Thanks to volunteer Phil for his article and photos. We're expecting a sunny weekend and there are plenty of butterflies to be seen out around the nature trails.
This article was first written for the Staff and Volunteer Newsletter in the first weeks of Lockdown 1 in 2020. With all the recent fine weather bringing out plenty of butterflies I thought it would be appropriate to revisit this for the blog. Two years ago, while out on my lockdown walks in beautiful sunny weather, several people with little knowledge of butterflies stopped and asked what I’d seen and this revised article is written with similar readers in mind.
The original article was illustrated with photos taken close to where I live on the North Downs but all the species introduced here can be seen at Pulborough Brooks at this time of year. For this revision I am using a mixture of local photos and others taken at Pulborough to illustrate the same set of species.
Early spring butterflies are largely ones that favour gardens and sunny areas where there are nearby shrubs, trees and wayside flowers. Butterflies of more open countryside tend to emerge later in the season.
To understand butterflies better it helps to know not just their appearance and size, but what the adults and their caterpillars feed on. The latter is called the foodplant. Many adult butterflies feed on flower nectar but some use honeydew, a sweet substance secreted in trees by aphids. Some perch on bare ground from which they can ingest useful minerals. In autumn they use overripe fruit. Caterpillar foodplants vary widely from grasses through wildflowers to shrubs and trees, but some species are very restricted about these, which may cause problems if the foodplant declines.
The bright yellow brimstone
Often the first spring butterfly to be noticed is the large lemon-yellow male brimstone with its unusual scallop shaped wings. Its bright colour is unmissable. This restless insect always perches with wings folded to reveal pale green underwings which combine with the wing shape to help perfectly camouflage the butterfly when roosting or hibernating in foliage.
It is thought that the male brimstone may be the origin of the word butterfly as it is indeed butter coloured.
The more secretive females appear white but are actually a very pale green. In full sun they can easily be mistaken for the large white butterfly which appears a little later in spring. I managed to catch this one in mid-flight with wings fully open. It’s not often you see brimstones like this.
Brimstones have just one brood per year starting to lay eggs in spring which eventually emerge as adults in late summer and then hibernate throughout the winter. Adults can be seen in many months of the year, but the peak times are in spring when the hibernating adults emerge and then in late summer and early autumn when the new brood emerges to feed avidly on nectar to build themselves up to survive the winter.
The brimstone foodplant is purging buckthorn, a hedgerow shrub or small tree of scrubland with oval leaves and clusters of black berries later in the year, which grows well on the chalky soils of the North Downs close to where I live. Its name refers to its old use as a laxative as its leaves and berries are mildly poisonous. The very closely related and similar alder buckthorn which grows better in damp soils is also used and these may account for the brimstone population at Pulborough.
Hibernating stinging nettle users
Next a group of butterflies which hibernate as adults in winter and emerge in early spring which all use stinging nettles as their foodplant. First is the peacock, with staring eyes designed to deter predators.
It has very dark underwings allow perfect camouflage when perching on tree trunks and hibernating in dark places such as garden sheds over winter. It usually has a single brood each year which starts to emerge in July.
Second is the comma which has strange, ragged wings thought to help disguise adults spending the winter amongst leaf litter.
It has 2 broods that emerge in late spring and late summer. The first of these broods tend to show a lighter orange colour on the upper wings than the later brood so the commas seen in early spring are more likely to the darker overwintering form. This photo shows a lighter coloured form from the late Spring brood.
Looking back through my photos over several years however suggests that there may be exceptions to this rule, particularly with the overwintering commas.
The comma derives its name from the only white marking on the otherwise very drab under side of the wings as seen in this photo.
Third is the small tortoiseshell which has very pretty upper wings but in common with other butterflies in this group, very drab under wings helping it to stay hidden during winter hibernation.
It also has 2 broods, emerging in early summer and early autumn.
Last, the larger red admiral with its striking black, white and orange/red upper wings, is unusual in that most of the population throughout the year consists of migrants coming from the continent. It appears that some butterflies are now overwintering in the south of the UK and this can account for sightings in the early months of the year in warm spells of weather
Red admirals have one brood per year but the timing is spread out so there is never a gap in the period from spring through to autumn when the adult butterflies disappear.
All these nettle using species can often be seen perching on bare ground in full sun with wings either fully open or folded. If you see one with folded wings check to see if they are pointing towards the sun, a tactic to stop the butterfly becoming too hot.
Honeydew feeders
Most butterflies are sun lovers, but some will tolerate more shade. Two early spring butterflies feed mainly on honeydew and are therefore more associated with shady trees and shrubs. First, the holly blue is most often seen fluttering around trees or shrubs or perched on leaves. This lives up to its name and uses holly as a foodplant. Only rarely does it perch with open wings, but this photo shows some of the black edging to the upperwings visible when it does.
This wide black edging denotes a female. Males have much thinner black edging.
Second is the speckled wood, often seen on the ground, which uses a variety of grasses as foodplants.
Males are often seen sparring together in a spiralling fashion.
Both holly blues and speckled woods spend the winter as a chrysalis from which adults emerge in early Spring. They both go on to have 2 broods in spring and late summer.
The cheery orange tip
Finally I must mention my favourite UK butterfly, the orange tip. This common restless springtime wanderer along sunny woodside paths is largely white, but the males have a bright orange tip to the forewings. This looks cheerful to us, but is intended as a warning sign to predators.
Females can easily be confused with the small white butterfly which emerges a little later in spring but do overlap. However they can be identified by looking for the dark grey or black wing tips where the orange would be in the male.
The orange tip feeds on a variety of wayside flowers some of which, e.g. cuckooflower as seen in the male photo above, and garlic mustard, are used as foodplants.
While we appreciate the bright splash of orange the real beauty of this butterfly Its real beauty however is the amazing green and white camouflage pattern underneath its hindwing. When it perches on certain types of umbelliferous plant such as cow parsley it folds its wings to become completely camouflaged.
Sadly, the orange tip normally has only brood per year, surviving the winter as a chrysalis and adults disappear by early June. Enjoy these lovely cheerful butterflies while you can!