Forget birdwatching, I’m into moth-watching: they’re fascinating and misunderstood insects | Helen Pilcher

Do have you ever worried that your brain would slow down and your mind would be…what’s the word…foggy? If so, I have news. A recent birding study, led by aptly named lead author Erik Wing, found that learning to become an expert birder causes changes in the brain that may help protect against age-related cognitive decline. Compared to beginning birders, when real bird enthusiasts distinguish difficult species, they show more activity in brain regions related to visual processing, attention, and working memory. These same areas also appear more compact and age-related changes are weaker.

The take-home message is that learning to distinguish a chiffchaff from a willow warbler could help us stay mentally sharp as we age. But what about the distinction between a common Quaker and a darkened drab? Or a brown-lined bright eye from a bright-lined brown eye? These are not the names of birds, but of moths. I have been addicted to butterflies since I was a child.

At the risk of alienating an entire community of wildlife enthusiasts, birds are the lowest-hanging fruit. Moths are orders of magnitude more difficult to distinguish. As part of a citizen science project called the Garden Moth Scheme, I regularly install a moth trap in my leafy garden. The devices, which can be purchased or DIYed, use light to attract moths, which then stumble into the body of the trap, where they remain unharmed until morning.

Most weekends, you’ll find me hunched over my field guide, sifting through the contents of my trap before gently releasing my captives. There may be 636 species of British birds, but there are four times as many species of British moths. These are divided into two groups: the larger “macro” butterflies (900 species) and the smaller “micro” butterflies (1,600 species). The wingspan of Britain’s smallest bird, the goldcrest, is roughly the distance between the index finger and the thumb. The wingspan of the smallest British butterfly, Enteucha acetosaeis shorter than a grain of rice.

At the height of summer, when butterfly numbers peak, my trap is teeming with hundreds of butterflies from dozens of species. Some species are so similar to others that they are set aside only by the smallest detail – the curve of a forewing or the architecture of an antenna. What makes things even more confusing is that members of the same species can sometimes look very different, with varying wing colors, or sometimes no wings at all. Reflecting these difficulties, the Victorian naturalists who named many of them did so with a wink. There is a butterfly called the confused one and another called the uncertain one.

If you listen to the haters, moths are all drab pests, flying at night and nibbling on clothes. Not true. Some moths, like the elephant hawk, make Elton John’s stage outfits look tame. In the UK there are more species of moths than butterflies, and the larvae of only two species of butterflies will munch on natural fibres, such as wool and cashmere, but even they cannot eat an entire sock.

Moths are much maligned and misunderstood, but they play a vital role in the natural world, where they pollinate plants, provide food for wildlife, and contribute to the cycling of nutrients between life and the earth. They are also harbingers of environmental changes.

The Garden Moth Scheme has been in operation nationally since 2008. More than 1,000 loggers have provided their data, revealing a worrying trend. Half of our moth species are in decline. This tells us that the balance of the natural world is out of balance.

I love butterflies for many reasons: for their central place in our terrestrial ecosystems, for their often understated beauty, for the mindfulness they instill when I focus on their form, and for their stubbornness in the face of easy identification. I love them because they are constantly surprising. The Chinese character resembles a small bird poop, tiger moths emit ultrasonic clicks to jam the sonar of their bat enemies, and the death’s-head hawk moth mimics the scent of bees so it can plunder honey from their hives.

I don’t consider myself an “expert mother,” but I try. Every year, I decipher new species, while reconnecting with the garden’s most frequent visitors. Extrapolating from the world of birds, Wing’s research suggests that this time could be well spent. So now I have another reason to appreciate moths. With every properly graded footman, rustic, and rug, I support my brain health.