On Friday 14th January, I took a lunchtime walk down to the Taff riverbank in Cardiff on the off-chance of seeing an early butterfly. After an overnight frost it was still rather chilly, but pleasant enough in the midday sun. I’d seen reports of Red Admirals, Peacocks and Small Tortoiseshells on the previous few days, these being the species most often seen in January as they spend the winter as adult butterflies, meaning they can rouse themselves on any suitably sunny day. The only other butterflies regularly seen in January are Comma and Brimstone, which also hibernate as adults, and occasionally an early Painted Lady arriving from overseas.
So I had to do a double take when I spotted a medium-sized brown butterfly flitting above a bramble patch, its flight pattern clearly different from the flap-and-glide of the Vanessid butterflies mentioned above. It was a Speckled Wood, a butterfly I’d never seen earlier than the last few days of March. It flew strongly, considering the temperature, then spent a few minutes basking on the brambles, allowing me to get some photos as featured in this blog.
Speckled Woods can overwinter as a caterpillar or a chrysalis, with those that fly in early spring being the ones that overwintered as a chrysalis. The individuals that spend the winter as caterpillars fly later in the spring. January sightings of Speckled Wood are not unheard of, but these are usually from the far south-west of England where winters are mildest. I had a look online for recent records and discovered the first sighting in 2022 was two days earlier than mine, in Cornwall, with one also seen in Devon the following day.
Though it’s always nice to see a butterfly, the early emergence of Speckled Woods is probably bad news for the species, and is likely to be due to climate change. The butterfly I saw had likely spent the first part of the winter as a chrysalis, but had been fooled into thinking it was spring by the exceptionally mild temperatures around the New Year. Indeed, New Year’s Day was the warmest on record. It takes a few days for the butterfly’s wings to colour up inside its chrysalis shell, and then it probably just needed a bit of sunshine to trigger it to emerge.
Early butterflies such as this one will struggle to find any nectar, and a sudden deterioration in the weather could see them perish without having had chance to mate and lay eggs. The adult hibernators can return to their slumbers in an outhouse, log pile or hollow tree, though they may use up valuable energy reserves in the process.
