The latest Irish Butterfly Monitoring Scheme report 2023 (Judge and Lysaght 2023) mentions the six most common butterflies recorded using butterfly transect recording.
1. Meadow Brown 7716
2. Speckled Wood 5678
3. Ringlet 3849
4. Small Tortoiseshell 3582
5. Peacock 2997
6. Green-veined White 2488
While 2023 lacked warm, dry summer weather after the end of June, populations of some species proved quite high. I was thrilled to see a great recovery in Peacock numbers, for example, which were much lower in 2022. The Small Tortoiseshell also featured in thrilling numbers during 2023 in the places I look for butterflies, chiefly south Meath and north-west Kildare.
The figures given above are taken from transects, not from casual recording. Transects are fixed route walks when counts are made each week from 1 April to 30 September or are made five times during this period.
Casual butterfly recording is recording butterflies seen in a location but without necessarily visiting that location regularly and probably not applying a standardised counting methodology. This does not mean that casual recording is not valuable. Casual recording is vital to obtain distributional data meaning it allows us to know where in a country butterflies occur. Furthermore, many casual recorders report their sightings from an area they visit regularly, so results can be broadly similar to those obtained when walking the fixed route used in a transect.
The records on the Butterfly Conservation Ireland record database are a mixture of transect records, records from regularly visited locations and records arising from one-off site visits.
As an imperfect, interim comparison exercise, we compiled the records Butterfly Conservation Ireland received of these six most common species from the beginning of 2024 to the end of August 2024 and ranked them numerically.
Here is what we found.
1. Meadow Brown 2225
2. Ringlet 1632
3. Speckled Wood 642
4. Green-veined White 526
5. Peacock 245
6. Small Tortoiseshell 188
While the Meadow Brown held the top spot, the other five species changed their placings. The crashes in the Peacock and Small Tortoiseshell populations are particularly striking.
The number of Small Tortoiseshell recorded in July 2023 (351) and for the Peacock in August 2023 (881) heavily underline this collapse. August 2023 saw more 72% more Peacock records than the first eight months of 2024. For the Small Tortoiseshell that figure is 46%. A comparison for both species using the full years will show even steeper drops.
We hope to bring you that analysis in our Annual Report 2024. For the Annual Report 2023, see https://butterflyconservation.ie/wp/butterfly-conservation-ireland-annual-report-2023/
We expect the figures for the Small Tortoiseshell and Speckled Wood to increase appreciably during September, a key month for both but the damage to the Small Tortoiseshell from April to August is too severe for its abundance to come close to last year’s population.
Several consecutive months (July 2023-April 2024, except February 2024) with heavy rainfall is the likeliest cause of the declines. While June and July 2024 had below-average rainfall in most places in Ireland, the temperatures were below average everywhere in July and nearly everywhere in June. In August 2024, the temperature was below average in most areas and rainfall varied widely, with Dublin Airport receiving 50% of its average rainfall, compared with areas in the west of Ireland which saw their wettest August since 1992 (Belmullet) and 1985 (Newport).
Two weather stations had their wettest August on record. These were Malin Head, Co Donegal with 181.3 mm (record length 69 years) and Knock Airport, Co Mayo with 215.4 mm (record length 28 years). The puzzling month is May 2024. Met Eireann reported May 2024 as the warmest on record; however, it was dull and overcast much of the time, with all available monthly sunshine totals below their long-term average. Direct sunshine is important for butterfly and moth larvae. Perhaps this deficiency added to the crisis.
I have yet to see a Small Tortoiseshell in my garden in 2024; I have seen this butterfly in my garden for each of the last 26 years. I hope for a September bailout. We could do with a burst of butterfly joy!
Key References
Judge, M and Lysaght, L. (2024). The Irish Butterfly Monitoring Scheme Newsletter, Issue 16. National Biodiversity Data Centre.
Past weather statements (2024) Met Éireann – The Irish Meteorological Service. Available at: https://www.met.ie/climate/past-weather-statements (Accessed: 03 September 2024).
One of Europe’s most widespread blue butterflies (absent in Ireland), the Chalkhill Blue Lysandra coridon, a relatively large species of blue which in the male has bright pale ‘chalky’ blue uppersides has been studied for its relationship with ants, its conservation needs, especially in England and its genome. Genome refers to the full complement of DNA in a cell. DNA contains the information needed for an organism to develop. Humans have 23 pairs of chromosomes in the cell’s nucleus. As is the case for butterflies, half are inherited from each of the parents. The haploid number in a human sex cell is therefore 23; the full complement after the fusion or joining of the chromosomes, the diploid number, is 46.
The Chalkhill Blue, however, does not always conform to this neat formula. From Spain to Bulgaria, the chromosome numbers in Chalkhill Blues range from 87-92 with higher counts predominating in eastern Europe. From southern to northern Europe, the chromosomal range is 87-90. Why has the butterfly added chromosomes as it moved north after the last Ice Age, and while moving east? Was it adapting to a cooler climate? Typically, an animal contains a fixed number of chromosomes; a butterfly with more or fewer than another butterfly might be a different species.
Does this mean that the ‘Chalkhill Blue’ in England and northern Europe is a separate species from the Chalkhill Blue in Northern Spain? Not necessarily, according to Tom Tolman, author of the Collins Guide to The Butterflies of Britain and Europe, expertly illustrated by Richard Lewington.
Tolman states the change in chromosome numbers from Spain to Bulgaria appears clinal. A cline is a progressive, usually continuous change in one or more traits over a geographical or altitudinal range. An example of a cline in Ireland might be the change in the proportion of brown to blue female Common Blue butterflies. In drier coastal areas in eastern Ireland, most females have brown uppersides. As one moves west, there is a progressive change from brown to blue, with some females in the far west showing very little brown on their uppersides.
No one currently believes these blue and brown Common Blues are separate species. In Scotland, the Common Blue produces one generation a year and maintains this characteristic even when bred in the south of England. It is genetically programmed to produce only one generation but this genetic difference with its southern English cousins does not make it a separate species.
Neither are factors such as appearance always reliable species indicators; the Wood White and Cryptic Wood White are identical but separate species. The most accepted definition of a species is based on whether two individuals can or are willing to mate to produce offspring that are healthy and can reproduce.
This occurs when Chalkhill Blue butterflies with slightly different chromosome numbers pair. The additional unpaired chromosome is excluded. While this might result in the loss of some genetic information, such loss is likely selective and does not prevent the development of viable offspring. Nature finds a way.
There is plenty of confusion concerning the Chalkhill Blue. Many colour forms confuse taxonomists as to what butterfly they are looking at. Some believe that the butterfly that occurs in central Spain, Lysandra coridon caelestissima (Verity 1921 Type Locality: Central Spain, Albarracin) is a sub-species [i]of the Chalkhill Blue; others say it is a separate species. Tolman (2009) accepts the Macedonian Chalkhill Blue Lysandra phillippi as a separate species. Based on appearance, I find it impossible to separate this butterfly from the Chalkhill Blue in England. The Macedonian Chalkhill Blue uses the same larval foodplant, Horseshoe Vetch and is single-brooded, appearing in July and August, like populations in southern England. However, the Macedonian Chalkhill Blue has a much lower chromosome count, ranging from 20-26; in the Chalkhill Blue, this ranges from 84-92.
Just because the Chalkhill Blue has many more chromosomes than the Macedonian Chalkhill Blue does not mean that there are significant genetic differences. Some genes (DNA sequences on a chromosome) are redundant, persisting as a legacy of evolutionary history. In humans, the appendix is largely believed to be redundant, for example.
Some believe the Chalkhill Blue might be producing new species through fission events. Fission occurs when a single entity divides into two or more parts and the regeneration of those parts to separate entities resembling the original. The object experiencing fission is usually a cell, but the term may also refer to how organisms, bodies, populations, or species split into discrete parts.
A study published in February 2024, Comparative genomics reveals the dynamics of chromosome evolution in Lepidoptera, looked at butterfly genomes and found that most have shown remarkable stability, changing little over 250 million years. However, changes occurred in a few species, including the Chalkhill Blue. Most butterflies hold 28-31 chromosomes, not 90 plus as is often the case in the Chalkhill Blue.
To investigate the dynamics of fission in the Lysandra genus, the study reconstructed the events that gave rise to the genome structures of Chalkhill Blue and the closely related Adonis Blue Lysandra bellargus. Seven pairwise fusions generated a karyotype (full complement of chromosomes) of n = 24 in the last common ancestor of the family Lycaenidae (the coppers, hairstreaks and blues). Fifteen fissions then generated n = 39 in the last common ancestor of Lysandra. Subsequently, Lysandra bellargus underwent six fissions generating n = 45 and Lysandra coridon experienced at least one fission event in 37 of the 39 chromosomes of the Lysandra last common ancestor. An overwhelming majority of the 90 chromosomes in Lysandra coridon mapped to a single Merian element (Merian refers to ancestral linkage groups of modern butterflies and moths) and show conservation of gene order. The few Lysandra coridon chromosomes that contained segments from more than one Merian element derive from the seven fused chromosomes present in the common ancestor of the family Lycaenidae.
The study states that fusion and fission events are rare and very rare respectively and overwhelmingly occurred in just eight of the 32 ancestral linkage groups modern butterflies and moths are derived from. Other species that have undergone such changes are the Large White Pieris brassicae, Green-veined White Pieris napi, Small White Pieris rapae, Tinea semifulvella, Hewitson’s Tiger-wing Melinaea menophilus, Melinaea marsaeus, Black-veined White Aporia crataegi, Lesser Marbled Fritillary Brenthis ino, Winter Moth Operophtera brumata, Brown Scallop Philereme vetulata, Wood White Leptidea sinapis and Lilac Beauty Apeira syringaria.
Of these, the Large White, Green-veined White, Small White, Winter Moth, Brown Scallop, Wood White and Lilac Beauty occur in Ireland. Some believe the Green-veined White is in an active state of evolution while others maintain the variations in this butterfly are influenced by ecological factors. Ecological factors that influence the appearance of a species can include climatic influences such as sunshine and rainfall levels, cloudiness, temperature, and features such as elevation and habitat conditions such as the presence of exposed rock, etc.
However, adaptation to ecological conditions can give rise to new species.
Speciation (the process by which populations evolve to become distinct species) can occur in response to changing conditions, such as a changing climate. Mutations (alterations in the DNA) occur naturally in all populations. Better-adapted mutants thrive while less well-adapted individuals gradually, or suddenly, disappear. Less beneficial traits are bred out by natural selection. This underlines the importance of conserving genetic diversity within species, meaning conserving a species across various habitat types, landscapes and continents.
However, we have seen that most butterfly genomes have remained stable over the past 250 million years. This indicates that Lepidoptera are well designed containing within their genome sufficient resilience to adapt to changing conditions to continue their purpose.
We ought to marvel at this winning design. Butterflies have been on the planet far longer than us. The first modern genera [ii] came into existence during the Paleogene era, between 23-66 million years ago. The oldest known still-existing species is the Ancient Metalmark Voltinia danforthi, from Sonora, Mexico. This butterfly evolved as long as 40-50 million years ago. Homo sapiens emerged about 300,000 years ago (Smithsonian Magazine, 2021).
Our destruction of most of the planet’s natural vegetation is challenging 250 million years of Lepidoptera existence, the continuation of one of the most important animal groups on Earth. We need to adapt rather than reshape the environment to suit ourselves.
Key References
Handwerk, B. (2021). An Evolutionary Timeline of Homo Sapiens. Smithsonian Magazine. Available at: https://www.smithsonianmag.com/science-nature/essential-timeline-understanding-evolution-homo-sapiens-180976807/.
McKie, R. (2024) Startling genome discovery in butterfly project reveals impact of climate change in Europe, The Guardian. Available at: https://www.theguardian.com/environment/article/2024/aug/11/genome-discovery-butterfly-project-impact-climate-change-europe-moths?CMP=share_btn_url (Accessed: 19 August 2024).
Tolman, T. and Lewington, R. (2009) Collins Butterfly Guide. Harper Collins, London.
Wright, C. J., Stevens, L., Mackintosh, A., Lawniczak, M., & Blaxter, M. (2024). Comparative genomics reveals the dynamics of chromosome evolution in Lepidoptera. Nature Ecology & Evolution, 8(4), 777-790. https://doi.org/10.1038/s41559-024-02329-4
[i] A subspecies is a population occupying a distinct geographical region, separate from other populations of the same species and having constant and clearly different characters; the subspecies can breed with the populations regarded as the species if they meet.
[ii] A genus (plural genera) is the group above species but below family, e.g. species: Common Blue Polyommatus icarus, genus: Polyommatus, family: Lycaenidae)
How many times have you noticed the absence of butterflies, bees and other pollinators this summer? Months of dull, windy weather are being blamed. Butterfly Conservation UK, who run their Big Butterfly Count across the UK spanning the last two weeks in July and the first week in August, have reported the lowest butterfly count in the 14 years they ran the survey.
So, it is not an impression, it’s fact. Here is an interesting illustration juxtaposing two counts in one of Ireland’s best butterfly sites in 2023 and 2024.
Michael Gray (19/07/2023)
Essex Skipper 8, Cryptic Wood White 2, Large White 26, Small White 12, Green-veined White 12, Common Blue 6, Holly Blue 2, Red Admiral 76, Painted Lady 22 (magnetized to Wild Thyme), Small Tortoiseshell 8, Peacock 31, Comma 6, Silver-washed Fritillary 9, Dark Green Fritillary 2, Speckled Wood 5, Gatekeeper 39, Meadow Brown 20, Ringlet 20, Small Heath 9, Silver Y abundant seen during my exploration of the Raven Nature Reserve from 10.00 am to 6.00 pm, covering about half the open dunes, all the wood down to the southern point, T 113 262, Raven Nature Reserve, Co. Wexford. A mixture of sun and cloud, 50/50.
Michael Gray (16/07/2024)
Essex Skipper 2, Large White 3, Small White 5, Green-veined White 13, Common Blue 1, Silver-washed Fritillary 5, Speckled Wood 5, Hedge Brown/Gatekeeper 17, Meadow Brown 20, Ringlet 82, Small Heath 11, Six-spot Burnet 4, Silver Y 12, Cinnabar larvae several between 11 am and 5 pm at and near T 116 231, The Raven, Co. Wexford. The weather was warm with intermittent sunny spells.
On 19 July 2023, Michael counted 249 butterflies and 19 butterfly species.
On 16 July 2024, Michael recorded 164 butterflies and 11 butterfly species.
Standing in habitats awash with nectar-bearing blooms in the Burren, I needed to search for butterflies there in June, instead of being surrounded by them, as I have been in years past.
The Influence of Weather on Butterfly Abundance
This shortage is not always easily linked to weather-related events; we had high populations of some species last summer, despite the deluges of July and August 2023. Strong declines in a particular year are not disastrous; butterflies have a high reproductive rate allowing for rapid population recovery when conditions are favourable.
A good year, with warm, dry, sunny weather in important months for larval growth for several species, March, April and June following cold winter weather can yield great results. We had warmer temperatures than usual in March and April in the last two years, but June 2024 was cooler than usual with nearly all mean air temperatures below their long-term average.
The greatest difference between these months was in the weather in June. June 2023 was the warmest June on record, and had less rainfall than the average, allowing the caterpillars of species such as the Peacock, Small Tortoiseshell, Red Admiral and Comma to develop rapidly. Species that fly during June (and May 2023, also very dry) had the weather needed to feed and breed.
Is June the key month for these species? The caterpillars of most butterflies are present in June, varying in their development stage according to species. Is there a sensitive phase in larval development during June for some species? Did the extreme rainfall of July 2023 impact populations flying in 2024? During July 2023, rainfall amounts throughout Ireland were high above the long-term average, ranging from 133% to 300% above the long-term average. Extreme precipitation is the number of days above the 97.5 percentile for rainfall during the life cycle period for a particular species at that particular site. A UK study (McDermott Long et al. 2017) found that extreme precipitation is the most frequent cause of population decline in adult butterflies during the first and second-generation adult life stages.
The same study identified the pupal stage of single-brooded butterflies to be vulnerable to extreme precipitation. Extreme warmth during winter was found to be damaging to butterflies. Last winter (December 2023 and January and February 2024) are described by Met Eireann as “mild and wet overall”. The study also found that generalist butterflies (our common, widespread species) suffer more than specialist butterflies from extreme climate events (extreme precipitation, drought, extreme cold and heat).
The larva is the growth stage, and larvae are sensitive to weather conditions, often needing precise ecological conditions, including optimum temperature, insolation, surface geology, vegetation type and vegetation structure, and foodplant quality to develop. Adults of some species will move to find the resources needed for sustenance and reproduction and some species can survive long enough to use occasional good weather to breed and lay eggs. Larvae are much less likely or able to move to avoid bad conditions. However, if adult emergence and breeding are delayed by unsuitable weather, the foodplants may be in suboptimal condition. Declines in foodplant quality might be fatal to the successful development of the caterpillar or might result in less healthy adult butterflies. Observers are drawing attention to the number of dwarf butterflies this year.
Interestingly, most butterflies (31/35) are on the wing in June and July. The monthly average of daytime maximum temperatures, sunshine hours, rainfall and windiness are the most favourable during these months. Thirteen species fly in March and 15 in October. After early October the numbers flying collapses, as the conditions and resources needed to sustain adult activity deteriorate rapidly.
When summer weather is poor the four factors contributing to the favourability index are reduced. However, some woodland butterflies are probably better placed to cope with these downturns, given their more sheltered environs; in this suggestion, I am relying on the record of poor summers not reducing Silver-washed Fritillary populations found the following summer. However, in cold summers the Wood White will produce no second generation to speak of, with pupae from the spring flight overwintering until the following spring. This plasticity enables species to ‘wait’ until conditions are at their best before attempting to reproduce but plasticity is limited. The Wood White pupae must hatch the following spring but have around 10 weeks of spring and early summer (June) to select from.
Perhaps the Silver-washed Fritillary caterpillar enjoys a phenological advantage over other woodland butterflies; its caterpillar feeds from March to early June only. This makes it vulnerable only to poor weather during three months, unlike the Speckled Wood whose larva occurs in most of the year and Wood White which exists in the larval form in May/June and August/September.
A feature that has been noted this year is the appearance of dwarf butterflies. This has been observed in Speckled Wood, Holly Blue, Small Tortoiseshell and Peacock butterflies. This is likely the result of insufficient food for the larva. In short, the food available might have been in short supply, food was unsuitable, or both. Some species can still pupate and produce adults when the larva is insufficiently fed but there might be species less able or unable to do this.
Does poor weather per se explain the shortage of butterflies?
The answer to low figures might lie partly in poor weather in combination with the quality of the habitat and where the habitat is located. In a cold, windy summer, butterflies that use species-rich grassland in highly exposed coastal locations, upland slopes and open areas in the Burren will struggle. In these circumstances, butterflies congregate in the most sheltered areas, making them more vulnerable to predators. Most observers have favourite places to record butterflies, especially those doing transect walks. A population can collapse on one site but not nearby. This year, for example, the Marsh Fritillary was numerous in Lullybeg but numbers were far lower in adjoining Lullymore. Recorder bias and location bias can distort results.
Therefore, a wider scope is needed to assess population trends. That is why the records sent to Butterfly Conservation Ireland matter. We are receiving evidence from various locations around Ireland to show the population trend of most butterflies is down compared with previous years, especially in the summer months.
The Role of Predators
Another factor in low abundance might be predation levels. Butterflies have many natural enemies. Many are obvious: birds, frogs, dragonflies, spiders. However, a greater number of predators are obscure. Many parasitic wasp species destroy vast numbers of butterflies and in some years these predators reach a peak that collapses butterfly numbers. This phenomenon has been thoroughly studied in the common brassica-eating whites, the Marsh Fritillary and Holly Blue. In the latter two, the loss can be so high that populations disappear from some sites for years. In landscapes with well-connected suitable habitats, butterflies will return, and populations recover. We might be seeing the peaking of parasite populations for some butterflies dragging numbers down.
Weather is the likeliest cause of 2024 Declines
However, because all butterflies flying in summer appear to be in decline, it appears most likely that a common factor is driving declines. The likeliest is our weather. All months from July 2023 to April 2024 had above-average rainfall except January. As we have seen, extreme rainfall damages populations.
Longterm Declines 2008-2023
There is little doubt that populations have crashed spectacularly in 2024. Looking at the population data for our butterflies during the period 2008 and 2023 tells us that we are seeing sustained declines. The National Biodiversity Data Centre report for 2023 shows that common species that are widespread and well-monitored are in trouble. The Large White (-70%), Small White (-69%), Orange-tip (-65%) and Green-veined White (-82%) are in the ‘strong decline’ category with populations lower than the baseline year 2008.
The strong decline of -82% in the Green-veined White since 2008 is particularly disturbing for this is rated as among Ireland’s most widespread butterflies, recorded in over 86% of Ireland’s 10 km squares. It breeds in wet and humid grassland, vegetated damp ditches, hedgerow margins and marshes, along the banks of waterways, woodland glades and rides and wilder gardens. These habitats are common so one would expect the butterfly to thrive.
However, the Green-veined White is not flourishing in areas away from the direct influence of modern farming. Its distribution in Ireland is probably unchanged but its abundance has reduced. The reasons for the decline of the common white butterflies are unknown but what should create alarm is the fact that the Green-veined White, a widespread butterfly that has many larval foodplants and is not a habitat specialist is undergoing a severe thinning. In a sense, this is more concerning than a rare butterfly being in decline.
A Major Crisis?
Rare species can decline when their habitat, occupying small areas is shrinking or suffering neglect but that does not apply to the widespread Green-veined White or other common whites. We need to consider whether our entire countryside is being degraded. The failure of our landscape to support healthy populations of unfussy, common species must sound the sirens.
Time to worry.
Let us hope that butterfly lover Matthew Oates is correct in his statement, “Never underestimate a caterpillar.”
Key References
Judge, M and Lysaght, L. (2024). The Irish Butterfly Monitoring Scheme Newsletter, Issue 16. National Biodiversity Data Centre.
Long, O.M., Warren, R., Price, J., Brereton, T.M., Botham, M.S. & Franco, A.M.A. 2017, “Sensitivity of UK butterflies to local climatic extremes: which life stages are most at risk?”, The Journal of animal ecology, vol. 86, no. 1, pp. 108-116.
The prolonged dull weather has done little for our mood or our butterfly populations. Our mid-summer butterflies are conspicuously inconspicuous. We should be dazzled by Peacocks, Commas, Silver-washed Fritillaries and Brimstones. Instead, we are being served the occasional Green-veined White, and plenty, it must be said, of Meadow Browns. Ringlets are plentiful in their favoured damp grassy haunts where you become the diet of horseflies and midges. The places most of us, if we are sensible, stay away from, except for people like me.
Our more glamorous species cannot stay out of sight indefinitely. The immature stages last longer in cool weather than in warm conditions and longer development times mean emergence will occur later than in most seasons in recent years. For example, our warm June in 2023 saw the first report of the Silver-washed Fritillary on 21 June when it was seen at Lullymore, Kildare, by Pat Wyse. June 2024 was cold. We did not register the first report of this butterfly until Michael Gray saw five recently hatched examples at The Raven on 16 July. The woodland at The Raven in south-east Wexford is in one of our warmer, drier places where emergence is typically earlier.
Significantly, the first report of a Silver-washed Fritillary in Lullymore in 2024 was on 23 July. It began to fly in Lullymore 32 days later than in 2023. When they finally hatch, what challenges do they face in a damp, dull summer and how does the butterfly face them?
The Silver-washed Fritillary is, in my opinion, the perfect butterfly. It shows the classic butterfly outline and beautiful patterning. The male’s deep orange uppersides are marked with black spots, diamonds, bars and chevrons. The female is paler overall, and she lacks bar markings. Both sexes have moss-coloured hindwings with silver streaks and a marginal silver band. The forewing underside apex echoes the hindwing’s mossy hue while the rest of the underside is more muted orange than the upperside.
The male is especially glorious in bright sunshine when the orange ground colour gleams irresistibly in the clear light. The glow across the wings of a pristine male is breathtaking, a simple gleam of perfection, as sublime as it is ephemeral.
In cool, overcast but bright weather, the butterfly can be active. An air temperature of 16 Celsius in calm weather will allow it to fly but it will need to vibrate its flight muscles when feeding on bramble or thistle to retain the ability to take to the air. Males will seek females along the edges of woodland and after its beautiful courtship, the couple settle in a tree. Trees are important to the species. Butterflies will shelter in trees when the skies threaten rain and at night. On dull, windy days that is where they stay, wings closed tightly while clinging to the underside of a leaf, often quite high in the canopy.
The butterfly can live for around a month, long enough to wait for a warm day. It can mate and lay eggs in narrow time windows. The wet summer of 2009 left us wondering how many Silver-washed Fritillaries we’d see in the summer of 2010. We saw many that summer. The butterfly had demonstrated its ability to make maximum use of good weather windows.
The summer of 2007 was even worse. There was constant rain for days, with heavy flooding in many places including damp woods where the Silver-washed Fritillary breeds. Flooding certainly kills caterpillars. Marsh Fritillary larvae near bank-bursting water bodies drowned in July 2007. However, the caterpillar of the Silver-washed Fritillary is mostly immune from summer, autumn, winter and early spring flooding. Water inundation is avoided by laying eggs on trees, usually on the trunk, often four or more metres from the ground. The female avoids the danger of summer heat by laying on the north-facing side of the trunk. After two to three weeks, the egg hatches and the tiny caterpillar hibernates in a crevice in the bark, staying put until spring when it descends to the woodland floor to feed on violets.
There are few butterflies more graceful than the Silver-washed Fritillary. In hot sunshine, young males become extremely restless, darting to inspect flowering brambles for a resting female, or flying with rapidly beating wings along the edge of a wood or a track through the wood, pausing very briefly for bramble nectar. It also likes Common Knapweed, Creeping Thistle and occasionally Wild Carrot, Angelica, Common Cat’s-ear and Rough Hawkbit. One moment it scours the canopy of a mature oak, before swooping down to settle tremulously on a pink bramble blossom then dashing off to pursue another male. The butterfly will sometimes glide when it wants to inspect its surroundings.
At times the butterfly basks quietly, its bright orange wings spread on a frond of fresh green bracken. A quiet approach will give you the chance of a good view and a photograph, but this is a vigilant creature who often will not perch for long enough.
As glorious as the uppersides are, it was named for the silver flashes on the hindwing, by Moses Harris (1730-1787). It has always been richly appreciated by butterfly lovers and artists, and for good reason. In 1888 the renowned English author and artist Frederick William Frohawk was thrilled to observe that “the Silver-washed Fritillary were in hoards in every ride in the New Forest.” Its beauty, elegance and wonderful courtship flight continue to work their charm today. Dr Jeremy Thomas waxes lyrical in his book on Britain’s butterflies: “Only one of the 50 fritillaries of Europe exceeds this butterfly in size, and none is more beautiful or more magnificent.” The butterfly’s species name, Paphia, is associated with the Greek goddess Aphrodite, the goddess of love, desire, sexual pleasure, fertility, beauty, and grace.
These nouns are imaginatively applicable to this gorgeous creature of mid-summer woodland. There are woods where flowers disappear before the butterfly’s flight season has ended and this might explain why individuals have been found away from breeding habitats, such as in gardens and parks. Despite its aerial powers it rarely leaves its breeding wood, and sometimes remains in a small part of the wood when most of it is unsuitable for breeding.
You will only find it in woods containing open areas where light reaches the herb layer where violets occur in some abundance. It inhabits oak woods, hazel woods, ash and ivy woods and woods on peat containing willow and birch. It is happy in woods containing Scots Pine and non-native pines, as long as these are light-filled and contain enough nectar sources, usually bramble.
Now is the time to look for this lovely, powerful butterfly. It has survived in Ireland despite what we did to our woods over the past 500 years. Let us be grateful that we can still enjoy it.
Mid-summer has arrived but judging the summer season by butterfly abundance would be a mistake this year. Never have I experienced a summer butterfly famine like the one in July 2024.
Masses of flowering bramble and Creeping Thistle near my home in rural Meath typically hold fluttering confusions of butterflies in July but not this year. It is 19 July as I write, and I have seen three Commas, about six Small Tortoiseshells, and a similar number of Speckled Woods and Common Blues, no Red Admiral, no Painted Lady, no Peacock, one Brimstone since 1 July.
Butterfly Conservation UK, in the throes of its Big Butterfly Count, has found the Meadow Brown is showing the highest abundance at the end of week one. Butterfly Conservation UK recently stated: “So far this year we have seen a decrease in the number of butterflies seen across the UK. This is likely the result of a combination of a wet and windy spring and recent low temperatures.”
The weather causes they state applies in Ireland, and our experience of low population matches that in Britain.
The bleak picture has one exception, in Lullybeg Reserve at least. Hundreds of Ringlet butterflies are bobbing low over tussocks of moor-grass on Butterfly Conservation Ireland’s reserve. Individuals pause to bask and feed on Wild Valerian and Marsh Thistle, the latter plant a favourite for several mid-summer nectar and pollen feeders.
Last Tuesday I counted 259 Ringlets on just part of the reserve. It is a relief that at least one species likes cool, wet conditions! Indeed, Ringlets will even fly in dull weather and even in drizzle if it is muggy and warm. Although the butterfly is not brightly coloured, it is reassuring to see it in abundance, a sign that the grassland is in a healthy state for it. You can see a Ringlet at:
Despite the low abundance and reduced number of species flying in many areas this July, a few butterflies showed themselves at Lullybeg, and the flowers look wonderful.
We hope you like the photos that follow.
Finally, to close on a happy note, our reserve’s Marsh Fritillary population enjoyed another bumper year. In the Lullybeg area, the Marsh Fritillary’s recorded flight period was from 19 May to 3 July. Some were observed mating and egg-laying. A total of 204 Marsh Fritillaries were counted at Lullybeg in this period, a great number given the limited opportunities afforded by the weather to get out to monitor them.
Suffering from butterfly deprivation…empty grasslands… I’ve passed several (Buddleia) on my dog walks, but haven’t seen a single butterfly on any of them…A walk from Potter Heigham to Hickling Broad yesterday, limited butterfly activity…Ringlet seen on a transect walk at Foxley yesterday, very little else recorded apart from a few Speckled Woods…Weather has been unkind to us at our last 2 events the Wheatfen Swallowtail Day and Wild About Mannington. A Swallowtail put in a brief appearance at Wheatfen…
Here are a few comments harvested from social media reporting on butterfly populations in England during June 2024.
My experience in Ireland has been empty nettle beds, wingless skies, thin populations of some of our commonest butterflies and peering at the best habitats in Ireland to pick out a flicker of butterfly colour.
What’s wrong?
Let’s consider the weather. May 2024 was described as the warmest May on record by the Irish Meteorological Service. This surprised me. I wonder if night-time temperatures played a role in this finding. June, however, was described as cool, dry with the temperature below average nearly everywhere. All available sunshine totals were below their long-term average.
It remains cool in early July, with no upturn in temperatures predicted as I write on 5 July. Today we are looking at temperatures between 14 and 17 Celsius.
Is it just a case of below-par weather?
That’s unlikely.
It is certainly correct that our butterflies are strongly influenced by weather conditions with emergence greatly delayed by prolonged cool conditions. The sunny May and June saw the Silver-washed Fritillary begin to emerge on 21 June. We have not recorded it yet (as of 5 July). No new Brimstone has yet been recorded.
However, there appears to be an issue with our Vanessids: Small Tortoiseshell, Comma, Peacock, and Red Admiral. There are very few records of these butterflies this summer, in any life form. Between 16 May and 5 July, we have had four sightings of the Small Tortoiseshell, all singletons. Between 9 May and 5 July, two Commas were seen by Michael Gray on 3 July. We have not had any record of the Peacock since 31 May. Up to 5 July, only 20 Red Admirals have been reported to Butterfly Conservation Ireland’s recording scheme. These species breed on nettles and some parasitoids affect all four species. Has there been a peak in a parasitoid that has reduced populations? Has there been more than one factor impacting the butterflies? The waspPhobocampe confusa for example, parasitises Small Tortoiseshell, Peacock and Red Admiral and probably the Comma.
The cool conditions cannot delay the emergence of these species indefinitely. When they emerge, we might understand the nature of any impacts on their populations. All these species enjoyed abundance in 2023, especially the Small Tortoiseshell and Comma. Perhaps we are seeing a crash in 2024.
When cool conditions occur during a species flight period, such as during the Marsh Fritillary’s flight period in May and June this year, its flight period can extend later into June and into July, as it has in Lullybeg this year. In 2024 the Marsh Fritillary recorded flight period in Lullybeg has extended from 19 May to 3 July. In 2023, when we had a sunny May and June, the butterfly’s flight period was from 16 May to 22 June. In cool weather, the butterfly rests deep in vegetation waiting for suitable weather. Despite being typically short-lived, the adult Marsh Fritillary can sit out cool weather for two weeks, possibly longer, if needed.
Most of our butterflies are adapted to cool weather, but the adults thrive in warmer weather allowing them to feed, disperse, find mates and lay their eggs. Prolonged bad weather damages populations which rebound quickly in years with better weather.
Our Moth Morning hosted by Philip Strickland was a great success. We had over 100 species and still counting. The rain did not deter the moths, because the temperature was high enough to make them active.
There were several traps set in different parts of Philip’s grounds. Philip is wilding his four-acre site near Maynooth with very encouraging results. The grounds contain a native hedge over 100 metres long, with hawthorn, Common Hazel, Common Holly, Spindle, and Common Blackthorn, among other native plants. His grassland habitat contains native grasses, especially Sweet Vernal grass, and flora such as Common Sorrel, Cuckooflower, Common Knapweed, and buttercup species. This unspoilt grassland teems with Orange-tip and Green-veined White in spring followed by Meadow Brown and Ringlet while shadier spots are the Speckled Wood zones. Small Tortoiseshell and Red Admiral use his nettles and a closer look might reveal Comma too. Philip’s incipient native woodland which contains Pedunculate Oak of Irish provenance will become an enormous asset to biodiversity as it matures.
The grounds are managed in sympathy with nature. No chemicals are applied, and native plants are central to everything Philip is doing. The basic infrastructure of indigenous plants already in situ is being built upon by adding more and gradually removing non-native trees put there by the previous owners.
The results revealed by the moth count on Saturday 29 June underscore the importance of the native planting not only in the 109-plus species found but in the abundance of individuals and the range of habitats and breeding requirements represented. Tree-breeding species, grassland and scrubland breeders were present.
As I write, the micro-moths are still being identified which will push the total up. The colours, shapes and textures offered all of us great pleasure. Green, yellow, red, black, brown, white and various shades and combinations of these hues tantalised and delighted. It is reassuring in an epoch of mass extinction to witness high abundance. Hopeful too, for optimism is needed. Everything cannot be bleak. The simple measures Philip adopted afford vital resources to hard-pressed animals in an intensively farmed region but also pleasure and inspiration.
We viewed the moths under cover from the rain which made for comfort and greater attention. The bigger beasts on view included the Elephant Hawkmoth, Swallow-tailed Moth, Light Emerald, the Green, Light and Dark Arches and the Large Yellow Underwing. The medium-sized moths were in great abundance: Clouded Brindle, some quite fresh, Common Emerald, Common White Wave, the descriptively named Spectacle and Dark Spectacle, the sharply-dressed Cinnabar, elegantly gowned White Ermine and its less showy cousin, the Buff Ermine were all in attendance. The Straw Dot, a grassland breeder which hates nitrogen fertiliser, showed in high numbers. What a treat.
The excitement did not end there. Philip laid on a wonderful refreshment for us in his home. Conversation, frequently contentious and animated, flowed. Mothing is about people too!
On behalf of Butterfly Conservation Ireland, thank you Philip for allowing us to hold our event at your home. Thanks to everyone who made the morning so enjoyable. The experience was a real pleasure. Our only regret is that it was not much better supported.
All photos J. Harding except where stated otherwise.
On 24 November 2020, the cabinet approved €108 for Bord an Móna’s peatland restoration project. The scheme covers an area of approximately 33,000 hectares of Bord Na Móna peatlands previously harvested for peat extraction for electricity generation. The details can be seen here: https://www.gov.ie/en/publication/136a7-bord-na-mona-bog-rehabilitation-scheme/
Shortly after the Government announcement, Bord na Móna announced an end to all peat harvesting on its estate of c.80,000 hectares. The details can be seen here:
Some peatland rehabilitation schemes have been undertaken under the government-funded peatland re-wetting scheme. In many bogs, this involves re-wetting the remaining peat by blocking drains and bunding, which sometimes involves using peat to form a dam to hold water. The objective is that the rewet peat supports the development of sphagnum mosses which help to retain carbon in the peat and absorb carbon from the atmosphere. Thus, fully functioning peatlands retain and absorb carbon dioxide, a key global heating gas. Damaged peatlands emit carbon dioxide; these drained peatlands are sources of carbon dioxide pollution.
Alongside the climate action benefits of peatland restoration are biodiversity (protecting wildlife) and ecosystem services (like flood and pollution control). Many specialist plants and animals rely on peatlands. Some Lepidoptera that thrive on peatlands are the Marsh Fritillary, Large Heath and Green Hairstreak butterflies and the Emperor, Dark Tussock and Oak Eggar moths. Peatlands hold rare birds like Hen Harrier, Merlin, Red Grouse and Curlew. The extremely rare endemic fungus Entoloma jennyi was discovered in a bog near Oughterard in Galway. This bog (not owned by Bord na Móna) is still being destroyed, despite being part of a Special Area of Conservation.
Even on the state-owned Bord na Móna bogs, peat extraction continues. While Bord na Móna has ceased harvesting peat, it still extracts peat. Peat is drained and removed to build wind and solar farm infrastructure, so it is important not to feel comfortable using electricity generated by wind and solar. Where partly privately owned, Bord na Móna bogs are damaged by continuing drainage and cutting. One example is North Timahoe Bog in Kildare, where a fine remnant raised bog is being damaged by a private owner who continues to bulldoze and extract peat to burn. The irony is that Bord na Móna has plans to rewet the area in its ownership but this is being compromised by ongoing drainage and peat removal. You are not being told the full story by most of the media. You can see the photos of the damage done below.
Images of the beauty being obliterated follow.
The European Commission is taking Ireland to court over its failure to protect the bogs designated as Special Areas of Conservation (https://ec.europa.eu/commission/presscorner/detail/en/ip_24_1232). Ireland is failing to protect the bogs the country is committed to protect. This does not include undesignated sites in private ownership where peat cutting can continue. The benefits of re-wetting are potentially significant. A UN report (Global Peatlands Assessment: The State of the World’s Peatlands, 2022 ) states that drained peatlands represent only 3% of the EU’s agricultural land and rewetting them would avoid up to 25% of the EU’s greenhouse gas emissions from agriculture.
Yet peat cutting continues, often with political support. The excuses quoted include other countries doing it and people needing to stay warm over the winter. Bad behaviour should not be our example. Peat is not cut to stop people freezing to death in winter. It is machine-cut to make money.
Butterfly Conservation Ireland does not like to bring you bad news. But the truth must be told.
The cool, windy sunny conditions we have seen during early June continued during our Mornington walk. The dunes are home to wonderfully flower-rich grassland where Skylarks are conspicuous by sight and sound, contributing their tune to wind and wave song. Strolling here amid the glories of the dune grasses reminds me how bland Ireland’s general landscape has become, despoiled and impoverished by the ravages of modern agriculture. The extreme east of Meath contains the county’s best semi-natural grassland habitats but even here threats are extending: montbretia, sycamore and Sea Buckthorn are all biological menaces, their alien invasive presence intruding onto this slice of remnant richness.
The scents of the flora and wild grasses recall childhoods for today’s over 40s. Few younger adults and children have these biological or memory baselines, a factor that will influence future perceptions of what Ireland’s land ought to look like. That’s one reason why maintenance of the good remaining patches is vital. We need biodiverse areas as a benchmark for restoration schemes for biological resources and exemplars to support action.
After uprooting most of the montbretia in one patch adjoining the parking area, we set out to seek nature. Scarily few Small Blues were evident. Their breeding habitat is in excellent condition, so why were there so few? A clue might lie in the condition of those we did see, all perfect, newly hatched. Perhaps we are seeing just the beginning of its flight period in this area. Many Common Blues showed wear and tear indicative of some days on the wing.
Small Heaths were active, males fighting for control of the breeding ground. Two were fighting like two male Speckled Woods who believe a patch is their property, circling each other in tight circles of fury, with neither giving way. This is typical of the behaviour of male Small Heaths I have seen elsewhere. According to Thomas and Lewington (2014), larger-winged males tend to win, so smaller males are pushed away from favoured mating sites, diminishing their chances of mating success. The same source states that males are less likely to be territorial during hot weather when they favour search flights rather than settling on the ground to await females.
We saw no Cinnabar moths, again suggesting that it is yet to emerge in Mornington. We saw a beautiful Yellow Shell moth, its golden shell-marked wings appropriate for a coastal habitat. A Mother Shipton moth was also recorded. A couple of fast-moving Ruby Tiger moth caterpillars were spotted too, one on the soil, the other on ragwort. Both wriggled off at speed when disturbed.
Common Blues were not numerous but striking, typically the large examples found in Ireland. A single female was seen, with brown uppersides. Those in the west and parts of the midlands are blue or contain blue with brown scales on their upper surfaces. The colour differences might relate to climatic conditions, with bluer females associated with cooler, cloudier, damper situations away from the east coast.
It was a pleasant event, and the lovely newlyweds who attended were great company. We wish them every success in the years ahead.
June Bank Holiday weekend is synonymous with the beginning of the Irish summer, imminent holidays, strawberries and cream, and Bord Bia’s Bloom festival, featuring 2024 21 show gardens. Laura Douglas, Head of Bord Bia Bloom & Brand Partnerships penned the welcome in the Show Garden Guide, mentioning as key themes living in ‘greater harmony with nature,’ protecting ‘wildlife and the environment in our gardens’ and providing spaces that offer wellbeing benefits. Kerrie Gardiner, the event content manager, mentions biodiversity and protecting the local landscape.
To test the claims about gardens protecting biodiversity, I applied the Russo Test. This is my name for the 2022 study (Laura Russo is the corresponding author) that examined Irish plant-pollinator networks. The study, Conserving diversity in Irish plant-pollinator Networks discovered that 35 plants are of the greatest importance for pollinators.
The scientists collated data from six studies in Ireland where obligate (necessary) flower-visiting insects (specifically butterflies/moths, bees, and hoverflies) were observed/collected while foraging on flowers from May through August in 2009–2011 and 2017 and April through October in 2018. Transect surveys were made for this study.
What does the study reveal? The study analysed flower-visitor interactions between 239 flowering plant species and 148 insect visitor species in Ireland. The composition of the insect visitor species observed was: 54.7% hoverflies (Syrphidae), 30.7% bees (Anthophila), and 14.6% butterflies and moths (Lepidoptera). However, bees dominated in abundance on flowers (61% bee, 35% hoverfly, and 4% butterfly or moth visits), like in other published studies.
The thirty-five plant species in the Irish plant-pollinator network that rank in the top ten of the different measures (visitation rate (a), average abundance of visitors (weighted degree, (b)), average species richness of visitors (unweighted degree, (c)), betweenness centrality (d), duration of bloom, (e) and functional complementarity (supporting different insects) (f)) ranked from highest (top) to lowest (bottom) under (e) are:
I tested each of the 21 show gardens against this list.
What did I find at Bloom?
A mere nine of these 35 plants were represented in the 21 show gardens.
Those recorded and the number of gardens they appeared in were:
Red Clover (3), Creeping Buttercup (1), Common Bird’s-foot-trefoil (2), Common Daisy (2),
Ribwort Plantain (1), White Clover (2), Field Buttercup (4), Dandelion (1), Box (1-2).
This is pathetic. The cant about pollinators and acting for them and biodiversity generally is mostly unsupported by Bloom’s gardens. There were few bees on show and zero butterflies, despite the warm sunshine. The vacuity of this window dressing was reinforced by the literature being handed out showing important plants for pollinators. So, it’s not that nobody knows what’s needed.
One garden, entitled Rewild, styled itself as a space that incorporates traditional high-intensity management and moves towards a ‘wilder, more natural space’ to mark ‘the shift towards embracing biodiversity and creating a space where people live in harmony with nature.’ ‘Pollinator-friendly plants and habitat structures invite insects and birds into the garden.’ The garden was certainly attractive, but bug hotel aside, there wasn’t much for pollinators there. There appears to be an obsession in most of Bloom’s gardens with cultivars of Brook Thistle Cirsium rivulare. The unadulterated plant is native to damp areas in East France and Southern Germany. Don’t bother with it. Grow our lovely native wetland thistle, Meadow Thistle Cirsium dissectum instead. I have watched Orange-tip, Marsh Fritillary and Dark Green Fritillary enjoying its nectar, along with bumble bees.
Annoying and ironic was the In Perspective Garden by the European Commission. The booklet introduces its theme thus:
This European Commission garden articulates the values of the EU Green Deal which seeks to make Europe the first carbon-neutral continent by 2050.
This initiative includes protecting our biodiversity and ecosystems and one of its actions is the Biodiversity strategy for 2030. The strategy aims to put Europe’s biodiversity on a path to recovery by 2030 and contains specific actions and commitments. These include the EU Nature Restoration Law and enlarging protected areas. One of the targets of the EU biodiversity strategy for 2030 is to legally protect and effectively manage a minimum of 30% of EU land by 2030.
I saw scant evidence in the plants used of a thematic link between this garden and nature restoration or biodiversity protection. I saw two herbs and one grass species in this garden native to Ireland: Wild Valerian, Red Campion and Wood Brome. Without native plants, biodiversity stands little chance of survival, let alone recovery. Our native butterflies, moths, and invertebrates generally rely on native plants for their life cycles. The European Commission should know better.
Two gardens deserve a mention for biodiversity protection. The garden with the most native flowers was the Brigid 1500 Commemorative Garden. I counted six native trees, one native shrub and seven native flowers: Common Bird’s-foot-trefoil, Cowslip, Common Daisy, Red Clover, Ribwort Plantain, dandelion and Meadow Buttercup.
The other garden that had a meaningful link with biodiversity was Nourishing Dairy-From the Ground Up by Tunde Perry sponsored by the National Dairy Council. The text describing this garden lacks the pretentious verbiage typical of many ‘compositions.’ The text describes what is there, and the garden encompassed the stated elements: ‘grass meadow, multispecies sward and Irish native trees, shrubs and hedgerows.’ This sward held Meadow Buttercup, Red Clover, Ox-eye Daisy, Yellow Rattle, Cowslips, Ragged Robin and Foxgloves. The shrubs included Common Hazel. This is the only garden where I saw a Lepidopteran, a Grass Rivulet moth laying eggs on Yellow Rattle, on the capsule holding the seeds.
Supporting Sick Children
One garden, Children’s Heath Foundation Garden of Music and Play designed by Declan McKenna listed the 31 plants used in the garden. It contains zero native plants and only one that is outstanding for butterflies, Verbena bonariensis. Providing a welcoming space for children in the new Children’s Hospital’s four acres of green space and 14 gardens and internal courtyards, mentioned in the leaflet provided, would benefit tremendously from native plants. Water Mint Mentha aquatica, Corn Mint Mentha arvensis, Wild Thyme Thymus polytrichus, Common Marjoram Origanum vulgare and Bog Myrtle Myrica gale (all native) have attractive aromatic leaves and blooms, providing children with visual, tactile, olfactory experiences as well as drawing in masses of pollinators. Add showy natives Common Knapweed Centurea nigra, Greater Knapweed Centaurea scabiosa, Devil’s-bit Scabious Succisa pratensis, Wild Teasel Dipsacus fullonum for structure, colour and clouds of hoverflies, bees, butterflies and moths and the benefits for children’s wellbeing, and their families, are hugely enhanced. Set a moth trap in the National Children’s Hospital native gardens twice a week from March to October for more well-being. Children and parents can take photos of the colourful butterflies visiting the plants. Plant some brassicas to attract Large White and Small White butterflies to breed in the hospital gardens, to show butterfly life cycles in action. Children could save seeds from some of the flowering plants to grow in pots at home, giving them more to look forward to. More imagination applied by the Children’s Health Foundation would greatly assist in the therapeutic journey travelled by children and their stressed parents.
Bloom is visited by tens of thousands of well-meaning gardeners every year. Another chance to evangelise about biodiversity, to demonstrate biodiversity. ‘Yet to meet expectations’ is a benign way of saying Bloom overall didn’t achieve the description stated in the Guide. The plants on show, overwhelmingly non-native, simply deceive people about the ecological relationship between plants and animals. Go native.
Photos J. Harding
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