Month: June 2026

We are having a bizarre year for weather, and this erratic weather might become embedded, becoming the climate. We had extraordinary rainfall in January, February and March, and record heat in May, with the record for that month broken twice by more than 2 °C.  The highest air temperature ever recorded in Ireland in May was 30.6 °C on 26 May, at Shannon Airport. A heat wave was also recorded in June, when maximum temperatures again exceeded 30 °C.  Regarding winter rainfall, Dublin Airport’s February rainfall was 255% above the long-term average and the highest since rainfall records began 84 years ago. February and March temperatures were above average, but January was both wetter and colder than usual.

This meteorological background raises questions about how butterflies respond. Extreme heat in summer is beneficial for the adult and pupal stages and extreme precipitation has been found to damage the pupae (especially) and larvae of single-brooded butterflies (most Irish butterflies (21 out of 35) are single-brooded, i.e., they produce one generation each year).

The single-brooded butterflies are especially sensitive to extremes of heat and cold; the adult is sensitive to extreme cold in summer and extreme heat in winter, while the overwintering stage of single-brooded butterflies is sensitive to extreme heat in winter. It must be noted that single-brooded butterflies overwinter in all four life stages. (The overwintering stage depends on the species, but the larval stage is the most common overwintering stage.) In addition, extreme precipitation during the pupal stage drives negative population change in a number of single-brooded butterflies.

What about our multi-brooded species?

Extreme heat during overwintering and extreme precipitation during first- and second-generation adult life stages are the most frequently occurring extreme variables causing population declines in multivoltine species (67%, 58% and 50% of all multivoltine species affected, respectively). As in single-brooded species, adult and overwintering life stages have opposite population responses to temperature extremes. Extreme heat during the adult life stage (outside winter) is associated with positive population change in 42% of species.

Drought plays a much more important role in multi-brooded species than in single-brooded species. Drought negatively affects 50% of species during their second larval life stage, but has a positive impact on 25% of species during their first ovum life stage.

The study, carried out in the UK, found that multi-brooded butterflies are more sensitive to extreme climate events than single-brooded species, with all life stages, ovum, larvae, pupae, adult and overwintering represented in the nine most important variables in the combined model.

Extreme precipitation during the overwintering stage does not significantly negatively impact multi-brooded species or single-brooded species. This is very good news, because last winter was extremely wet and not extremely warm.

A striking feature of this summer’s butterfly story is the Ringlet population, which, where I look, is the largest I have seen for about 10 years. It had declined in my area of County Meath, with low numbers in what appear to be excellent habitats. Last year, I counted a mere 17 Ringlets on my South Meath transect. On June 25th, I counted 22 Ringlets there during a single visit. It is proving abundant in NE and NW Kildare.  The Meadow Brown, another single-brooded butterfly, is numerous too. Orange-tip, a spring flyer now finished its flight period, was numerous this spring.  Weather/climate is not the only influence on populations, but it is a key framework for species presence and population size.

Despite their sombre appearance, our Ringlet and Meadow Brown populations must not be overlooked, and counting them provides data on how our grasslands are performing and how weather and climate influence the habitats and populations.

We can also look forward to seeing our largest and most glamorous species in July. The first Silver-washed Fritillary of 2026 is due any day, and the first Dark Green Fritillary reported to our recording scheme this year appeared in Portrane, Dublin, on the 25th of June. We await our first Brimstone and Peacock, but the first brood of Commas has already made their appearance; these have so far been the golden form, which breeds immediately after emergence. Later in July, some dark-form Comma butterflies will appear. This form delays breeding until next spring.

The Small Tortoiseshell’s first brood is now flying. These are the children of those who passed the winter as adults and bred in spring. The new generation is behaving like the golden Comma, and is mating and laying eggs. These will produce a second generation that appears in August and September. However, a few Small Tortoiseshells will not breed and will enter an overwintering state, with dark form Commas. This flexibility allows Irish Commas and Small Tortoiseshells to capitalise on good conditions in warm, sunny summers with good rainfall while setting aside some individuals to delay breeding to safeguard against the onset of unsuitable conditions later in summer.

The highly unpredictable weather in Ireland can drive people to distraction. Last winter was dreadful for one’s mood, with miserably wet, dark weather for several weeks. However, our butterflies survived, and some are doing quite well this summer. Their colour gives us something to look forward to and enjoy, while their current abundance highlights their resilience in the face of meteorological adversity.  There’s some comfort in that for us!

But we must be on our guard. Extreme heat during winter is bad news for butterflies. Our climate is predicted to have hotter summers, which is good for butterflies, but warmer winters, which are detrimental. Will the benefits of warmer summers be outweighed by the negative winter effects?

Keep counting our butterflies…

Key Reference

McDermott Long, O. 2017, An investigation into the vulnerability of UK butterflies to extreme climatic events associated with increasing climate change, University of East Anglia.

All Photos copyright J. Harding.

The recent hot, sunny weather makes everything outside look brighter. Winged insects can move with ease, finding it easier to feed, seek mates, lay eggs or move through the landscape. In Britain, and presumably in Ireland, extreme heat is associated with better outcomes for most butterfly species.

In this post, we look at some native wildflowers that bloom in June.

The Bloody Crane’s-bill flowers from May and throughout June, with repeat flowering into the rest of the summer and early autumn. It is used by hoverflies, bees and butterflies, and is easy to grow, though it favours lime-rich, free-draining soils.

The Smooth Hawk’s-beard is common and often abundant on dry grasslands. It reaches up to 1m and has hairless stems and glossy, pinnate leaves. It is among the top 20 flowers in Ireland for supporting high pollinator diversity (see (e) below). It also ranks highly for (a), average abundance of visitors, (b), average species richness of visitors, (c), betweenness centrality (how connected it is in the plant-pollinator network) (d), duration of bloom, (e) and functional complementarity (supporting different insects).

Upright Hedge Parsley looks a little like Cow Parsley but comes into flower later and is a more delicate flower, and often has a pinkish tinge. It occurs beside hedges, often in dry places. It does not appear to be the foodplant for any of our butterflies or macro-moths, but it is a nectar source and is rather elegant. It has been recorded as a larval foodplant for the Southern Swallowtail butterfly, a southern European species.

This fragrant flower is used as a larval foodplant by some beautiful moths, such as Small Elephant Hawkmoth and Hummingbird Hawkmoth and several carpet moths. It likes dry grassland and has a beautifully evocative honey scent. The plant has several medicinal uses and was even used as an alternative to renin to coagulate milk in cheese production. It deserves a place in any wilding project, for its colour, fragrance and overall value for the grassland ecosystem.

This tall, multiflowering biennial or perennial flower is a considerable draw for nectar-feeding invertebrates. Painted Lady butterflies are especially keen on its flowers. This also needs dry situations and can grow in very shallow soil.  In warmer countries, it seems to attract much more attention from butterflies than it does in Ireland, with Six-spot Burnet moths drawn to it, sometimes in their hundreds!

This common flower can be white, pink, purplish, and it varies in height too. It is used for nectar by some butterflies, including the Silver-washed Fritillary and Marsh Fritillary. It occurs in dry grassland and will hybridise with Heath Spotted Orchid. It will appear in gardens that are not treated with fertilisers, and is a sign of undamaged soils. It is used as a foodplant by the Buff Ermine moth.

This tall plant is usually found in wet places, such as wet grassland, fens and river and canal banks. It is a rich source of nectar for many insects.

This fragrant wetland plant with its fragrant, frothy, creamy blooms epitomises summer. The flowers seem more important to bees, but butterflies will use them too. The leaves are eaten by Emperor Moth caterpillars, and by caterpillars of other macro-moths, such as Sweet Gale, Powdered Quaker and Hebrew Character.

Many plants that have finished flowering for the year are very important for pollinators, especially for their immature stages. The flowers of Blackthorn are eagerly used by spring flying moths and butterflies, but their leaves are food for larvae, notably by the Brown Hairstreak butterfly.  About 54 macro moths feed on the plant, including the Brindled Beauty.

The overall message is, go native! These are the plants that feed most of our insects. Many non-natives are poor for pollinators, and some are invasive and damage our environment. Go native!

Key Reference

Russo, L., Fitzpatrick, Ú., Larkin, M., Mullen, S., Power, E., Stanley, D., White, C., O’Rourke, A., &Stout, J. C. (2022). Conserving diversity in Irish plant–pollinator networks. Ecology and Evolution, 12, e9347. https://doi.org/10.1002/ece3.9347

Corfu is reputed to hold high biodiversity, including butterfly populations. Armed with advice from Ionian Butterfly Conservation and the Field Guide Corfu produced by the European Butterfly Monitoring Scheme, we decided to see this for ourselves. We were not disappointed.

Corfu sits in the Ionian Sea, just 2km from Albania and about 10km from the Greek mainland. It is about 593 square km in area, c.57km in length, and about 28km in width at its widest point. The north is especially well wooded, with about 36% of the island under tree cover, although much of it consists of Olive plantations, mostly hundreds of years old. The economy is mainly reliant on tourism, but olive oil production is also important. Central and southern Corfu are the main agricultural areas. The island has about 101,000 residents, most of whom speak English. Corfu town holds about 40% of the population. Corfu has a Mediterranean climate, with hot, dry summers and mild winters when most rainfall occurs. The island is remarkably green, a feature striking for those familiar with the Mediterranean region in summer.

We visited from June 2 to June 13, and daytime maximum temperatures were typically 25-27 Celsius, with night temperatures about four Celsius lower. We focused mostly on the northern areas, which we heard were rich in butterfly populations. We were not disappointed!

The best areas for butterflies were the open flower-rich edges and clearings in scrub, woodland, and olive groves, and along the tracks through these wooded areas. The soils are calcareous, and the clay soils, especially notable along the coast at Agios Georgios Pagon in NW Corfu, appear to retain moisture. In NE Corfu, near and around Mount Pantokrator, the terrain is rocky. It contains a mixture of bare and sparsely vegetated ground, native woodland, grassland and scrub known as Maquis, the term used to describe evergreen scrub in the Mediterranean basin. Common scrub species include Strawberry tree Arbutus unedo, Lentisk Pistacia lentiscus, Myrtle Myrtus communis, Holly Oak Quercus coccifera and buckthorns such as Mediterranean Buckthorn Rhamnus alaternus and Jerusalem Thorn/Christ’s Thorn Paliurus spina-christi.

Grassy areas along roadsides were also rich in butterflies. In some areas, the populations were so large that people gazed at the spectacle. This included areas in coastal villages, where Cleopatra butterflies mixed with Large and Small Whites, Painted Ladies and Southern White Admirals to feed on garden flowers, especially the non-native reddish-purple climbing plant Bougainvillaea.

The various trails through the landscape, especially the donkey trails, were very rich in butterflies. We walked part of the donkey path from Makrades village toward the coast. Limestone cliffs edge part of this walk, with interesting flora in the narrow strip between the cliff and path, excellent for butterflies. We found the umbelliferous plant Scaligeria napiformis, a foodplant for the extremely range-limited rare butterfly used as the symbol for Butterfly Conservation Corfu, the Southern Swallowtail Papilio alexanor, the only European butterfly that roosts with wings fully extended.

We found the caterpillars, black, white and orange, busy chewing on the seeds of the foodplant. When disturbed, it raises a fleshy, yellow organ from the first segment behind the head, producing a fluid that stinks of rotten pineapple. Presumably, this deters birds. Later in our stay, I found the caterpillars on Giant Fennel Ferula communis at sea level near the coast near Ipsos/Ypsos, NE Corfu. In Europe, it occurs only in small areas of SE France, NW Italy, W Croatia, parts of Greece, usually in mountains, Albania and the Republic of Macedonia, and its occurrence within these areas is local and sporadic.

Corfu has four papilionid (swallowtails, festoons and apollos) butterflies, three swallowtails and the Eastern Festoon. The swallowtails present are Common Swallowtail Papilio machaon, Southern Swallowtail Papilio alexanor and Scarce Swallowtail Iphiclides podalirius. In Greek mythology, Machaon and Podalirius were sons of Asclepius, while Alexanor was a son of Machaon. Given their legendary roles as Greek deities, these butterflies should occur in Greece. All are stunning, floating in warm breezes with insolent ease. They are swift in flight, often fluttering teasingly close only to vanish when the fancy takes them. All these large, showy butterflies usually feed by fluttering over their flowers, standing on them on tiptoes, their heft too great for most flowers to support them.

We caught glimpses of the Scarce and Common Swallowtails, but neither was numerous during our visit. Neither needs habitats of special character and can turn up anywhere, from exposed hill-tops to cosy gardens. The only chance of getting that good photograph is to find one early in the day, when they perch in warm, sunny places to heat their flight muscles for the day’s activities.

We found several species we have in Ireland, with the Brimstone (uncommon, but likely we were early in the flight period), Clouded Yellow, Wood White, Large and Small White (abundant, widespread), Small Copper (low numbers), Common Blue (abundant), Holly Blue (widespread but not numerous), Red Admiral (occasional), Painted Lady (widespread, numerous), Silver-washed Fritillary (widespread but not numerous), Speckled Wood (widespread but not numerous), Wall and Meadow Brown (widespread and abundant), Small Heath (in low numbers on short grassland), and Small Skipper (widespread but not numerous). The others we share with Corfu that we didn’t see, such as Comma and Peacock, might have been in the immature (non-adult) stage.

Overall, Corfu has 76 butterfly species; we saw 38, possibly 40 (Long-tailed Blue and Green-veined White might have been seen). We missed the spring flying species (April appears to be the key month).

It was wonderful to see ‘new’ species, like the Southern White Admiral, a graceful flyer that occurs in areas with trees, shrubs and hedges, including gardens. Males are notably smaller and patrol their habitats using regular flight paths and perch points. The smart deep black and starched white uppersides contrast with equally smart brick-red and white underwings. The most exciting finds were three grayling species, Delattin’s Grayling, which looks very like our Grayling, Great Banded Grayling and Eastern Rock Grayling, the latter two large and dramatic in flight, and equally happy in hot, dry woodland with clearings and open scrub and even hot, rocky places with low, scattered scrub.

The stunning Cleopatra butterfly/Mediterranean Brimstone was seen everywhere, from beaches to gardens, roadsides and rocky mountain slopes. Males are straightforward to identify; they have sulphur uppersides sporting a deep orange forewing flush. Females are much trickier. I saw many large females with whitish-yellowish uppersides (normal form), very similar to the female Brimstone with which it is easily confused. However, some females, especially in SE Europe, including Corfu, have pale yellow uppersides and even the deeper sulphur uppersides, like the male Brimstone. We saw all three colour forms, and it took me a couple of days to be sure about what I was looking at. The Cleopatras were absorbed in feeding up for ‘winter’. It hibernates from the end of August, reappearing in February, although it probably breaks hibernation to feed after August. It was obvious that the heat in more exposed areas, even during late morning, was quite extreme, as individual Cleopatras and Brimstones frequently entered bushes to seek the coolness of shade.

The butterfly that shocks the spirit is the Two-tailed Pasha. Large, showy and fearless, it is impossible to be unimpressed by this powerhouse. My first glimpse of the butterfly was obtained while driving to Agios Georgios in NW Corfu on our first morning, when a hot pursuit over the road was sighted. A head-turner, this swift butterfly would be impossible to approach if it so chose, but it is so fearless that it allows you to eyeball it. It looks weirdly shark-like in outline, and its dark eyes have an opaqueness that allows no insight. It returns human gaze with dark, unreflecting eyes, suddenly surging into the skies to attack an intruding male. Step away from his launch site, and this Exocet invariably returns to its post, bristling with aggression.

It breeds on the Strawberry Tree in open areas, and it likes maquis habitat on hillsides. Double-brooded, it is a tropical species restricted to the southern edges of Europe, usually near the sea. Seeing this species fulfilled the dream of a lifetime.

Another lovely butterfly we saw, and in great numbers, is the Balkan Marbled White (BMW). Despite being numerous (we saw around 200 in and near Old Perithia), it is geographically restricted, found only in SE Europe (also in Turkey, Transcaucasia and N Iran). The lovely black and off-white marbling patterning is classy and striking in an understated way. Like many butterflies, it was strongly attracted to scabious flowers, especially Sweet Scabious Scabiosa atropurpurea. Newly hatched BMWs are easy to observe and photograph. After a few hours, males become active, feeding and mate-seeking during sunshine, settling quickly in overcast weather. This response to cloudiness was noted in all the butterflies we observed.

Another interesting butterfly is the Lattice Brown. It is large, about the size of the Red Admiral, and quite skulking. It rarely appears in the open, fluttering in shady scrub, Bracken and trees, where males scour the branches, doing circuits of the tree limbs, presumably looking for love while females prospect for egg-sites (it lays on trees). It is extremely hard to approach, and the dull light of the woodland does nothing to conceal the human approach. This orange and brown phantom of the forest is agile and ghostly, a spirit that melts into the earthy tones of hot shade. It is confined, in Europe, to the SE.

Large, Small, Mallow and Lulworth Skippers were widespread, with the Lulworth Skipper particularly abundant. Another eye-catching butterfly is the Spotted Fritillary, especially the orange-red males. This is probably the commonest fritillary in Europe. We also spotted the Southern Comma; brighter and paler than the Comma, it likes basking on rock and breeds on Pellitory-of-the-wall.

Butterflies were found elsewhere, but special hotspots are Old Perithia, a beautiful 14th-century village in a breathtaking setting, the areas immediately inland of Agios Georgios, accessed by tracks through olive groves and the donkey path from Makrades. I am tempted to visit in April for the spring butterflies!

Looking at the abundance and at how widespread the Corfiot butterflies are, one worries more about the state of Ireland’s species. However, there are some concerns. Some olive growers use herbicides under the trees, eliminating important grasses and flowers for nature. This was unsightly and destructive, and no butterflies were observed in poisoned areas. Many olive groves were not poisoned, and these are great for insects. Like many residential areas in the Mediterranean region, garden flowers are grown instead of natives, but gardens are not extensive enough for this to be a major problem.

The scenery throughout the northern half of the island is simply spectacular. This might be true of the South, too. People are helpful and friendly, and the food is excellent with options everywhere in towns, villages and on seafronts. The roads are often narrow, and upland roads contain many sharp bends, so slow, cautious driving is essential. The island is green, despite the Mediterranean heat and dryness, quite different to nearby mainland Greece and Albania. No wonder Gerald Durrell called it ‘The garden of the gods.’

A special thanks to Chris from Ionian Butterfly Conservation for his help in identifying a couple of difficult species. Ionian Butterfly Conservation runs a recording scheme and would love to receive your records. You can learn more at https://ionianbutterflyconservation.org/index.php

All photographs copyright J. Harding