Some, like painted lady butterflies, migrate south to warmer climates, others, such as ladybirds, huddle together for warmth, while many will time the stages of their lifecycle to ensure they spend the winter secreted away as an egg, caterpillar or pupa. However, some hardy moths can front out the season as adults by employing some very ingenious strategies. The first is alcohol…not swigging mulled wine and eggnog, but specialist alcohols inside their bodies that act like ‘anti-freeze’ to stop ice-crystals forming. They can also expel water from their system to prevent their insides freezing and also create their own body heat by vibrating their wings. These specialisms enable them to fly on cold nights and you may be lucky enough to catch sight of one.
(A Long) December
Like a 1920s starlet heading to Gatsby’s New Year’s Eve party, clad in folds of ermine fur and an ostrich feather headdress, the December moth is the epitome of winter insect style. Charcoal grey-brown in colour with cream markings and a wingspan of 30-45mm, they can be seen flying along hedgerows, in woodlands and gardens throughout November and December. With so few nectar sources around in winter, the December moths are incapable of feeding and instead have adapted to survive on energy stored during their caterpillar stage. This means they can focus all their time on finding a mate; their feathery antennae give them an excellent sense of smell for doing just that. Once mated, the larger females will lay their eggs on the branches and twigs of several broadleaved tree species including oak, birch, elm and hawthorn. The eggs will remain here through the rest of the winter with larva emerging in spring.
(In the bleak mid) Winter
Dressed in more understated tones of buff and biscuit and much smaller than the December moths, winter moths have a wingspan of 22-28mm and are widespread throughout Britain. The adults fly from October through to January or February and can often be found resting on tree trunks. Female winter moths are virtually wingless and cannot fly so must crawl up tree trunks and release pheromones in order to attract a mate. Small green caterpillars hatch in spring and feed on tree foliage; amazingly, they can also travel between food sources by spinning a silk thread and waiting for a breeze to carry them to the next tree – this known as ‘ballooning’ but perhaps a bet term might be ‘Tarzaning’!
Winter and December moths are attracted to light so hang a light sheet outside and shine a torch on it to stand a good chance of seeing one.
(Hark! The) Herald
Unlike the angels in the Christmas carol, you won’t hear herald moths, but you may find one hibernating, also known as overwintering, in sheds, garages or caves. Decorated with daubs of bright orange, their hooked forewings with scalloped edges are unmistakeable. The adults fly up until November and then enter a sleepy, torpid state for a few months before emerging early the next year. It is thought their name may have been chosen as they are usually one of the first species to be seen after the end of winter, thus heralding the start of spring.
Herald moths may try to hibernate in houses but will be disturbed by central heating. If you do find an insect taking shelter in your home, just carefully move it to an area with a more constant temperature, such as a shed or garage.
The Chestnut (roasting on an open fire)
With its thick, furry scarf, the chocolatey chestnut moth is another that seems dressed for the season. They can be seen any time between September and May but most often during mild spells over winter or visiting willows during spring. Its close relative the dark chestnut can also be seen in winter but less frequently and its flight period is shorter – October to March.
You won’t see antler moths flying overhead on Christmas Eve, pulling Father Christ-moth’s sleigh, as this species overwinters as an egg but they’re a visual treat in warmer times. Look out for them in the mid to late summer on grassland and moorland. Named after the distinctive, creamy antler-shaped marks on their forewings, they can often be seen feeding on flowers such as thistle and ragwort.
(A kiss beneath the) Mistletoe marble
Any stolen kisses at the Christmas party may well be witnessed by mistletoe marble caterpillars who spend the winter tucked away in this evergreen plant. Usually found on apple trees; they burrow into a leaf creating a small mine which keeps them safe until they are ready to pupate in early summer. Once hatched their party frocks are marbled in beautiful swirls of white, fawn and cobalt blue, however, these colours are actually a disguise to discourage predators as it makes them look like bird poo! Despite this trickery, numbers have declined significantly, and the mistletoe marble is now only found in six counties in western England.
With over 2500 moth species in Britain there are many more with seasonal names, but the nutmeg, currant clearwing, Hebrew character and many more will have to wait for another day. Keep an eye out for moths this winter and do let us know if you spot any.
London Wildlife Trust has partnered with the Natural History Museum and Butterfly Conservation on the Brilliant Butterflies project which is creating and restoring butterfly and moth habitat across South Croydon and Bromley, thanks to players of the People’s Postcode Lottery – find out more here: https://www.wildlondon.org.uk/brilliant-butterflies