s enough to keep you setting the trap out one more time.