Butterfly Conservation Ireland

A key challenge involved in organising outdoor events in Ireland is the weather. It is often said that in Ireland we don’t have a climate, we have weather. If it rains, you cannot hold a biodiversity event looking for moths and butterflies outside. You cannot have a butterfly walk without butterflies unless one can conjure them into being for the nature lovers attending the walks. The weather forecast for Saturday did not inspire confidence, only apprehension. A great suspicion arises when you see wall-to-wall sunshine and clear blue skies in Ireland at 7 am. It is typically a cruel trick to lull you into optimism.

By 9 am it had clouded over and at 9:30 am my windscreen showed a spray of rain. Amazingly, it got better after that. When I arrived at our meeting point, four people were already there and another 11 appeared before 10 am, so my confidence in the weather obliging us increased. We even saw sunshine, occasionally, and that was enough to bring butterflies, moths and the region’s legion of dragonflies into the air.

It is reassuring to see the expected species. Our outing was treated to plenty of Marsh Fritillaries, in Lullybeg, none in Lullymore. The butterfly appears to have vacated Lullymore West, although we did find a single pupa.* Before alarm bells ring, the Marsh Fritillary is famous for moving around a landscape, with colonies thriving in one area for some time and then moving elsewhere within a region. The habitat in Lullymore West remains suitable, but some attention is needed to prevent the increase in rank grass becoming a major survival challenge. That underlines the need for landscape-scale protection and management for the Marsh Fritillary.

Our walk had the benefit of sharp-eyed children, who, having keener eyes closer to the ground, are better adapted to spot insect life! That’s my excuse anyway!

Meeting children aged four to eight who know far more about nature than I did then is inspiring and reassuring; there is hope for the future. The energy the children brought to our event and their wonder helped make the hard graft of conservation work worth the effort. One child opined that the underside of the Marsh Fritillary is nicer than the upperside. She was excellent at catching the butterfly and gingerly holding it by the thorax, which avoids hurting the butterfly. At her age, many are the poor butterfly seized by whichever body part my greedy fingers grasped!

One child required caterpillars. I was glad the Brimstone larvae were available on the two buckthorn species in Lullybeg. These were all very small, smaller than they were this time last year.

Frogs were common enough to add excitement. We also encountered a couple of Song Thrush anvils, hard ground or branches on which snail shells were broken to obtain their succulent contents. We netted Four-spotted Chaser and Hairy Dragonflies. I was bitten by both species, understandably. No dragonfly wants to be handled by a human.  Plenty of blue damselflies glided about, glowing in the bright light. One of them fell victim to a Four-spotted Chaser.

Dingy Skipper, Cryptic Wood White, Green-veined White, Orange-tip, Small Copper, Common Blue, Holly Blue, Marsh Fritillary and Speckled Wood were ticked off, while Narrow-bordered Bee Hawkmoth (surely designed to impress anyone who sees it), Burnet Companion, Angle Shades and Silver Y were among the moths registered. We did not manage a Small Purple-barred moth, but it was probably not sunny for long enough to coax it to fly.

Overall, it was a wonderful day out. Our three German visitors enjoyed the event, and it is always great to have a chance to showcase the best of what Ireland’s biodiverse landscapes have to offer to our overseas visitors and natives alike. Biodiversity continues to boom in the Ballydermot region. Long may it be so.

*Since this post was published, we have been informed by the Irish Peatlands Conservation Council, which owns and carefully manages the reserve in Lullymore West, that the Marsh Fritillary has been recorded on the reserve in the past two weeks while carrying out their transect walks for the Irish Butterfly Monitoring Scheme.

Updated on 29 May 2024

 

When selecting sites for spring butterfly walks in the Burren one is not necessarily spoiled for choice, despite the presence of the highest quality habitats across the region. Large areas of the Burren are designated as Special Areas of Conservation, especially for orchid-rich grassland (known as Semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco-Brometalia) (important orchid sites) [6210]). This habitat is excellent for butterflies when well-managed, sheltered and south-facing. However, much of the area is exposed to the wind and contains insufficient scrub to provide the habitat conditions needed by spring butterflies and moths.

During the summer the more exposed grasslands are rich in grassland butterfly species, but spring butterflies need shelter. The east Burren is better for spring butterflies than the west, where there is less shelter. The sites we visited as part of the Burrenbeo/Butterfly Conservation Ireland Burren in Bloom Festival events, Fahee North near Carran Turlough and Clooncoose Valley west of the Burren National Park tick the required boxes.

Saturday promised us sunshine and light breezes. It gave us a grey sky and a light but chilling wind. This failed to cast a pall over our outing, well supported by enthusiastic lovers of the Burren. Moths trapped the night before were shown. The selection of spring moths was appreciated, especially the impressive Poplar Hawkmoth that loyally perched on one of the ladies where he remained for the entire walk.

We walked through the open scrub on limestone immediately south of the holy well, searching carefully for signs of Lepidoptera life. The ecological needs of the Pearl-bordered Fritillary were described; its larva needs direct sunlight and shading scrub, abundant lush violets growing in dry conditions that contain fresh tender growth, dry leaf litter among the violets and nectar sources for the adult butterfly. This is a high-maintenance butterfly. Only the Burren meets its needs.

We enjoyed the Burren plants which included super fragrant Burnet Rose, deep yellow Common Bird’s-foot-trefoil and aptly named Early Purple Orchids. Toward the end of the walk, we managed to spot a couple of Dingy Skippers (the Burren holds a pale, limestone-adapted subspecies of this butterfly) and Burnet Companion moths and finally, a lovely male Pearl-bordered Fritillary, netted and placed in a jar for all to admire his underside pearls and lovely deep orange uppersides decorated with a range of black markings. Just as we exited the site a Wood White was spotted, a lovely female showing her greenish hindwing underside, a feature of Irish Wood Whites; in Britain and Europe, the green is replaced with grey.

The group was so kind and appreciative it is a pity the weather did not allow us to see more, but Sunday delivered.

Sunday 19 May was sunny and warm with little wind. This event was also very well attended. We began by showing moths trapped the night before at Parknabinnia, near the roadside wedge tomb. This allowed us to see strictly nocturnal species. A Shears moth Hada plebeja was shown; this was a very well-marked example clearly illustrating the shear marking on the forewing. Muslin moths Diaphora mendica and White Ermines Spilosoma lubricipeda were shown. The Irish male Muslin moth is cream with scattered black spots while in Britain the males are grey or brown, and do not look like the same species. Other species were shown too, including a ‘May Bug’, the Common Cockchafer, a large, impressive beetle that is attracted to light. They are known in Britain as doodlebugs and because of their buzzing flight, they gave their name to the V1 rockets from the Second World War.

Clooncoose Valley is impressive, giving wonderful views of the landscape to the south, with cliffs, rugged hills, plains and wetlands, with limestone grassland, scrub, woodland, and bare limestone pavement encountered from the Green Road that makes the vistas accessible to walkers. This Green Road is bounded by classic Burren dry stone walls and in places by hazel scrub, sheltering this wildlife corridor from the wind.

Butterflies, moths, dragonflies and other creatures use the Green Road to move through the landscape, to seek mates, food and shelter. The Green Road contains good feeding resources and breeding habitats in places, so butterflies linger here. We didn’t have long to wait before meeting Pearl-bordered Fritillary, Wood White and Dingy Skipper butterflies and several Hairy Dragonflies. These were netted, jarred and passed around so everyone got to see these lovely animals. Later, a Speckled Yellow moth, a beautiful day-flyer was caught and passed for admiration. A Small Heath butterfly was netted. He was freshly emerged, showing rich chestnut uppersides.

Our turning point was the cottage (the only building in the area) adjoining the marsh where Large White, Green-veined Whites, Orange-tips and damselflies were spotted. We also saw a freshly hatched Common Blue gleaming iridescently in the glorious sunshine. Indeed, it was a day of brightness, happiness, beauty and sunshine, and I hope that everyone went home happy. I know I did.

Thanks to everyone who attended and made the day special. Sharing beauty and observation enhances the aesthetic experience and the appreciation of the wonders of the Burren. Thanks to Burrenbeo which joined Butterfly Conservation Ireland to organise the weekend’s events.

 

 

The misery of our weather since late June 2023 has sharpened our desire for better. We are struggling to see a large number of any butterfly except for the Holly Blue, the only Irish butterfly that is showing abundance this spring. This stunning little butterfly is currently occupying the streets in Dublin City, so impressive is its upward trajectory.

Warmth is the Holly Blue’s friend. City centres offer this heat and the amount of holly and ivy in warm urban settings is ideal for the butterfly. Add secondary foodplants like dogwood and escallonia to the menu and the Holly Blue is happy.

Most of our butterflies need wilder places. There is nowhere better in the midlands east of the Shannon than the bogs in northwest Kildare and east Offaly, known as the Ballydermot Bog group (includes Lodge Bog, Lullymore,  Lullybeg and other bogs), an area Butterfly Conservation Ireland and other organisations propose as a national park. And a stroll in good weather tells you why.

The complex habitat conditions provide a home for a vast range of animals. The area contains dry and very wet conditions, acid, neutral and alkaline soils, climax woodland, scrub, open grassland, bog, pools, lakes, rivers, swamps, reed beds, fens, and eskers often in intimate proximity.

The diverse landscape produces enormous biodiversity. But it is not just the range of life that impresses. The mass abundance is often breathtaking. At the right time of year, the profusion of flying insects in the air can be confusing but the copiousness creates excitement. Systematic counting becomes impossible. Estimates are essential. It can be impossible to separate species when species that appear similar in flight are met in massive amounts. It is impossible to separate the dancer and the dance.

That last Yeatsian statement is especially germane regarding animal life. The massive abundance is inseparable from the landscape of scale that maintains it. Such bounty must be nurtured and defended because it is rare in today’s Ireland.  Scarcity highlights abundance. Blandness emphasises ebullience. The Ballydermot Bog Group’s biodiversity underscores the bleakness and emptiness of the general landscape. Polluted, over-farmed, modified and gardened to its fingernails, modern Ireland offers so little compared with contemporary remnants that are redolent of past glories.

Restoration can be great but preservation is much greater. Better to retain our best rather than fix what is broken. Some broken things are irreparable.

Sauntering through Lullymore and Lullybeg on 15 May, in sunny weather punctuated by occasional overcast conditions was a slice of perfection. Nature must be encountered using every sense. We overuse our eyes. Touch, taste, smell and hearing should be commandeered to apply the multi-sensory approach.

The Hairy Dragonfly, superb on the wing and beautiful when seen close up, demands we use our hearing, touch and sight to understand its characteristics.

This is the earliest of our larger dragonflies to emerge and is thriving in many areas. It is better distributed and more abundant in Ireland than in Britain. It looks magnificent in flight, zooming purposefully in linear flight, looking like an Exocet missile locking onto a target. When the weather cools, it settles but on being approached, rattles its wings loudly and perhaps disconcertingly to a predator. When it has transferred sufficient heat to its flight muscles, it vanishes.

The Hairy Dragonfly packs a punch or rather a bite. Catch one and you will soon be bitten. While this is quite a shock and uncomfortable rather than painful to a human, its jaws slice through its prey. In one location in Lullymore, this dragonfly killed five Brimstone butterflies in a few minutes, catching them in the air and slicing their heads off. Decapitation is a clinical and effective way to dispatch a large butterfly. This quarry is then brought to a tree for dining.

The Hairy Dragonfly is joined en masse by the Four-spotted Chaser, a smaller but more robust-looking dragonfly. This dragonfly takes two years to develop and although it flies every year it is far more numerous in some years. At Lullybeg there are years when there are swarms of this insect. It becomes so numerous that male territories collapse. It flies from April to August and must be a great source of food for birds.

Attune your vision to miniature neon lights and you will pick out the blue damselflies: Azure, Common Blue, Variable and Blue-tailed Damselflies. They were marked present yesterday, gleaming around low shrubs and tall grasses, evoking a blue light district. There were hundreds; I didn’t try to count.

And so to the Lepidoptera. The area is one of only three Important Butterfly Areas (IBAs) in Ireland. The other two are the Burren and the headquarters of the River Suck.

Yesterday (15 May) it was the moths that dominated numerically. Silver Y is a resident and migrant moth, and it was everywhere, darting in and out of grass clumps, like a cyclist weaving around stationary cars on a busy highway. Despite the conspicuous buzzing flight it vanishes on landing, blending with rather than burying itself in the bleached tussocks of last year’s grass growth.

The Silver Y moths I saw were pale grey, indicating overseas origin. The paler form, seen here, typically originates in a hot climate. We could be looking at an African moth here.

Another moth that is both a resident and migrant, Angle Shades, was also buzzing around Ballydermot on 15 May. This moth is mainly nocturnal but can be seen in daylight resting on vegetation. Like the Silver Y, it breeds on a wide range of plants including Common Nettle and birches. There is plenty of food for it in the area.

By contrast, the Silver Hook is a localised, resident moth. This beautifully marked moth occurs in fens, marshes and boggy heathland so it finds good ground in Ballydermot. It is mainly nocturnal but flies by day when disturbed. It breeds on grasses and sedges.

An intriguing day-flying moth is the bee mimic, the Narrow-bordered Bee Hawkmoth. Another resident, this occurs only locally in wet grassland, on dry calcareous grassland and boggy places containing its breeding plant, Devil’s-bit Scabious. This buzzes like a bee, flies like a bee, feeds like a bee, looks like a bee… but has no sting. It is a moth, and the adult loves louseworts and milkworts.

Butterflies that are locally distributed in Ireland have a stronghold here. The Brimstone, which is absent from most of Ireland (absent from 80%) is common and often abundant in the Ballydermot region. I saw 14 Brimstones on 15 May, looking daffodil yellow (male) and pale greenish-white (female) in the pure spring sunlight. After spending nine months in hibernation, they do not look their best but still flung their brightness on the still brightening habitat.

Another local butterfly, absent from 84% of Ireland’s 10 km squares is the Dingy Skipper. Small and unglamorous, it has a cultish charm for butterfly lovers, looking like a childhood teddy bear recovered from an attic years later. It has a cuddly appearance, and needs care, being found only in small patches of suitable habitat in most of its recorded distribution. While it breeds on a widespread foodplant, its habitat requirements are quite precise, and it is common in Ireland only in the Burren.

To complete this post, I am showing you the Cryptic Wood White butterfly. It looks delicate and fragile on the wing, flying with what looks like a tremendous effort but it can stay airborne for prolonged periods, flapping along wood and scrub edges. Absent from Britain, its discovery, using genetic analysis, was announced in 2011. Until then it was believed to be a different species, the Wood White, a butterfly confined in Ireland mainly to the Burren and a few outlying limestone areas in south Clare and Galway.

This dainty creature is quite widespread in Ireland but breeds only in wilder places. Long live the wild and wilderness!

 

 

 

 

And I have felt
A presence that disturbs me with the joy
Of elevated thoughts; a sense sublime
Of something far more deeply interfused,
Whose dwelling is the light of setting suns,
And the round ocean and the living air,
And the blue sky, and in the mind of man:
A motion and a spirit, that impels
All thinking things, all objects of all thought,
And rolls through all things.

Extract from “Tintern Abbey” by William Wordsworth (1798)
Lines Composed a Few Miles above Tintern Abbey, On Revisiting
the Banks of the Wye during a Tour. July 13, 1798

Nature inspires everyone at some time in our lives. Perhaps it is the dawn chorus, the increasing day length in a dark, dank January, the first snowdrop, the first Swallow, the first Orange-tip butterfly seen after a long, wet winter.  This spring butterfly inspired Butterfly Conservation Ireland member Felicity Laws to craft the following verse. Based in West Cork, Felicity watches the changing seasons bring nature’s beauty to focus. Joy is often elevated by long absence, a sensation Felicity captures in her verse.

Enjoy.

CRAVING
A creeping, insidious longing
As the sun rises higher each day
Every brightening moment might reveal
A butterfly/damselfly/dragonfly
In all its shimmering glory.
Frissons of fear and love
Bubbling like quality champagne
As I try to extend the moment
A flutter catches my eye:
Will there be an identifying view?
Smooth slide for a photograph?
Will it bask? will it dematerialise
As if it had never been?
Whichever way it goes
The craving is slightly assuaged
Enough that ‘it’ exists
Whether or not I know
What ‘it’ is; fear dispatched,
Only love remains.
At the next exciting air tremble
Another opportunity or ten
Never too many!
And so on, a summer addiction,
Winter rehab flown with the first
Chitinous flicker of unfeathered wings
Magical natural beauty.

Felicity Laws, April 2024

Photos copyright J. Harding

Poem copyright Felicity Laws

Spring is here!

20 April 2024 gave us the first good weather day this spring. The forecast is for the sunny weather to extend into the middle of next week at least.  Several Small Tortoiseshells that entered my house to overwinter only for the central heating to disrupt their sleep, a late Peacock I caught in my garden and a late Comma from a nearby lane were overwintered in two sealed plastic containers. How many survived? There were around 20 butterflies. All but five survived, presumably higher than would in the wild.

See the release here:

If you have kept any butterfly or moth indoors, now is the time to let it go. Please check sheds, outbuildings and unused rooms for trapped butterflies.

 

On 1 April 2024 on a sunbaked hillside east of Qala village in Gozo, I enjoyed Swallowtails, Red Admirals, Painted Ladies, Clouded Yellows, Long-tailed Blues and Wall Browns. The temperature exceeded 31 Celsius that afternoon, the highest ever recorded in Malta during April. The airborne Swallowtail is eye-catching, blending silk with steel as it manoeuvres intense hilltop gusts. On ethereal high ground, this elusive butterfly evanesces beyond and within view, the ubiquitous cream Coraline limestone absorbing it only for it to condense to a just perceptible presence on a buff senescent sprig, typically African Carline Thistle, a relic of last summer’s moisture-starved ground. The Swallowtail’s command of the air in these windswept hills is soul-gripping, its beauty refreshing in the harshness of heat and naked rock.

Malta in spring sees no shivering in the rain and dank wind or peering at a murky sky for a hint of direct sunlight, a staple for early spring butterflies in Ireland. Ireland’s butterflies did not get much encouragement from the March and early April weather. Wet spring weather inhibits butterflies. March was wet so its above-average temperatures were unavailing. April 2024 shows no signs of being suitable but three weeks lie ahead.

I noted some positives this year. In his impressive book on British and Irish butterflies, Peter Eeles states that the Speckled Wood caterpillar can overwinter only in the third instar (instars are inter-moult stages in the caterpillar) with other instars dying with the onset of extreme cold. However, the fourth instar caterpillars I reared outdoors in County Meath survived the prolonged low temperatures during January 2024. Our Speckled Woods are tailor-made for the Irish winter.

Regarding winter survival strategies our butterflies occupy three categories: the species that migrate south, species that overwinter as adult butterflies and those that pass the colder months in juvenile stages (egg, caterpillar, chrysalis). Four hibernate as adults: Brimstone, Small Tortoiseshell, Peacock and Comma, and these have been seen this spring. They return to rest when spring weather reverts to winter. These species are long-lived as adults and can play a longer game.

For the rest of our resident butterflies, carpe diem applies. Ireland’s spring butterflies are particularly adept at exploiting brief good weather to transact their life’s work. On 3 April Lisa Scarff saw her first butterflies of the year on the Sheep’s Head peninsula in West Cork: a Holly Blue and three Green Hairstreaks. Green-veined whites were reported on 31 March (Lullymore, Kildare) and 5 April (Marlay Park, Dublin). A Large White was seen on 31 March (Sutton, Dublin). The increasing day length added to milder temperatures tempted these out of their pupae. These emerge over several weeks, spreading the risk, so that some will appear at the right time.

Another early spring butterfly, the Speckled Wood (unique in its ability to overwinter as a pupa or larva), is awaited. In 2023, the first Speckled Wood reported to Butterfly Conservation Ireland appeared on 30 March. Most of our spring butterflies are yet to emerge: Dingy Skipper, Cryptic Wood White, Small White, Orange-tip, Small Copper, and Wall Brown. As connoisseurs of butterfly beauty, you will be impatient to savour these delights. Of some delights, the delay makes the taste sweeter. Enjoy your butterfly recording in 2024: the weather will turn!

Records can be emailed to us at: conservation.butterfly@gmail.com

The information needed for a valid record is described at

Records

Our 2024 records are here:

2024

Jesmond’s book, The Irish Butterfly Book, is available in bookshops and by email jesmondmharding@gmail.com

 

When I was eight, my father bought me a book, A colour guide to familiar Butterflies, Caterpillars and Chrysalides by Josef Moucha, beautifully illustrated by Bohumil Vančura. There was not much money in our home, so I was surprised as well as delighted with the book. Many happy hours were passed drawing and painting butterflies from the book. The first butterfly illustrated is the Swallowtail Papilio machaon. The illustrations show the butterfly with wings extended, the pupa affixed to a dead stem and the feeding caterpillar, perched high on a foodplant. The plant is an unnamed umbellifer (celery, carrot and parsley family).

The Swallowtail is a large, beautiful species, well distributed in Europe. It also occurs in North Africa, temperate areas of Asia and parts of North America. It also occurs on Mediterranean islands, including small islands like Gozo (Malta). Last year, the Swallowtail on Lampedusa Island in the Mediterranean was identified as a new subspecies, not of the Common Swallowtail Papilio machaon but of the Desert Swallowtail Papilio saharae.  The adult Desert Swallowtail looks identical to the Common Swallowtail when seen in the field. The study that makes this claim examines all life stages and is a morphometric study (looking at the size, shape, colour etc of individuals). It did not use genetic techniques.

I have read the study carefully, and while the butterflies on Lampedusa have characteristics referable to the Desert Swallowtail, they also share traits with the Common Swallowtail. For example,  the adult Desert Swallowtail has 30-31 antennal segments, while the adult Common Swallowtail has 33-36 antennal segments. Most of the Lampedusa specimens had 30-31 segments but some had 33 and one had 35.

The authors note “that the population on the island of Lampedusa possesses morphological traits of both P. saharae and P. machaon, plausibly the result of a hybrid swarm…” Intriguingly, the authors state: “The Lampedusa taxon appears to be, quite literally, a species in the making through the process of natural hybridization. Papilio saharae and P. machaon are known to hybridise naturally in Israel, where the two species maintain a contemporary sympatric association (both species occur together in the same area), contrary to the case of the Lampedusa taxon (a taxon is a biological entity of any status), which has been isolated for millennia.”

The authors made the decision, based on their morphometric analysis of all our four life stages, to recognise the swallowtail found in Lampedusa as a ‘new’ subspecies of the Desert Swallowtail, proposing the name Papilio saharae aferpilaggi ssp. nov (ssp. nov. means new subspecies; the subspecies name refers to the fact that the taxon originated in Africa, hence, the use of the adjective âfer which implies “of Africa”, while pilaggi is derived from the Sicilian name of the island group,  Ìsuli Pilaggî.’)

One of the features that I did find persuasive for anchoring the swallowtail found on Lampedusa to Papilio saharae is that some of the pupae the researchers reared did not hatch but entered diapause (a delayed development used to deal with unsuitable conditions, such as extreme heat). The Desert Swallowtail pupa is known to enter diapause, sometimes taking over a year to hatch. The swallowtail in Malta, Sicily and southern Italy do not habitually resort to diapause, at least in the long term.

The swallowtail has much to teach us about how it varies across its wide range. Over 50 subspecies of Papilio machaon have been described so far, and if genetic analysis is used, some might be regarded as full species. Some might have arisen from hybridisation, geographical isolation and ecological conditions, such as climatic and habitat conditions.

One such subspecies is the British race of the Common Swallowtail, Papilio machon britannicus. It differs in appearance from the main European Common Swallowtail, Papilio machaon gorganus and it is also restricted to one habitat type and one larval foodplant. It occurs only in fens, and breeds on Milk Parsley Peucedanum palustre. In Europe, the species breeds on a range of plants, especially Fennel Foeniculum vulgare, Wild Carrot Daucus carota, Fringed Rue Ruta chalepensis, etc.

The British Swallowtail used to occur widely in the extensive fenlands in central and eastern England, but it disappeared from all but a few places near the Norfolk coast when the vast fens were drained for agriculture. Thus, the fens of Cambridgeshire are now featureless flat farmland. Its last site in Cambridgeshire was Wicken Fen, but it was lost from the fen in the early 1950s when it became too dry and probably overgrown to support the foodplant in the correct circumstances for the butterfly to use it.

The Norfolk fenlands are a big destination for butterfly lovers in England. Seeing Britain’s rarest and largest native butterfly is a big tick on one’s list. It is a powerful flyer, with a dramatic surging flight and an especially dramatic courtship flight when both sexes fly vertically into the sky until almost out of sight before descending to the ground to mate.

As you might have guessed by now, the butterfly is in grave danger. According to The Guardian, only 81 swallowtails were counted in Norfolk last summer (2023). It might be the world’s rarest butterfly.  Even worse might be unfolding. The fens are wetlands, with water typically near or at times above the surface of the ground. The chrysalis is formed low down on reeds and has been known to survive short periods of inundation. However, many East Anglian fens have been flooded since last October.

In Norfolk, the butterfly usually starts to emerge in May. Will any emerge this year? Is it about to become extinct? The situation is, to quote noted English Lepidopterist Peter Eeles, ‘absolutely shocking.’ I contacted Peter to check whether the recent report in The Guardian reflects the true situation, or whether the low number recorded last summer indicates low monitoring effort. Peter confirmed that the monitoring is of a high standard; in other words, the population is in crisis.

It is not simply that the population abundance has fallen. The distribution of the population has declined too. Between 1976 and 2019 its distribution change is -27%. This means that the butterfly has lost habitat at the rate of -12% per decade. Loss of area occupied is very serious because its shrinking distribution leaves it more vulnerable to changes in the areas it still occupies, such as the flooding since October 2023.

Bad news arises from more than one cause. The rising sea level off the Norfolk coast is increasing salinity (saltiness) in the fens; the Milk Parsley the British Swallowtail relies on needs fresh water. Salinity affects plant growth and germination. In summer droughts there is not enough water falling as rain to keep salt water out.

Milk Parsley is not the only rare plant in the fens; Fen Violet, for example, occurs there too. Some efforts to protect Milk Parsley harm other rare plants, so a conflict of priorities, common in small areas devoted to nature, is a further conservation conundrum.

Bizarrely the Red List of British Butterflies 2019 assesses the Swallowtail as ‘Vulnerable,’ not as ‘Endangered’ or ‘Critically Endangered’. In this instance, the criteria used appear to be unfit for purpose.

It is worth noting that the International Union for the Conservation of Nature (IUCN) Red Listing process is complex and statistically prescriptive. Some key points to bear in mind are that it is an assessment of extinction risk and not conservation priority, that rarity alone is not sufficient for Red List qualification and that historical declines that have ceased are not relevant. Therefore an animal that was once very widely distributed and which lost the vast majority of its distribution and population would not be ranked as under threat today if its distribution and population were stable as recently as the decade before the list was drawn up or reassessed.  One wonders when considering a numerically small population confined to a small area of at-risk habitat if another criterion/criteria can be applied to assess its status.

My instinct apart from decrying the widescale loss of fens inland would be to embark on an ambitious landscape-scale re-wetting programme to recreate suitable habitat inland to save Britain’s most iconic butterfly. Captive breeding, if not already in place (captive breeding was carried out in Monk’s Wood in the past) must be instituted immediately and maintained until the habitat is available.

Being restricted to small patches of habitat is disastrous when things go wrong. Landscapes must be protected, not sites. In this country, we cannot say we haven’t been warned.

There are hundreds of museum specimens of the British Swallowtail. Soon, that’s likely where you’ll need to go to see it.

References

Cassar, Louis-F, Catania, Aldo (2023): A new subspecies of Papilio saharae Oberthür, 1879 (Lepidoptera: Papilionidae) from Lampedusa, Italy.

Fox R, Dennis EB, Purdy KM, Middlebrook I, Roy DB, Noble DG, Botham MS & Bourn NAD (2023) The State of the UK’s Butterflies 2022.Butterfly Conservation, Wareham, UK.

The Guardian (2024) Rare Swallowtail butterfly suffers worst summer since records began Available at https://www.theguardian.com/environment/2024/jan/30/rare-swallowtail-butterfly-suffers-worst-summer-since-records-began (Accessed 13 March 2024)

 

 

 

Biodiversity Ireland Issue 2 Autumn/Winter 2023 has been published by the National Biodiversity Data Centre. Among other interesting biodiversity topics, it reports on trends in Ireland’s butterflies, giving interesting information about abundance trends in 2022 plotted against 2008, the baseline year for recording butterflies in Ireland using transects and phenology or specifically in this case, the timing of butterfly flight periods.

Just a quick reminder about what butterfly transect walking involves. In Ireland, the main flight period lasts from April to September. Accordingly, a fixed route likely to contain butterflies is walked once a week from 1 April to 30 September, and the number of each butterfly species is recorded. The data is sent to the National Biodiversity Data Centre where it is added to their database and analysed for abundance and phenology trends.

It is interesting to walk a transect, not just for the pleasure it brings but to see how nature changes through the seasons and between years. However, sometimes the findings are more interesting than we would like them to be. The National Biodiversity Data Centre has found that there was an overall decline of -57% in the number of butterflies flying in 2022 compared to 2008. This information reflects the flight data of the 15 most common butterflies. Just a reminder that 2022 was one of the warmest years globally, and Ireland had hot weather in July and August when many of our butterflies are at their flight peaks so we might have expected higher numbers. I recall being in the Burren in early August 2022, in beautiful habitats and being underwhelmed by the number and range of butterflies on show. Here is my record for 6 August 2022:

Small Copper 3, Common Blue 2, Brown Hairstreak 5 (female 1), Speckled Wood c.6, Grayling 3, Meadow Brown 28, Ringlet 2, Small Heath 2 between R 30322 94432 and R 29846 94242, Knockaunroe, Co. Clare. Sunny, breezy, c.17C.

Note the absence of Wood White, Brimstone, Small Tortoiseshell, Peacock, and Silver-washed Fritillary, among others, from the records. It is possible that the warmth of July 2022 brought an early close to the flight period of Wood White, Brimstone, Peacock and Silver-washed Fritillary. However, to see not one of any of these species is strange, especially as all these butterflies (apart from Wood White) were being recorded elsewhere in Ireland at that time.

Regarding individual butterfly species, 12 of the 15 showed declines since 2012, two (Brimstone and Holly Blue) showed stable trends, while one, the Peacock, showed an increase. Numbers of some grass-feeding species, such as Speckled Wood, Meadow Brown and Ringlet show dramatic falls since 2008. Cryptic Wood White, Orange-tip, and the three common whites show big declines too. The decline in the numbers of common butterflies is worrying because these are mobile, have a range of caterpillar foodplants or one or two very common foodplants and are not confined to habitats that are restricted in Ireland, like limestone pavement or ancient woodland. Such declines suggest that the general environment is becoming less hospitable to wildlife generally.

What about the less common butterflies? There is less data for these, but the data suggests that Dark Green Fritillary, Wall Brown and Grayling have a slight downward trend, while Dingy Skipper looks stable. The report does not provide data for the other less common butterflies, like Pearl-bordered Fritillary, Marsh Fritillary or any of the hairstreaks.

The 2022 season shows that the peak of the flight periods occurred two weeks earlier than the peak seen in 2021. The increased heat in 2022 is likely responsible for this difference. While some butterfly species (Speckled Wood, Meadow Brown and Small Heath are examples ) will emerge over a lengthy period, spreading the risk of emerging in bad weather over several weeks and even months, prolonged warmth and high levels of direct sunshine may result in larvae of some species developing faster and more reaching maturity together, culminating in a mass emergence over a shorter time.

This can be risky if a mass emergence is in progress and a prolonged spell of bad weather strikes. I have seen this happen to the Marsh Fritillary on my transect on Lullybeg Reserve. A population crash occurs the following year because only a small number of individuals get to produce offspring. Recovery occurs over time, but in some cases, the entire population is wiped out. This is not disastrous when the population is functioning properly because the unoccupied site will be repopulated from a nearby colony. The problem arises when there is no nearby population.

The article does not dig into the reasons for the population decline. The reasons are deeper than weather conditions, relating to habitat availability, quality and likely, pollution from intensive farming and industry.  That is for another post.

If you would like to establish a transect close to where you live to help monitor our and your butterflies, please email our recording partners: butterflies@biodiversityireland.ie

 

We must postpone the reserve management event planned for Saturday 24 February. The weather has been extremely wet, and the access routes are in very poor condition. Apologies for any inconvenience.

On the plus side, some Marsh Fritillary caterpillars on the reserve are out of hibernation. We look forward to counting and monitoring them over the coming weeks.

Butterfly Conservation Ireland’s reserve’s butterflies continue to thrive (see the reserve report in our Annual Report: https://butterflyconservation.ie/wp/butterfly-conservation-ireland-annual-report-2023/), even though the National Biodiversity Data Centre analysis of the 15 most common butterfly species show a -57% decline in the number of butterflies flying in 2022 compared to the baseline year of 2008.

A special thanks for the continued support from all our members and friends.

Butterfly Conservation Ireland Annual Report 2023 is now available at https://butterflyconservation.ie/wp/butterfly-conservation-ireland-annual-report-2023/

We hope you enjoy this report. A free hard copy is available to all members on request. We are looking forward to the butterfly season in 2024 which we will report to you early in 2025.