What’s the difference between a moth and a butterfly?

RSPB England's Lucy Hodson explores the differences between the two very similar-looking species.

What's the difference between a moth and a butterfly? It’s a common question, but how many of us know the answer?

The time of day? You might think it’s obvious – moths come out at night, and butterflies in the day.
Unfortunately, this isn’t as clear cut as it seems – some amazing moths, like the jazzy emperor and hummingbird hawkmoth, are exclusively day-fliers.

The colour? Moths are brown, and butterflies are colourful, aren’t they? Again – they don’t follow the rules! Look at meadow brows, speckled woods – and the unfortunately named dingy skipper. All butterflies! Elephant hawkmoths, five-spot burnets and the scarlet tiger moth – they give any butterfly a run for their money with their bright colours!

So, what’s the difference?

The answer is, the line between butterfly and not-butterfly is a very blurred one. Both groups form the family of lepidoptera; hugely diverse and with a great number of species. Though it may be tricky, in the UK there’s one neat trick. Butterflies have clubbed antennae, and moths do not!

Following this, we’ll introduce you to three of each gang; some common moths and butterflies you could encounter over the next few weeks!

Each year, the first few days of sunshine seems to flick a switch, where bucket loads of butterflies drop out of the sky in search of some springtime nectar.

Butterfly watch

So which butterflies might be some of the first to spot in spring?

Brimstone, Gonepteryx rhamni

Credit: Dorothy Moore

One of our earliest butterflies to emerge is the brimstone– appearing early in the year in an almost neon-yellow burst! The adults will have hibernated over winter, ready to take flight again on the first few warm days.

The females are a greenish-white, but the males are where the naming of the brimstone becomes obvious - a vivid butter-yellow. Some people believe the brimstone is where the name ‘butterfly’ originated from!

Brimstones caterpillars are quite fussy, and can only feed on one of two species; alder buckthorn (Rhamnus frangula) and common buckthorn (Rhamnus carthartica). The adults are less so – feeding on the nectar of many early spring flowers like coltsfoot.

Small Tortoiseshell, Aglais urticae

Another butterfly early to be on the wing is the beautiful small tortoiseshell. Like the brimstone, adults will hibernate over winter – so you might get some emerging as early as January or February if they warm up enough.

Identified by their marmalade wings and powder blue trim – they’re beautiful butterflies that have suffered a significant decline in recent years. They benefit from hot, dry summers, so it’s thought increased rainfall from climate change is one factor contributing to this loss.

Orange tip, Anthocharis cardamines

Credit: Lucy Hodson (butterfly and egg)

Finally, it’s the turn of the orange tip! These dimorphic butterflies are a true sign of spring – appearing in swarms on the first few warm days of early April.

The males, with their orange-tipped wings stand out brilliantly in the sunshine. The females lack the orange, but both have an amazing mottled underwing – camouflaging them brilliantly against the foliage they sit on.

If you see a delicate cuckoo flower this spring, consider taking a closer look! Females will almost exclusively lay their tiny, single orange eggs on this plant. If you look very carefully, you might be able to make one out!

So, what about moths?

If you learn how to search, you’re actually much more likely to encounter a moth than a butterfly in the UK. We have over 800 species of ‘macro’ moths (typically larger ones), compared to the 59 species of butterfly recorded here.

Cinnabar moth, Tyria jacobaeae

Credit: Dorothy Moore 

We’ll start with a vibrant day-flier, the cinnabar. This ladybird-schemed moth is seen out on sunny days, identified by the bright red stripes down its black wings.

Its caterpillars are also iconic, sporting black and yellow stripes to warn predators of their toxicity. Keep an eye out for them later in summer, when they devour ragwort in their hundreds.

Green longhorn moth, Adela reaumurella

Credit: Ludy Hodson

One of the fairy longhorn moths (yes, a real description) the green longhorn is a miniature but magnificent moth to spy! The males are a glittery metallic green and sport some borderline-ridiculous antennae – reaching about four times the length of their body.

Again, these dazzlers are day-fliers, and can be seen on warm spring days glittering in clouds. Their caterpillars feed on oak, so keep your eyes on branches in woodland areas, where big swarms of the adults can occur!

Peppered moth, Biston betularia

Credit: Lucy Hodson

This gorgeous monochrome moth is just one of hundreds of species you could meet if you delve into the world of moth trapping. This non-lethal pastime involves attracting moths using special bulbs and wavelengths of light.

Its mottled colouring makes the perfect camouflage as it rests on the silver bark of birch trees. Speaking of colouring – it has a fascinating relationship with human history. During the industrial revolution, a darker morph become more dominant as the soot coating birch trees meant lighter ones stuck out like a sore thumb to potential predators!

If you’re interested in moth trapping, take a look at the RSPB’s Luke Phillips recent video. Luke RSPB England's Direct Marketing Manager who spends much of his spare time exploring the fascinating world of moths. Join Luke as he delves into his moth trap and uncovers the species lurking within!