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August butterflies and insects

Other August pages: Fruits, berries, nuts and treesDownland and seaside flowersWayside flowers BirdsWeather

Picture: adonis blue butterfly. Click here for more August butterfly and insect photos. For more information on butterflies and moths see the Butterfly Conservation website.

The number of butterflies reduces sharply during August. Early in the month you can still see plenty on sunny days in places where there are flowers for them to feed on. As the month goes on sightings become more infrequent, or confined to a few favoured hotspots (in particular on coastal parts of the Sussex downs).

At the start of the month you may just see some marbled whites on grassland and downland but they are definitely on the way out, while ringlets have disappeared entirely. Gatekeepers are to be found around hedgerows and bramble only in the first half of the month (just possibly into the third week).

Large, small or Essex skippers are only seen in the first few days of the month, if then. On short turf on some downland slopes in the south east (try Brockham Quarry or the southern slopes of Box Hill or Ranmore Common), they are succeeded by the silver-spotted skipper, for which this is the best month. The very localised Lulworth skipper, found only on the hills above and around that Dorset cove, can still be at its peak at the very start of the month and is potentially visible till its end.

Otherwise, in hedgerows a new generation of peacocks appears in the second half of July and some of these usually remain on the wing into early August, weather permitting. These are the offspring of the butterflies which appeared in March or even late February and will go on to hibernate (or, to be more accurate, diapause - a complete cessation of metabolic activity) over the winter, appearing again in early spring to breed. If you want to see them diapausing, the dark corners of World War II pillboxes on the North Downs are one place to look - but if you find them there please do not disturb them.

In the second half of August there can in theory be a new generation of small tortoiseshells, the offspring of the ones that appeared in late June and early July. But this once common butterfly has seen significant declines in the south east in recent years, one problem apparently being a parasite that feeds on their caterpillars in the summer months. Essentially, since 2014 there have been almost none seen in August, apart from a slight uptick in numbers in 2019 and 2021. Any small tortoiseshells you do see at this time of year - and any from the June to July generation that fail to breed - will go into hibernation to appear in the spring.

At a casual glance it is easy to mistake a small tortoiseshell for the painted lady, a butterfly that migrates in several generations from Morocco in favourable summers, and is a bit more common near the south coast, though also found inland. In many years one sees hardly any (for example 2017, 2018, 2020, 2022 and 2023), and in others only a few (2021), but every now and then there is a year when they are quite numerous. A famous example was 2009, when they were apparently everywhere, and the same effect was seen in the north of England in 2019. In the south east that year numbers were fairly good but not spectacular.

Another migrant - and one that is quite common some years (2017 being an excellent year, 2023 good from July onwards, 2021 fairly good, 2019 and 2022 less good, and 2018 and 2020 very poor) - is the red admiral, seen in and around hedgerows. From mid August some are starting to head south again but they remain widespread into the autumn and some even spend the winter here. Males are often patrolling a territory, so if you disturb one, stand still and it may well come back.

On downland, particularly near the coast, you may also be lucky enough to see another migrant, the clouded yellow. It has a hint of orange in its upperwing and flies past very fast. If it settles, it closes its wings, showing only its green-yellow underwing. A few breed here each year, and their offspring start appearing later in August, which can boost numbers in favoured spots.

Clouded yellows are not to be confused with the much commoner brimstone, a native yellow butterfly with a bright yellow upperwing, which also closes its wings when it settles, revealing a lime green underwing with a very characteristic shape. A new generation of these emerge in July and a few may still be on the wing in the first half of August (rarely into the third week). Those that you see will be very long-lived, hibernating over the winter and lasting as adults until June in some cases. Contrast this with some other butterfly species (common blues, for example) that may only live a few days.

If you see a flash of orange in the hedgerow, it is most likely to be the striking comma, another butterfly destined to hibernate over the winter. With their wings closed they look just like a fragment of dead leaf, but in hotter summers a variant is produced in early July with more orangey underwings: these go on to produce a further generation later in August. In such years, ones you see at this time of year could be survivors from July or new adults. In either case in August they are in display mode, perching prominently with their upper wings open, and feeding (apparently) on blackberries. Like red admirals they often swoop back and forth across a particular spot, returning to the same perch you disturbed them from.

Easily the most widely seen butterflies in August, however, are the large white, small white and green-veined white, commonly called cabbage whites. At the start of the month they can seem to be everywhere - in gardens, on hedgerows and verges, and flitting across arable fields. Numbers then decline noticeably, but it is a rare day even at the end of the month when you don't see at least a handful of them. (In some years, eg 2019 and 2021, this seems to be reversed, however, and there are relatively few early in the month and an uptick - at least in small and large whites - at the end of the month.)

As for which of the three species you are seeing, it is hard to tell, since they rarely seem to rest. But if they do come to a stop, the green-veined can distinguished from the other two by the green veins on the underside of its wings, while the large white has larger and blacker wing tips which extend equally along both wing edges. Particularly in the early part of the month some apparent large whites may in fact be female brimstones, which are a pale green-white colour. The shape of the closed wing when at rest should settle the matter: brimstones also never rest with their wings open.

In woodland, the most common butterfly is the speckled wood, a dark brown butterfly with yellow spots, which can be seen throughout the month. They are well camouflaged in this habitat but have a gratifying habit of basking on a sunny leaf, making them easy to see or photograph. This is another butterfly that often returns to its original perch if disturbed.

In the early part of the month you may also see the magnificent orange silver-washed fritillary in clearings near woodland - for example, feeding on buddleia or any remaining bramble flowers - though they tend to be looking rather tatty by this point. In sunny summers you may also see some wood whites in the first half in and around Oaken Wood near Chiddingfold in Surrey, where they have a partial second generation: their small size and flaccid flight distinguish them easily from other white species.

In theory both the magnificent purple emperor and the much smaller but still impressive purple hairstreak butterfly can also be seen this month, but they live in the top of oak trees and are only spotted on rare forays to the ground (in the case of the purple emperor to imbibe minerals from soil or animal faeces). Also living in tree tops, though this time on ash, is the brown hairstreak, for which August is the best month. With this species, the key is to catch females on fine sunny days coming down to lay eggs on blackthorn bushes or to feed on bramble, thistles or hemp agrimony. But they are very elusive butterflies and you have to have sharp eyes (look out for what looks like a tinted leaf) and be lucky in your timing.

On downland and in other grassland meadow brown butterflies can still be seen throughout the month, but in lower numbers - or smaller pockets - than they were in July. Much more exciting is to see the tiny flash of blue that is the male common blue, which is well-named as it is by far the most common blue butterfly that you are likely to see. It is usually found on downland, but sometimes in other grassy places.

Having said that, near hedgerows (and particularly around ivy) the holly blue is also a distinct possibility, as it produces a second generation in late July which is on the wing in the first three weeks of August, or even till the end of the month some years. You can distinguish it from the common blue by its habitat and by the fact that it flies at waist or shoulder height, while common blues are always seen low to the ground on grassland. The undersides of the holly blue's wings are also light blue, while on a common blue they are beige. Numbers of this butterfly vary greatly from year to year: 2023 was a very good one for them.

On flower-rich south-facing downland in the second half of August a further possibility is the adonis blue, which produces a second generation at this time. However, this is a butterfly that is only found in certain locations, for example the lower slopes of Ranmore Common near Dorking, Yoesden Nature Reserve near Saunderton in the Chilterns, or Mill Hill Reserve and Anchor Bottom near Shoreham-by-Sea.

The adonis likes south-facing downland slopes and looks almost identical to the common blue, though if you see the two together you can see that the adonis has upperwings of a brighter, lighter shade of blue. (Be careful, though: seen in isolation, the common blue's also look light and bright). If you get a closer look, the adonis has tiny dark lines through the white border of its wings (though common blues also have slight dark marks on the inside edge of the border: often only a photograph settles the matter). The underwings of the adonis are also a more chocolatey brown than those of the common blue.

Much easier to see on flower-covered chalk downland - try the southern slopes of Pewley Down near Guildford, Castle Hill nature reserve near Lewes, the lower slopes of Ranmore Common, or the downs above Otford and Shoreham in Kent - is the chalk hill blue, which is bigger than the adonis or common blue and somewhat paler. It can look almost white in flight, but is clearly blue when you see it at rest - and has black veins and distinctive black edging to its upperwings. Populations of this butterfly are at their best in the first half of August, when you may see several hundred in favoured spots.

The holly blue apart, the females of all these blue species are all brown, with orange dots of varying intensity around the edge of their wings. Differences between them are subtle, and if you see a tiny butterfly fitting this description it might be a brown argus (see the July butterfly page for more discussion on this), which is on the wing all month.

While the brown argus is mainly seen on downland, it can also be seen on heather-covered heathland in August. Another butterfly of this habitat which is at its best this month is the grayling, a butterfly so well camouflaged that it can be a metre from your face and you can't see it until it moves. Adding to its elusiveness, in this part of the world it is found only on a few Surrey heaths (try Dawney Heath near Purbright, Chobham Common, or Frensham Common near Farnham): also Stoborough Heath near Wareham, Dorset.

One last blue butterfly, which is not native to the UK but which seems to make increasingly regular incursions into southern coastal areas in August (sometimes further inland too) is the long-tailed blue. It has very distinctive striped underwings, which are the aspect of it that is usually seen. The upperwings are of varying shades of blue and brown, sometimes almost purple. Females will search out broad-leaved everlasting pea to lay eggs: males will feed on seaside plants such as tamarisk and red valerian while they wait for females to turn up. Whitehawk Down in Brighton seems to be a good place to find them, as is Lancing Ring on the downs behind the coastal town of that name.

Back on grassland, a tiny butterfly - orange in flight, but only ever seen at rest with its wings closed - is the small heath. In photographs it looks quite similar to the meadow brown or gatekeeper in this pose, but its minute size makes it easy to distinguish from these two. It is also always close to the ground, never being seen above a metre or so in height. A new generation of these butterflies is usually emerging as the month goes on, so you are more likely to see them at the end of the month.

Another tiny butterfly with orange and red markings that you may just see during August is the elusive but very striking small copper, which can crop up in all sorts of habitats, but which seems to particularly like (or be particularly visible when) feeding on ragwort flowers.

Meanwhile, if you see a medium-sized butterfly with black and orange markings like the comma, but with an eye on each wing, it is a wall. This butterfly, which can also look like a very fast-flying meadow brown when on the wing, is found only on scrub and grassland near the south coast. Try Portland Bill or Swyre Head near Kimmeridge in Dorset, the cliffs between Dover and Kingsdown, Folkestone Warren, the downs above Shoreham-by-Sea (eg Anchor Bottom and Mill Hill), Lancing Ring, High & Over Hill near Alfriston, the shingle area between Seaford and Newhaven, or the area behind Belle Tout lighthouse near Eastbourne. New ones can still be emerging even late in the month and they last into September.

Exceptionally in the first week or so of the month on downland you may also see a dark-green fritillary - usually a tatty female survivor from July - and at the same time look out for the very small second generation of the dingy skipper whose nondescript brown markings make them easy to mistake for a day-flying moth.

Day-flying moths

There are still a good number of day-flying moths flitting about on verges or in flowery grassland in August - in particular the tiny white grass moths which snap shut into a thin line as soon as they land making them almost invisible. Early in the month you might also see the striking six-spot burnet with its red on black spots, which is particularly fond of knapweed and ragwort flowers. Also very striking, and an increasingly common sight in the south east (especially in 2022), is the enormous Jersey tiger, which can turn up in gardens as well as wilder places until the third week or so.

You also continue to see - or disturb - various small white moths on path verges and downland - for example the common carpet, chalk carpet and lace-border, the latter found only on the North Downs of Kent and Surrey. The treble bar, fairly common on downland, has grey stripes.

Other day-flying moths you may see include the yellow shell and shaded broad-bar, as well as the tiny mint moth - the latter found particularly feeding on herbs such as marjoram, and also known as a small purple and gold after its colourings. In addition I have seen a snout, blood vein, pretty pinion, flame shoulder, small waved umber, straw dot, footman and clouded buff during August, some of these being night-flying moths which one inadvertently disturbs when walking past during the day.

The month can see an influx of silver Y moths, a migrant which can arrive in quite some quantities on the south coast, particularly on downland, though also in other habitats, and which are especially active later in the afternoon. They are large - about the size of a meadow brown butterfly - and greyish with white markings on their wings, but their constant buzzing flight makes it hard to see this.

Also on the south coast - the seafront gardens of Eastbourne, Folkestone or Broadstairs seem to be good spots - you may be lucky enough to see the enormous hummingbird hawkmoth, a migrant from Southern Europe, which seems to be particularly fond of feeding on red valerian flowers, and which, as its name suggests, uses its long proboscis to feed on flowers while hovering in the air. 2022 was an excellent year for them, when they were regularly seen all over the south east.

Insects fade slowly

Insects slowly become scarcer during August, as they die off, get eaten or become dormant, but the process is hard to quantify and depends somewhat on the weather. A hot sunny end to August can prolong insect lives - so long as there is not too much of a drought - or a cool, changeable one bring them to an early end. In places where there is a good nectar source you can still get a good concentration. There is also no doubt that you can see some insects right to the end of the month, and indeed throughout September. But if you compare their general frequency at the start and end of the month, there is a noticeable reduction - a real sign that summer is coming to an end.

You can still see bumble bee workers even late in August (particularly the common carder bee, which lasts into September or even October), but numbers are definitely declining as the weeks pass, and you are increasingly likely to see new queens, which are noticeably larger (although care is needed here because some bumble bee species are larger than others). One clue to identifying queens is that they are less obsessive about visiting flowers, since they only have to feed themselves rather than collecting pollen for the colony.

The same is true of males, who are produced around this time, and lead a nomadic lifestyle, having no nest to return to. They are sometimes seen sleeping on flowers. The queens mate with the males, and then need to find a hole to spend the winter in, so you can often see them flying close to the ground. Their buzzing often alerts you to their presence. All but the new fertilised queens then die off in the autumn.

Honeybees live in colonies all winter - they make honey to keep themselves fed - so they can still be seen out in force wherever there is pollen and nectar for them to collect. Solitary bees overwinter as adults or as larvae, depending on species: some are still around in August.

Identifying solitary bees is hard, however, because many hoverflies have also evolved to look like bees - for example, the common or tapered drone fly. As the month goes on the number and variety of hoverflies definitely declines, but you can still see them occasionally right through September and even into October, depending on the weather and the nectar sources available. Close-up, many hoverflies have beautiful patterns on their bodies, some of my favourites being the footballer, the marmalade and syrphus varieties. Note also the large hornet mimic hoverfly, which looks as alarming as its name suggests, but is perfectly harmless.

Wasps were once an exception to the general decline in insects, becoming a nuisance to humans eating outside in August, buzzing around our picnics, pub lunches or cream teas. In recent years, however, this has become alarmingly rare, with only one or two seen at a time.

The explanation for this traditional August outbreak of wasps is that these are workers, who earlier in the summer live in colonies, feeding their collective larvae on a diet of crushed insects: they in turn are fed by sweet secretions produced by the larvae. But as the summer draws to an end the young queens and males fly off to mate, and the colony breaks up. The workers, now redundant, go off in search of rotting fruit, nectar and other sugar-rich foods. After this pleasant retirement, they die off when the cold weather comes in the autumn.

Flies in all their various guises reduce in number in August but if you look closely at a bramble bush covered with ripe blackberries earlier in the month you may see quite a lot of them. Cattle also continue to attract them and in general there are still fair numbers about even at the end of the month, when ivy flowers start to become a favourite food.

Likewise early in the month the air is still filled with tiny unidentifiable tiny flying insects but they become an increasingly rare sight as the month progresses. You see some on hawkbits, dandelion and other flowers, along with the occasional swarm of gnats. By late August your arms and legs no longer get covered in midge bites, and a lot fewer insects invade your house if you leave a window open.

In contrast to all this, there are some bugs that are only just emerging as adults in August, their parents having mated in spring and the offspring having spent the summer as larvae and then pupae. An example is the dock bug (often seen on blackberry bushes, because they like to feed on them) and the seven-spot ladybird.

Towards the end of the month they are joined by a new generation of shield bugs - for example, the green shield bug. All of these feed up in the late summer sun and then hibernate to breed next year. By contrast the invasive harlequin ladybird has been active and breeding all summer - an advantage it has over native ladybird species which breed only once a year. This led scientists to worry in the 2010s that they would replace our native species. But since 2020 they have (in the author's anecdotal experience) been almost entirely absent, so perhaps the invasion has come to an end.

Crane flies, grasshoppers and crickets can still be found in grassland all month. You often only notice them when they jump or fly away from your feet as you walk across a field of tall grass. Ants continue to be active above ground all month and you may see an eruption of flying ants: this is the mating ritual of the black garden ant, where the queens and males fly off to mate, after which the new queens look for somewhere to found a new colony.

Huge numbers of ants participate in these events: sometimes the cloud is so big that it can be seen on weather radar. They can appear like masses of flying seeds, or you may encounter them on a sea swim looking like lots of dead flies in the water (though if you fish them out, they are not always dead...). Being unused to the air, they are sometimes quite clumsy fliers

There continue to be lots of spiders hidden away in grass and among plants. The early morning dew in late summer means you can see the threads money spiders make as they "balloon" - that is attach their threads to a blade of grass and then use air currents to carry them across a field. They do this in order to avoid mating with their siblings, and one field can have millions of threads. You can also see the funnel-like webs of labyrinth spiders in grassland, as well as fearsome-looking wasp spiders, which can trap large prey such as butterflies.

In gardens, spider's webs become a lot more prominent as the month goes on. This is because spiders who have been growing all summer now reach adulthood and are looking to lay eggs. Female garden orb weavers (including the distinctive garden cross spiders with a cross on their back) are often the ones making these. They are active at night, building their webs in the pre-dawn hours, and since they don't stay sticky for long, they have to be remade every day or two - a task which only takes about half an hour, the spider consuming the old web as she goes.

Pondskaters can still be found on the surface of still water, and you may just see a damselfly (often a common blue) or a banded or beautiful demoiselle, most likely early in the month, but sometimes later. A new species of damselfly, first recorded in East Anglia in 2009, and now spreading across the country, is the willow emerald: it is possible all month and can fly into September and even October. Though a deep metallic green, it can seem brown in certain lights. One easy way to distinguish it from other damselflies is by its habit of holding its wings at an angle to its body when at rest.

Dragonflies continue to hunt unabated, with various species to be seen. Identifying them is difficult because they rarely stop to rest and have 360 degree vision to spot you if you try to get close. But common darters seem to be particularly conspicuous at this time of year, the male with a bright red abdomen and the female more yellowy. There is also a ruddy darter, also with a red abdomen, but tapering more in the middle: it is particularly fond of woodlands. The large southern hawker (black and blue tail, with a green and black thorax) and the similar but smaller migrant hawker are also fairly common. The striking blue emperor, our largest dragonfly, may be seen early in the month.

More August pages:

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