Let’s have a look at identification of early emergent butterflies in the UK. Of our nearly 60 species of butterfly, only 6 overwinter as adults emerging with the first warmth of spring sunshine to delight us with their colour and beauty. Of these half dozen, 2 species – red admiral and clouded yellow – have until recently been strict migrants; milder winters of late have allowed some to overwinter successfully especially in the southern part of the country. All other UK butterflies spend the winter as an egg, larva or pupa, emerging as adults much later in the spring or summer.
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Brimstone. This bright yellow butterfly spends the winter hidden in ivy and other evergreen shrubs. It is one of the first to take wing, often being seen on warm days of March or even February if the conditions are favourable. During 2019, a friend and I saw one at RSPB Strumpshaw Fen on 13th February which turned out to be the first one officially recorded that year. It is widely thought that the colouration of the male, a sulphur yellow, has given rise to the term ‘butterfly’, i.e. a flying insect the colour of butter. It is only the male that sports a bright yellow countenance; females are much paler and can be confused with the whites, especially later in the year when the summer brood hatches and overlaps with emergence of those other species. At all times the brimstone can be told apart by its very distinctive wing shape, the forewing having a pointed, slightly hooked, tip as opposed to the rounded tip seen on all other similar butterflies. The hindwing has a small spur. Unlike the whites and the clouded yellow, neither sex has any black on their wings, they instead have two small reddish spots which appear on upper wing and underwing.
Male brimstone feeding on Dame’s Violet – note the distinctive wing shape, sharply pointed at the wingtips of both forewing and hindwing. Note also uniform colouration, no black margins and small red dots on both wings. The eye is black.
Courting brimstones. Here the male is checking out the much paler female. Her posture is not, as would perhaps be understandably inferred, a ‘come on’, rather it indicates she has already mated and is not interested in further naughtiness!
Clouded Yellow. This species is widespread in continental Europe, North Africa and the Middle East. It is only traditionally seen in the UK as a summer migrant, sometimes in reasonably large numbers. In recent years, our warming climate and consequent milder winters has allowed small numbers to overwinter, although only in the southern counties of the UK. It is unlikely to be encountered anywhere other than southern England until a fresh wave of migrants reaches us in late summer. I’ve included it here for completeness. Clouded yellows can be told from the brimstone by their more conventional shape, much darker, mustard yellow tones and the extensive black margins to the forewing. At rest it shows a distinctive white spot on the underside of the hindwing with a series of small black dots on the forewing. This species is normally very active and nowhere near as likely to settle for long periods as with most other species.
I found these mating clouded yellows at NWT Cley Marshes in August a few years ago. The species can readily breed during our summer, but until recently has not been able to overwinter. Note the more conventional butterfly shape, the bright white circle in the middle of the underwing and the reddish markings around the wing edges. The eye is bright green.
Comma. A familiar species that is often encountered early in the year when it will feed on available blossom and catkins of willow. The ragged wing shape should be enough to identify the species and differentiate it from the superficially similar small tortoiseshell. Commas love to bask in the sun with their black spotted, deep orange wings fully open. At rest the distinctive white ‘comma’ mark is quite noticeable and of course gives the species its English name. Commas overwinter in piles of leaves, sheds, outbuildings or suitable cavities in trees, emerging on warm spring days. I’ve just been watching one nectaring on blackthorn blossom in my garden (26th March) and they have been noted around Norfolk over the past week or so. Later in the year they can reliably be found sipping the nectar of flowering ivy to which they flock in numbers. Late summer insects destined to overwinter have a different coloured underside from those that will see the summer out then die. The long-lived specimens have a uniform dark brown colouration whereas the shorter-lived individuals are lighter and more variably marked. I’m guessing this is an adaptation allowing better camouflage in those dark recesses chosen for winter slumber.
An early emergent comma feeding on flowering currant in my garden. These plants together with blackthorn and willow catkins provide an important source of early nectar. Note the very jagged wing margins and liberal array of dark brown blotches and spots.
Here you can see the bright white ‘comma’ mark on the underside of the trailing wing which gives the species its English name.
Commas, together with other autumnal butterflies, love feasting on the nectar of ivy. One good reason to ensure you leave some in your garden.
Small Tortoiseshell. One of our most familiar and widespread butterflies. When I was young, living as we all did in houses untroubled by central heating, we always had a few of these overwintering in cool bedroom cupboards or in the corner of the alcove by the back door. Spring sunshine woke them up and we would have to chase them around the window panes before catching them and releasing them outdoors. Nowadays, in our modern houses, there is seldom room for these handsome insects. Even if they do choose to attempt overwintering in our homes will be rudely, and probably fatally, be awoken mid-winter once the thermostat bites hard. We called them ‘The King George’, a term I haven’t heard used for a long time. Small tortoiseshells are a slightly richer shade of orange than the comma and have a much more uniform wing shape. The leading edge of the upper forewing is marked with alternate blotches of black and yellow. The margins of both upper wings are jewelled with blue spots. The underwing, as with all the non-yellow butterflies we are discussing are basically a mottled array of dark colours, although the underside of the forewing has a much more extensive lighter patch than the comma.
One of our most widespread and familiar butterflies, small tortoiseshells can be recognised by their orange colouration, blotches of black and yellow along the leading edge of the forewing and a margin of bright blue spots.
Peacock. Unmistakable and aptly named in honour of the yellow bordered, bright blue ‘eyes’ that bedeck the upper side of all four wings. The peacock is a rich crimson brown in colour variously blotched with black and with a row of white dots on the forewing. It is much larger than the previous two species and can frequently be disturbed from basking spots on dry open ground. The underside is very dark brown, almost blackish, which again aids concealment in dark wintering sites.
In spring peacocks will feed on bluebell nectar. Easily recognised by its bright blue eye spots which are thought to scare would be predators when the butterfly suddenly opens its wings when under threat.
As you can see the precise size and colour of the eye markings does vary but is always striking and unique amongst UK butterflies.
Red Admiral. This species is quite distinctive and has recently taken to overwintering in the UK as that season becomes milder. Specimens were reported very early in March this year from widespread localities, indicating that red admirals are now becoming an established year-round resident. The red bands set boldly against a jet-black background on the species forewing are diagnostic. The red markings flow round to the underwing which again differentiates it from all the other species we’ve considered here.
The red admiral is unmistakable. The bright red lines across the forewing and on the trailing edge of the hindwing set against a jet black background are diagnostic.
In about 30% of specimens (mainly female I believe) there is a small white spot in the red band – something to look out for as a bit of fun.
The underwing of the red admiral is quite similar to the upper side. The red markings are still quite noticeable.
Hope you found this guide to identification of early emergent butterflies in the UK helpful. Any feedback will be most welcome.
Test your knowledge now and take the Quiz. No prizes other than being able to bask in the warmth of being able to identify some beautiful early spring insects.
#1. What Butterfly Is This? ? Look for the bold black blotches along the leading edge to the forewing.
Sorry, that’s not right. This butterfly is a Small Tortoiseshell, otherwise known as a King George. Look for the bold black blotches and blue beading along the trailing edge.
#2. And This? ? Look for the jagged edges to the wings and the comma mark on the underside
Sorry that’s wrong. This butterfly is a Comma. Look at those jagged wings!
#3. What About This One? ? Brimstones are named after their colouration and are thought to have given rise to the word 'butterfly' in that they are a butter coloured fly.
Sorry, that’s not right. This is a Brimstone, it is an overall pale yellow with small brownish-red spots. There is also a noticeable angular shape to the wing.
#4. What's This One? ? Red Admirals have only recently started to overwinter in the UK. They are a migrant butterfly reaching us in numbers during summer and early autumn.
Sorry, that’s not right. This is a Red Admiral. Look for bright red markings on a velvet black wing.
#5. And Finally.... ? Named after the colourful 'eyes' on the wings
Sorry that’s not right. This is a Peacock, so named because of the colourful ‘eyes’ on the wings which are used to ward off predators.