Butterfly Conservation Ireland

The oak has a long and venerable history in Britain and Ireland. We tend to have an affection for the plant, probably because of its famed longevity. I recall seeing an oak plantation in the Nagshead Nature Reserve in the Forest of Dean, Gloucestershire. The Royal Navy ordered the cultivation of the trees to ensure the high seas fleet had access to oak timber in the years to come. The trees were planted during the Napoleonic Wars 1803-1815, commencing in 1811. 11,000 acres were enclosed for the plantation, which was ordered on foot of a report by Admiral Nelson who expressed alarm that the natural regeneration of oaks was being prevented by hogs that consumed the acorns and deer which barked the trunks of existing trees.

When I stood back and looked carefully, I realized that despite appearances, the woodland at Nagshead is not a natural wood. The trees are even-sized and in rows. The trees have good, straight trunks from which to fashion ship planks and are now ready for harvesting.

In 2004, Admiral Nelson’s flagship, Victory, was refurbished using two of the oaks, in time for the bicentenary of the Battle of Trafalgar in 2005. The victory was commemorated in the Forest Of Dean, including at the Easter Sunday Service in Lydney in 2005.

Today, the oaks continue to grow, unharvested, no longer needed for the defence of Britain. The area is still government property, run by Forestry England, but as a nature reserve.  Both oaks native to these islands, Sessile Oak Quercus petraea and Pedunculate Oak Quercus robur grow there.

Unlike the situation in England, Ireland is highly deficient in oak woods. Nearly all the oak woods are of Sessile Oak, located in upland areas in Wicklow and Kerry, and often species-poor in terms of the ground flora. The ground flora on these acid soils are typically limited; in Wicklow, the ground flora is often dominated by a dense thatch of Great Wood-rush  Luzula sylvatica with Bracken Pteridium aquilinum, ferns and mosses.

Oak woods on fertile lowland soils are very rare in Ireland.  This woodland type is known as oak-ash-hazel woodland. These deep, fertile soils rarely hold this native woodland, used instead for grazing livestock and for crops.

Where this woodland exists, the result is often a rich ground flora.  The composition of the ground flora varies and may include Ivy Hedera helix, Wood Anemone Anemone nemorosa, Bluebell Hyacinthoides nonscriptus, Wood Avens Geum urbanum, Sanicle Sanicula europaea, Early Dog-violet Viola reichenbachiana, Lords and Ladies Arum maculatum, Ramsons Allium ursinum, Wood Speedwell Veronica montana,  Barren Strawberry Potentilla sterilis, Pignut Conopodium majus, False Brome Brachypodium sylvaticum and ferns (Dryopteris filix-mas, Polystichum setiferum, Asplenium scolopendrium, Athyrium filix-femina.)

One example is the ancient wood at Charleville, Tullamore, County Offaly. This wood is remarkable for its highly impressive ancient oaks, especially the most famous Pedunculate Oak in Ireland, the “King Oak.” Even the merest glimpse lets you know that you are gazing at greatness. Massive trunk, long-limbed, and lustily luxuriant foliage, it survived a lightning strike in 1963 that left a wound but this resilient behemoth overcame this shock. It has some help; it is fairly sheltered by its neighbours and some of its lower branches are buttressed. One of the lower limbs is over 76 feet long.

Unlike its younger, more upright fellows, the king no longer produces an abundant acorn crop. The King’s reign appears to be of several hundred years duration already. One expert has speculated that it may be 800 years old.  There is no signage to describe its magnificence and importance. Why not?

There are other large oaks in the wood, and some individuals have been aged by tree-ring counts at between 350 and 450 years old. These trees are considered to be indigenous Quercus robur. In an era when we are supposed to be protecting our indigenous biodiversity, buying oaks from nurseries may be deleterious to our remaining indigenous stock, because the acorns often originate in Germany and The Netherlands. Collect your own acorns from the ancient oak wood closest to your locality to continue the aboriginal stock.

Another oak wood type is wet pedunculate oak-ash woodland. This type occurs on seasonally flooded soils. This type has a tall ground flora, consisting of plants that like water-logged or wet soils like Meadowsweet Filipendula ulmaria but also plants of drier conditions like  Primrose Primula vulgaris, Common Dog-violet Viola riviniana, Enchanter’s-nightshade Circaea lutetiana, Ivy and Bramble Rubus fruticosus agg. Examples are the woodland along the River Barrow near Borris, County Carlow, Garryland Wood, County Galway, and The Gearagh, County Cork.

All three oak wood types are interesting and rich in biodiversity. Oak trees allow light to reach the ground, vital for encouraging ground flora and associated insects.  The leaves,  flowers, and acorns are very important food for a wide range of invertebrates and birds. Ireland’s oaks directly support at least 67 species of macro moth (they use it as a larval foodplant) and one butterfly, the Purple Hairstreak, a highly localised species given the limited distribution of its habitat. In addition, many micro-moths use oaks for food too.

In addition, other species use oaks for food but in a less direct manner. Sap bleeds are eagerly fed on by Red Admirals, while the aphid ‘honeydew’ secreted on the leaves during July and August are fed on by many insects, including the Holly Blue, Purple Hairstreak, and Comma butterflies. The Silver-washed Fritillary lays its eggs on oak trunks which ideally contain deeply fissured bark on which the butterfly can conceal eggs and where the caterpillar can hibernate.

The leaf litter warms the vegetation that develops around the litter in spring, which is ideal for the caterpillar of the Silver-washed Fritillary which needs warmth around its violets to develop. The leaf litter is also fed on by some invertebrates, including some moth larvae.

The shelter in oak woods provides a refuge for a vast range of species. Extreme temperatures are kept at bay, with a narrower range of warmth and coolness than open grassland. Thus, the woods are great for hibernating moths and butterflies. The Comma shows signs of being adapted to spending its winter in oak woods; the lobed wing outline and dead leaf underside hues help it blend among fallen oak leaves.

The large number of moths using oak leaves for the larval foodplant is a great draw for woodland birds seeking protein to feed their young in spring. The larvae typically start to feed on the leaves shortly after the leaves burst from their buds in spring. Oak woods are incredible places for bird song in spring and early summer, seemingly bursting with life. Sometimes nature in an oak wood surges into overdrive with serious defoliation of the trees. When this happens, the tree looks doomed but reserve buds produce new leaves and the tree survives. Old woodland that has been allowed to grow for a long time will usually have a mix of old and younger trees, resulting in a range of canopy heights, an understorey of younger or smaller tree species, a shrub layer and ground flora. These habitat layers add to the biodiversity of a woodland.

If you want to see how important our native oak woods are, take a spring walk through a coniferous plantation, typically Sitka Spruce Picea sitchensis and Lodgepole Pine Pinus contorta, alien species. These woods are even-aged, of uniform height, extremely quiet, and empty, with little or no ground flora.

Sadly, some of our oak woods contain some plantation forestry and non-native invasive shrubs, especially Cherry Laurel Prunus laurocerasus and Rhododendron Rhododendron ponticum which seriously damages biodiversity. Non-native deciduous trees, such as Sweet Chestnut  Castanea sativa Sycamore Acer pseudoplatanus,  and Common Beech Fagus sylvatica, do not help either, especially the latter two species, which are highly invasive and have a far lower number of associated invertebrates.

You can help by growing our native trees grown from seed from ancient sources obtained locally. If you are lucky to have plenty of space, plant a native woodland, using the nearest native wood as your template to determine the species that are naturally occurring in your area. If you have a farm but do not want to plant a woodland, plant oaks in your hedgerows and let them grow.

If you have a typical garden, try to grow one or two native trees; there are smaller trees and tall shrubs that can be accommodated: examples include Common Hazel Corylus avellana, Rowan Sorbus aucuparia, Common Holly Ilex aquifolium, Irish Whitebeam Sorbus hibernica, Common Yew Taxus baccata, Common Spindle Euonymus europaeus, Guelder Rose Viburnum opulus, Alder Buckthorn  Frangula alnus and Common or Purging Buckthorn Rhamnus cathartica.

These plants greatly trump non-natives in attracting our butterflies, moths, and other invertebrates, but use plants grown from native seed and cuttings. We destroyed our lowland oak woods. Let’s put them back.

All photographs copyright J. Harding

October is not the happiest month of the year. Mud-coloured clouds, autumn deluges, diminishing light, and declining warmth signal winter’s onset. The skies are darkening in the global environmental, economic, and political realms too, with little to relieve despondency. Reminders abound that all things must pass, including the happiest experiences of life, and loved ones so deeply missed.

Butterflies are our most beautiful creatures.  Aesthetic delight is the antidote to the gloom, brightness that creates hope. Over the years, we have received wonderful accounts about how butterflies helped people to see hope in extreme sadness, particularly at funerals where the sight of a butterfly fluttering around a coffin or alighting on it, inspired faith when all seemed dark.

Recently, a Small Tortoiseshell butterfly danced about the coffin of a relative of my wife’s family. Recalling many accounts I heard over the years, I pondered the meaning of this event.

I lack the skill to shape my response to mystery, but there are some, like the poet Vivienne McKechnie, with the gift to interpret such experiences. In  A Butterfly’s Wing,  Vivienne explores finding hope amidst grief. Vivienne interprets the sustaining power of beauty and powerfully presents the butterfly, a delicate being, as a metaphor for possibility, resilience, and strength. Taken from her first collection, A Butterfly’s Wing, the eponymous poem following says so much. Enjoy this reflection.

A BUTTERFLY’S WING

Now I linger, looking longingly at every winged being,
knowing the impossibility of a hug,
knowing the fragility of love,
knowing the swiftness of life’s flight.

Now, never thinking of you in the earth,
I see you everywhere.
You, who did not lie down willingly,
but who life took in a sudden stroke.
I, who could only stroke your hand and watch
appalled as you slipped the noose of life
and left me numb.
You were silent and elusive, transient
as the butterfly which appeared at your funeral.
It rose delicately out of the lilies which adorned your coffin
allowing me the poise and sustenance of sudden beauty
to read for your departure.

Now I linger, looking longingly at the Painted Lady
which touches the petals of the rose
and realize that in the fragility of a butterfly’s wing
there is strength enough to fly.

Vivienne McKechnie

Reproduced with the kind consent of Vivienne McKechnie.

 

 

 

 

 

 

 

Miss Earth Ireland is an environmentally-themed beauty pageant that promotes conservation and sustainability. This year’s winner of Miss Earth Ireland, Alannah Larkin from Galway, will represent Ireland at the final in The Philippines.

Alannah and her mother visited Lullymore in search of butterflies and beautiful habitat. Happily, the weather held good so Alannah was able to enjoy the late summer flora, especially the blue haze that radiated from the mass blooming of Devil’s-bit Scabious.

Alannah, whose favourite butterfly is the endangered Small Blue, is planning to promote the cause of butterfly conservation through her social media output.

Butterfly Conservation Ireland congratulates Alannah for her success in the competition and we wish her every success in the Miss Earth final in November.

I will lead them up and down. (III. ii) Midsummer Night’s Dream

In the 1992 EU Habitats’ Directive, member states of the European Union were obliged to protect from harm certain habitats. Member states were to submit sites to the EU as Special Areas of Conservation (SAC), according to criteria drawn up by the EU. The Directive was transposed into Irish law in 1997. Some bogs both raised and blanket bogs were designated as SACs. These are to be maintained and in some or even in all cases restored to the condition needed for full ecosystem functioning.

6,345 sq. km. of our land is designated as an SAC or 9% of the land area of the Republic of Ireland.

So much for what was supposed to happen. Now the truth.

The SAC bogs, instead of being maintained, are being destroyed by mining operations, reducing the bog area until in many cases the bog no longer corresponds to the criteria for which it was designated as an SAC. There are now moves to de-designate some of the SAC bogs that have been destroyed.

This ongoing damage is well-known to the Irish Government. Here is an extract from the National Parks and Wildlife Service (NPWS) description of All Saints’ Bog SAC:

An extensive area in the north-east corner of the bog, representing about 20% of the bog surface, is being cut for turf, with drains running into the eastern edge of the birch woodland. This appears to be leading to the bog drying out, as the surface is reported to be much drier than when first surveyed in the mid-1980s. (https://www.npws.ie/sites/default/files/protected-sites/synopsis/SY000566.pdf)

The damage is ongoing and is observed by NPWS using drones and aircraft, but nothing is being done. The steady march to oblivion of our national heritage is being ‘monitored.’

There is a weak scheme dated July 2021 called the Protected Raised Bog Restoration Incentive Scheme (PRBRIS) which is a voluntary scheme for owners and those with turf-cutting rights. This scheme offers payments to owners and those with turf-cutting rights whose land is within an SAC or National Heritage Area (NHA). These can opt to sell the land to the state or accept compensation for not cutting the bog (see https://www.npws.ie/sites/default/files/files/prbris-terms-and-conditions-english.pdf). The document states the cessation of peat-cutting and non-interference with the bog hydrology must be in perpetuity for its land management agreement scheme.

According to The Irish Farmers’ Journal (https://www.farmersjournal.ie/state-paying-up-3-700-ac-for-raised-bog-721076) around 59 acres of raised bog have been purchased since 2020, a mere 23.9 hectares.

Why does the state not purchase the raised bog SACs and National Heritage Areas (NHAs), and avoid the damage being wrought on our most sensitive habitats? The EU Commission has finally lost patience with the Irish Government (after warning the Irish Government about its inactivity since 2011) and on September 29th, 2022 it threatened to refer Ireland to the Court of Justice of the European Union within two months unless the Government takes effective action to halt the continued cutting of peat within Special Areas of Conservation (SACs) designated to conserve raised bogs and blanket bogs under the Habitats Directive.

The Commission notes:

cutting activities are still ongoing and enforcement action appears to have stalled. Restoration activities have begun on some raised bogs SACs, but this is too slow given the importance of this priority habitat and its precarious state. With regard to blanket bogs SACs, there appears to be no regime controlling ongoing cutting with the cutting for domestic use exempt from control.

(https://ireland.representation.ec.europa.eu/news-and-events/news/commission-calls-ireland-halt-peat-cutting-activities-natura-2000-sites-and-restore-these-sites-2022-09-29_en)

The Commission has dragged its feet too, despite numerous complaints from Irish citizens and organisations. Soon there will be no bogs left to protect, and the issue will be dropped.

That is my personal reading of the situation and appears to be how turf-cutter representatives see it too. Recently, a spokesman for turf cutters countered calls for cutting to stop by saying that “It is coming to an end anyway.” It is coming to an end because the bogs are almost gone.

We are being led up and down. The Government has no interest in biodiversity, carbon absorption, flood and pollution control, or the rule of law when it comes to the environment, just doing as little as possible and getting away with it.

Without a dramatic change in attitude, there will be no chance for our bogs. Let us hope that attitudes don’t change when it is too late.

Attitude lies at the heart of this existential crisis for our bogs. Bogs have often been ignored or dismissed. Even the great naturalist and botanist, Robert Lloyd Praeger, had nothing positive to say about Ireland’s bogs:

Offaly…is the most bog-covered part of the Central Plain, no less than one-fifth of its area buried under that strange vegetable blanket. But the remainder makes up for this by being often pleasant well-farmed country, with plenty of trees and some good towns. (The Way that I Went, p. 237)

Praeger was and is wrong. Bogs are crucial habitats for rare biodiversity, such as the Eurasian Curlew, Merlin, Hen Harrier, Eurasian Skylark, Meadow Pipit, the Large Heath butterfly, a range of mosses and other bog specialist plants like Bog Rosemary. The area just above the bog surface teems with activity from late April to October, with bees, flies, moths and butterflies with the soundtrack of bog birds, from the Cuckoo to Willow Warbler, adding aural texture and warmth to the wilderness experience of an undulating habitat extending to the horizon, engendering a feeling of being a small individual in a vast void, with nothing between you and the sky. It is a landscape of dreams, of imagination, of escape from today’s bland, impoverished agricultural land where little remains of wildlife that once found their homes on the farm.

Do not buy peat, wherever it comes from, in any form, for any purpose. This defends our peatland heritage although it must be admitted that for most of our bogs, it is too late to save them as they were when R.L. Praeger dismissed them in the 1930s.

All Photographs by J. Harding

 

 

 

Butterfly Conservation Ireland’s reserve at Lullybeg in County Kildare is one of only two reserves in Ireland managed with the needs of butterflies as the main priority. The other example is located nearby in Lullymore West, managed by the Irish Peatland Conservation Council.

Both reserves contain mosaics of grassland, scrub, woodland, and open water. In addition, Lullybeg Reserve contains bare peat and marl soil, which is very beneficial for butterflies. Both areas support orchids, which are mentioned not because these are particularly important for butterflies but because orchids are generally indicative of ecological richness.

Grazing and scrub control is applied on the reserve to maintain open habitats. These are rich and varied on Lullybeg; applying level 3 of the Fossitt Classification Codes and Descriptions, the grasslands/heath that Lullybeg contains are wet grassland (some is calcareous and in places wet grassland grades into poor fen and flush), dry-humid acid grassland, marsh, and wet heath.

These habitat conditions provide a home for a high range of moths and butterflies as well as hundreds of other invertebrate species.

A bumper Marsh Fritillary population during the flight period in May and June is indicated by a transect count of 95 Marsh Fritillaries on the 27th of May with many other Marsh Fritillaries present elsewhere on the reserve outside the transect line (a transect is a fixed route where butterflies seen 2.5 metres on either side and 5 metres ahead are counted). A search on the 28th of August revealed 73 Marsh Fritillary larval nests, with a further nine nests on the ground directly adjoining the reserve located on the 1st of September. This figure of 82 larval nests represents the highest abundance yet recorded on the reserve and vicinity.

The positive conservation outcome does not end with the Marsh Fritillary butterfly’s upward trajectory, which has been building steadily from a low point in 2015.

The Marsh Fritillary breeds on a perennial flower called Devil’s-bit Scabious. The Marsh Fritillary caterpillars feed mainly on the basal leaves of the plant. The plant produces many nectar-rich flowers on branched stalks. These are in bloom mainly in August and September and into October. Because the plant which is abundant on the reserve produces a mass of flowers throughout late summer into mid-autumn, the reserve is very attractive to late-flying butterflies and moths.

One of the late flyers is the Comma butterfly. This species was not part of our butterfly fauna until the early 2000s, when it colonized the extreme southeast of Ireland, probably from southwest England. It was confirmed breeding in Ireland only in May 2014 and is spreading northward and westward. In 2019 the Comma was seen on the reserve when just one was seen. No Comma was seen there in 2020 and 2021, but several have been seen on the reserve this year, with 12 Commas seen on Devil’s-bit Scabious on the reserve on the 24th of September 2022, after five were observed on September 20th.

This abundance strongly suggests local breeding. It might be using nettles on the reserve or nearby, perhaps on nettles growing on the bank of the Crabtree River. Unlike its relatives, the Small Tortoiseshell and Peacock, the Comma is rarely found in abundance so finding 12 individuals on the site is noteworthy.

After feeding for a few days, the Commas will settle deep in wooded cover, wings closed, until spring. There is an abundance of such cover on the reserve, so it is expected that the butterfly will use the wooded habitat for over-wintering as well as feeding up for their long sleep on the open grasslands.

This autumn the Red Admiral has been present in good numbers too, feeding alongside the Comma. But the Red Admiral has a different strategy for dealing with the long, cold, nectarless months: migration. When the reserve’s Red Admirals are well stocked with nectar, they will fly south, making landfall in warmer parts of Europe where they will breed. Red Admiral migration certainly occurred between September 20th when 41 were counted and September 24th when just six remained.

I saw what must have been a migration flight by a Red Admiral on the 24th of September 2022. It flew up from Devil’s-bit Scabious, directly over my head, and flew strongly upwards in a southerly direction until it vanished from sight. It began its upward flight at a c. 45-degree angle, ascending afterward at about 60 degrees, and before disappearing from view its angle of ascent increased. The wind was northerly, about force 2-3 on the Beaufort Scale, ideal for a southbound butterfly.

These are just some of the highlights from the reserve. You can read a more comprehensive report on the reserve’s progress in our forthcoming Annual Report 2022.

In all the maelstrom of climate change and biodiversity loss, it is so heartening to hear positive voices express hope for a better, happier, more nature-rich future. I heard these voices recently on the video linked here:

This wonderful group of young people teamed up to produce this wonderfully evocative, earnest and touching innocent plea for the preservation of the great wilderness and biodiverse paradise in northwest Kildare and east Offaly. The group is supporting the campaign for a new National Park to be located in the region. This would be the only national park in Ireland on raised bog habitat.

The young people will make their pitch to Kildare County Council on the 24th of October 2022 when they will meet all of Kildare’s councilors.

Butterfly Conservation Ireland asks you to support this vital proposal, which encompasses around 7000 hectares of habitat, by signing the petition at www.noplanetb.ie

The development of a national park in this area will enhance the protection of Ireland’s biological diversity, reduce pollution, store carbon and promote carbon sequestration. The tourism, commercial and amenity potential possibilities present opportunities for local communities and businesses in Kildare and Offaly.

The opportunities include the potential for rambling, cycling, horse riding, water sports, nature study, education, and research. The  Park will offer people a wilderness experience. Situated in the east midlands, it has the potential to attract visitors from the greater Dublin area and overseas, bringing opportunities to an economically depressed West Kildare /East Offaly area.

But it will do so much more; it will give hope to all who love our landscapes, want to see despoilation and biodiversity loss reversed, and see the faith of our idealistic young people affirmed.

Sign the petition!

Below are some adult moths (and one caterpillar) that are active during September. ‘Foodplant’ and ‘breeding plant ‘refers to the plant eaten by the caterpillar. The following moth species are nocturnal.

All images J. Harding

Calm, mild September nights often yield large populations of moths. A car journey home at around 10 pm along our rural hedged roads will often give an indication of the level of abundance, with ghostly wings flitting in and out of view in the car lights. A glance upward at hedge-top height might reveal bats that will dip down to snatch a moth meal. Some moths are disorientated by light and will flutter against the base of hedges, kerbs, or walls that the light falls on. If a car is parked with lights on for some minutes, these moths can fall prey to frogs and hedgehogs emerging from cover nearby.

Moths are very important food web components. A healthy moth population is a sign of environmental health. When you see plenty of moths in your headlights, feel good about the area you are in!

 

 

September is an in-betweener, no longer summer but with some days bringing summer heat, not winter but with some sharp cold at night. The blooms of summer have mainly faded but new flowers offer sustenance to September moths and butterflies. Some fruits are available too; Rowan, bramble, and Elder offer their sweetness to species still in flight.

Oddly, September is a peak month for some species: Red Admiral, Comma and Speckled Wood are abundant in September.  Yesterday I counted 54 Speckled Woods in the rather cool, breezy Russellstown Wood, near Russborough House, in County Wicklow.  The butterfly is also extremely abundant in the scrublands of the Burren, where its copiousness astonishes, an apparently seasonally discordant richness.

Speckled Wood eggs being laid now are unlikely to produce pupae before winter, but the larvae will pupate next spring or early summer depending on development rates. The resulting adults are likely to fly in May and June after their aunts and uncles have flown in March, April, and early May. This prolonged emergence arising from individuals from more than one generation from the previous year provides a very long first brood, running from later in March to the end of June.  A gap occurs in the flight of this species during July, with few flying in this month. However, from August lasting well into September and even October, there is an extended emergence resulting from larvae produced during April-July. According to Thomas and Lewington (2014) not all spring larvae produce second-generation butterflies. Some develop slowly and form over-wintering pupae in autumn.

The understanding of the Speckled Wood’s complex brood structure comes from studies done in Britain. Perhaps this applies to our Speckled Woods, but until breeding studies are undertaken in Ireland we cannot confirm this. While our records of the adult butterfly suggest that the butterfly has a similar brood structure here, when I reared the species from eggs laid in late June, all of these reached adulthood in late August and during September. If some spring larvae do not produce butterflies in the same year, do some summer larvae undergo slower development, producing over-wintering larvae or over-wintering pupae in autumn?

I suspect that there is more to learn about the Speckled Wood’s brood structure in Ireland, potentially including regional differences in its development rates.

Another species with a complex brood structure is the Comma, and in parts of Ireland where it is established, it is present in good numbers, feeding on autumn fruits and late flowers to store up fat for its long sleep. Unlike the Speckled Wood which over-winters as a larva or pupa, the Comma passes the autumn and winter in just one life stage, the adult stage.  With its dark, bark-coloured undersides and scalloped oak-leaf outline, it is perfectly placed to conceal itself in woods, on tree trunks, and among heaped leaf litter. By contrast, the bright orange uppersides now illuminate hedged country lanes, wood edges, clearings, and gardens. When a vivid example is perched on blackberries, the luminosity is striking. When the sun is obscured and sometimes when it detects approach, it shuts its wings and becomes a dead leaf trapped in the bramble.

The tiny Small Copper is still adorning our grasslands and the warm sunny August and pleasant September might see the third generation later this month. Two broods are seen each year with the third generation weather-dependent. Today (September 17th) I saw the pristine female shown in the photograph below. Shortly after I took the photograph, she was courted by two males. Her offspring will fly next year’s first generation, typically in May and June.

Another gorgeous butterfly, the Red Admiral, is present in our countryside and gardens, and in some abundance in flower-rich areas.  It has a broad taste, taking advantage of nectar, fruit juice, and tree sap. By contrast with the previous butterflies profiled here, this will leave our shores this autumn to breed further south, in Europe. A few stay behind to breed in coastal areas but this applies to a small number of individuals, as far as is known.

For now, enjoy this black and scarlet butterfly. It will fly throughout September and October, relying increasingly on ivy nectar as other food sources disappear.

The Small Tortoiseshell rounds off this article. This bright, friendly-looking butterfly is busy feeding up to spend the winter as an adult butterfly. Unlike its relative, the Comma, the Small Tortoiseshell will seek out buildings as well as natural places to over-winter. Like the Comma, its undersides are muted in colour blending it with the dark places chosen for over-wintering. All over-wintering butterflies close their wings when sleeping, so colourful uppersides are not on show. Like all species that over-winter as adults, the Small Tortoiseshell does not enter this state synchronously; rather individuals enter the over-wintering state over several weeks, so the individuals seen at any time during August-October represent those yet to close their wings for the year. This elucidates the paradox of seeing more individuals in spring than appear to have been active during the previous late summer and autumn.

If you are lucky to host a Small Tortoiseshell this autumn or winter, do not release it. Relocate any woken by the central heating to a cool place such as a shed or even a kitchen roll-lined Tupperware box with the lid on, placed in the fridge (never the freezer). Release the butterfly in warm, sunny weather in March. The individual in the photo below has traces of gossamer on its wings resulting from an encounter with a spider’s web. It overcame this survival challenge. Will it survive our long, dark foodless winter? For Small Tortoiseshells that take refuge behind our cupboards, wardrobes, picture frames, mirrors, and within curtain folds, that is for you to decide…

All photos by Jesmond Harding.

Key Reference

Thomas, J. & Lewington, R. (2014) The Butterflies of Britain and Ireland. (Revised edition) British Wildlife Publishing, Dorset.

 

The Burren is a region in North County Clare and South Galway. It is a karst landscape containing exposed limestone. The Burren as it appears today is mainly the result of the last glaciation and the impact of human activity, especially farming. It is a remarkable landscape, containing a variety of habitats that belies the seeming uniformity of appearance when viewed from a distance, particularly during winter. In addition to eye-catching geological features, the area has a range of habitats that add enormously to the region’s biodiversity and international reputation. This article focuses mainly on the value of scrub and limestone grassland for butterflies and moths, particularly in areas where these habitats exist close together.

Scrub is a broad term and includes areas that are at least 50% covered by shrubs, stunted trees or brambles. The term includes dense growth with little ground vegetation. The canopy height is usually below 5m. The scrub of most value to butterflies is open scrub on lightly grazed, herb-rich grassland that receives good sunlight. Scrub management is carried out by occasional burning, manual cutting or cutting using machinery, sometimes followed by herbicide application. The most important habitat in Ireland for butterflies is the open scrub on calcareous grassland in the Burren in County Clare and Galway. The main scrub components present in the Burren are Common Hazel Corylus avellana, Common Hawthorn Crataegus monogyna, Common Blackthorn Prunus spinosa, Bramble Rubus fruticosus agg. and erect or scrambling roses Rosa spp., in addition to several willows Salix spp., Ling Calluna vulgaris, Guelder Rose Viburnum opulus, Common Holly Ilex aquifolium, occasional Juniper Juniperus communis and Common Yew Taxus baccata.

The grassland in the Burren clearings is often rich in flora, especially clovers Trifolium spp., violets Viola spp., Common Knapweed Centaurea nigra, Devil’s-bit Scabious Succisa pratensis, Selfheal Prunella vulgaris, Common Bird’s-foot Trefoil Lotus corniculatus, Cat’s-ear Hypochoeris radicata, Lady’s Bedstraw Galium verum and Oxeye Daisy Leucanthemum vulgare. The more calcareous grasslands are characterised by broadleaved herbs such as Cowslip Primula veris, Greater Knapweed Centaurea scabiosa, Kidney Vetch Anthyllis vulneraria, Mountain Everlasting Antennaria dioica, Yellow-wort Blackstonia perfoliata, Salad Burnet Sanguisorba minor and Carline Thistle Carlina vulgaris, and may also be important for orchids, including Ophrys and Orchis spp.

Grasses present often include fescues Festuca spp., Sweet Vernal-grass Anthoxanthum odoratum, Crested Dog’s-tail Cynosurus cristatus, Cock’s-foot Dactylis glomerata and Yorkshire-fog Holcus lanatus. Grasses that are indicative of strongly calcareous soils include Downy Oat-grass Avenula pubescens, Yellow Oat-grass Trisetum flavescens, Blue Moor-grass Sesleria caerulea and Quaking-grass Briza media.

These scrub and grassland mosaics are used for breeding by scrub/woodland and grassland butterflies. The butterfly species recorded breeding on herbs and grasses in open scrub in the Burren are Dingy Skipper Erynnis tages, Wood White Leptidea sinapis, Common Blue Polyommatus icarus, Small Tortoiseshell Aglais urticae, Peacock Aglais io, Red Admiral Vanessa atalanta, Painted Lady Vanessa cardui, Pearl-bordered Fritillary Boloria euphrosyne, Dark Green Fritillary Speyeria aglaja, Silver-washed Fritillary Argynnis paphia, Marsh Fritillary Euphydryas aurinia, Speckled Wood Pararge aegeria, Wall Brown Lasiommata megera, Grayling Hipparchia semele, Meadow Brown Maniola jurtina, Ringlet Aphantopus hyperantus and Small Heath Coenonympha pamphilus.

The species recorded breeding on shrubs in open scrub in the Burren are Brimstone Gonepteryx rhamni, Brown Hairstreak Thecla betulae, Purple Hairstreak Favonius quercus, and Holly Blue Celastrina argiolus.

Separating the species breeding in open scrub into (a) herb/grass feeders and (b) species feeding on shrubs ignores the complex habitat associations of several of the species listed here. The shade, shelter, and leaf litter provided by scrub influence conditions in the grasslands. This is vital for Lepidoptera, especially for the life stages lasting several months. The role played by scrub varies according to species, the time of year, and features such as the height, structure, composition, and management of the scrub and sward.

The Marsh Fritillary is a locally distributed, generally scarce species that requires grassland containing at least a 25% density of the larval foodplant Devil’s-bit Scabious, with the plants growing close together. The grassland that is most favoured has a sward height of 12-25cm. Some occupied swards are taller and even quite rank, but the foodplant is unshaded. The sward usually has tussock-forming grasses and flowers. There is usually some light cattle or horse grazing to maintain the grassland. In swards that are strongly exposed to the weather and that are moderately grazed during the summer, some sheltering scrub is important for the Marsh Fritillary. This species dislikes exposed grasslands unless there is a tall, (c.25cm) well-developed sward that is grazed irregularly and extensively or throughout the year if grazed extensively. Litter from easily warmed dead vegetation, especially from grasses, but sometimes from mosses, scrub foliage, and bracken, must be present for the Marsh Fritillary to be able to make use of the sward for breeding.

The scrub is also used by the Dark Green Fritillary. This eye-catching, dynamic species flies mostly from mid-June to mid-August. Eggs are laid on or near violets growing in grassy places with a fairly tall, well-developed sward, in open, exposed grassland, in sunlit clearings in open scrub, but also at the immediate edge of scrub where a lower, patchier sward exists. After about two weeks, the newly hatched larva eats the eggshell and immediately enters diapause (a rest phase with no feeding and little development), remaining in this state until March of the following year. Unless it has the shading effect of a well-developed sward or scrub, the unfed larva will desiccate in the summer heat.

The Wood White has a highly restricted distribution in Ireland, where it has been found only on carboniferous limestone, from near Newmarket-on-Fergus in south County Clare northwards to Lough Corrib, County Galway on its east and west shores. Its stronghold is the Burren. It is scrub-dependent, breeding on vetches, especially Meadow Vetchling and Tufted Vetch, that receive direct sunlight but that grow in intimate contact with scrub. The adult has a weak, fluttering flight, and the shelter afforded by scrub appears necessary for it. The larva needs access to direct sunlight, shelter, and shade throughout its development. When feeding is complete, it pupates in the scrub or on vegetation growing among the scrub. Medium-tall vegetation in intimate contact with scrub is crucial for this species.

In Ireland, the Pearl-bordered Fritillary breeds on Common Dog-violet Viola riviniana growing among open scrub and open woodland on the carboniferous limestone in the Burren, Counties Clare and Galway, and in similar habitat near the Burren. In Ireland, it is restricted to these areas. According to Nash et al (2012), it has been recorded in just twelve 10 km squares, 35 tetrads. In two of the 10km squares, on Inishmore and Inishmaan, where single individuals were seen, it appears that these were wanderers from the mainland.

The breeding habitat for the Pearl-bordered Fritillary is the same as that used by the Wood White. The larva requires shade and direct sunlight. Direct light is required by the larva for it to be active and for digestion while the shade is needed to cool it down. During hot sunny weather in summer, the larva feeds in strong sunlight but quickly retreats to a shaded location. Cooling shade is needed during the larva’s long diapause from mid to late summer until feeding resumes in March. Furthermore, unshaded violets wilt and turn yellow, which makes make them unsuitable. In part-shaded areas, the foliage remains green.

The question of why the Pearl-bordered Fritillary’s distribution in Ireland is limited to the Burren is an interesting one, with the answer likely to be found in the conditions needed by the larva. It needs the Common Dog-violet, usually with low herbs and dry moss on dry, free-draining, warm, sheltered, usually south-facing sunny habitats containing leaf litter build-up against scrub on open limestone rock. The larval micro-sites have low grass density; the grasses present are typically scattered tufts of Blue Moor-grass and fescue grasses containing standing and lying warm, dry litter, particularly in spring. Plant litter is used by larvae for basking, concealment, and over-wintering. It may be important for the larva to have Common Hazel leaf litter. Hazel produces a leaf litter that is substantial without shading the foodplant. Dead hazel leaves curl, producing hiding places for resting larvae. The dead leaf dries quickly, and the larva needs dry conditions (Harding 2021).

Two other features favouring the species are the frequent rainfall that prevents the foodplant from losing moisture while the free-draining limestone provides the dryness needed by the larva. Grazing by cattle or horses during winter and spring, and periodic scrub cutting, but not scrub clearance, is beneficial.

The adult feeds mainly in the clearings in the scrub, especially on Common Bird’s-foot-trefoil, Bugle Ajuga reptans, buttercups Rununculus spp., and Dandelion Taraxacum spp. Thus, the butterfly needs the grassy areas adjoining the scrub, as well as the shadier areas occupied by scrub.

The Peacock, a species distributed throughout Ireland, uses the Stinging Nettle Urtica dioica as a foodplant, and it selects unshaded nettles growing close to scrub or woodland. It is possible that the scrub provides the warmth and shelter required for larval development. Fully fed larvae leave nettles to pupate on trees and scrub.

Speckled Wood, another widespread species, has a complex relationship with scrub. Known as a butterfly of hedges, scrub and woodland, it is our most shade-tolerant butterfly. The adult uses scrub for food (feeding on flowers such as bramble and Common Ivy Hedera helix, on ripe blackberries and aphid ‘honeydew’), for shelter from the rain and heat, resting and roosting, territorial perches, patrolling areas, mating stations, and dispersal routes. The butterfly breeds on native grasses growing at the edge of scrub, hedges, and woodland, but a seasonal difference exists in the egg-laying sites chosen. Early and late in the year, warm clumps of grasses in full sun are selected for oviposition, while during the summer heat, partly shaded lusher grasses in humid locations are selected. However, a female will adjust her choice of egg site according to temperature, so that grasses in shaded positions will be selected during hot weather in autumn.

Four butterfly species that breed on shrubs, Brimstone, Brown Hairstreak, Purple Hairstreak, and Holly Blue, use foodplants that receive direct sunlight. While often regarded as woodland species, none of these can breed within shaded areas of woodland or scrub. In the Burren, the eggs of the Brown Hairstreak are found on young growth on Common Blackthorn plants at the edge of a hedge,  scrub patch or woodland edge that is unshaded and south-facing.

Some butterflies enter a prolonged rest phase in their adult state. Four of our butterfly species undergo reproductive diapause in summer; these feed to build fat reserves before entering dormancy (quiescence) until the following spring when conditions favour breeding. The Brimstone, Small Tortoiseshell, Peacock, and Comma pass the winter in cool, dry conditions in scrub and woodland. It is likely that the Small Tortoiseshell, Peacock, and Comma require dense scrub for over-wintering. For this part of their life cycle, scrub and woodland habitats are vital.

The removal of large areas of scrub over an extended area can produce severe survival challenges for rarer, scrub-dependent butterflies. Any remaining areas may be too small to support populations. Where suitable habitat patches are isolated, a species may modify its behaviour to secure its survival. There may be selection for sedentary individuals. Highly localised, sedentary populations are vulnerable to extinction arising from causes such as habitat destruction, bad weather, parasitoids, or perhaps inbreeding. Selection for more sedentary races of the Pearl-bordered Fritillary is suspected to have taken place in England in areas where the butterfly depended largely or fully on coppicing for its habitat (Thomas and Lewington 2014).

Climate change is expected to produce warmer, drier summers in Ireland. Many of the warmest years on record have occurred since 2000. According to the Copernicus European State of the Climate report in 2020, 11 of the 12 warmest years occurred since 2000. The projected decreases in rainfall for Ireland are largest for summer, with reductions ranging from 0% to 13% and from 3% to 20% for the medium-to-low and high emission scenarios, respectively. Projections indicate an increase of 1–1.6°C in mean annual temperatures, with the largest increases seen in the east of the country. Warming is enhanced for the extremes (i.e., hot or cold days), with the highest daytime temperatures projected to rise by 0.7–2.6°C in summer and the lowest night-time temperatures to rise by 1.1–3°C in winter (Nolan 2015).

During recent hot, dry summers such as in 2018, desiccation of larval foodplants was observed in open, unshaded grasslands. During the hot weather, some species that usually frequent open areas during the day were observed sheltering in scrub. Interestingly, the Common Blue, which breeds on plants such as Common Bird’s-foot-trefoil growing in open grassland, was observed laying eggs on the foodplant growing in the shade. There may be several reasons for this untypical behaviour; the plants in open areas were in poor condition while in shaded areas they were not shriveled, the plants in shaded places were probably growing at the correct temperature during the heat of that summer, while during a more ‘typical’ summer, shaded plants will not support the larva. Finally, stress from extreme heat may be driving the adults to choose plants in less suitable micro-sites.

Breeding on plants shaded by scrub may be an adaptive behaviour by open grassland breeders under a warming climate. The increasing heat and dryness over the coming years may increase the importance of scrub for some Lepidoptera and other invertebrates.

The vast majority of Irish Lepidoptera are moths. There are about 1567 moth species recorded in Ireland with about 970 of these occurring in the Burren (D. Allen pers.com.). About 600 macro (larger) moths have been recorded. The following figures show the foodplants used by macro-moths; note that some species are polyphagous and use several of the following scrub species. 121 species have been recorded on willows, 96 species recorded on birches Betula spp., 61 species recorded on oaks Quercus spp., (the latter two tree groups are uncommon in the Burren scrublands), 26 species recorded on Aspen, 29 species recorded on Common Blackthorn, 36 species recorded on Common Hawthorn, 44 species recorded on Common Hazel, six species recorded on Purging Buckthorn and five on Alder Buckthorn (Waring et al 2004).

Hedges, scrub, and woodland are vital for our moth species, and not simply for larval foodplants. Moths use wooded habitats in similar ways to butterflies. One example is provided in a study by Coulthard et al. (2016) which showed that hedges are very important flight paths for moths. 68% of moths in the study were observed at 1m from the hedge, and of these 69% were moving parallel to the hedge. Hedges are believed to provide the sheltered corridors needed by flying insects in our generally open, farmed landscapes. This is likely to be especially relevant in open, exposed areas like the Burren.

There is an overwhelming body of evidence that supports the idea that more heterogeneous habitats can support more species diversity (Broeker 2018). Habitat heterogeneity, or small-scale changes in resource composition and structural complexity, provides more possible niche space for organisms to occupy and exploit (Tews et al, 2004). The range of habitats in the Burren, especially in the eastern areas, where complex mosaics of fens, cutover bogs, grasslands, heaths, limestone pavement, woods, and scrub exist support more butterfly species than anywhere else in Ireland. The scale of the habitats supports connectivity/dispersal, and genetic diversity and provides a range of niches in the face of the impacts of climate change, offering the prospect of adaptation when species are confronted with survival challenges. Maintenance of these conditions not only supports biodiversity generally, it preserves the magnificence of the region, touching those who experience the Burren with “the joy of elevated thoughts” (Lines Composed a Few Miles above Tintern Abbey, On Revisiting the Banks of the Wye during a Tour. July 13, 1798).

References

Broeker, H. (2018) Habitat Heterogeneity, Morphospecies Richness, and Niche Exploitation in the Human Skin Microbiome. Online at https://www.lakeforest.edu/news/habitat-heterogeneity-morphospecies-richness-and-niche-exploitation-in-the-human-skin-microbiome, accessed 11 September 2022

Coulthard, E., McCollin, D. & Littlemore, J. (2016) “The use of hedgerows as flight paths by moths in intensive farmland landscapes”, Journal of Insect Conservation, vol. 20, no. 2, pp. 345-350.

European Commission (2020) Warming trend shows 11 of the 12 warmest years occurred since 2000, according to the Copernicus European State of the Climate report. Online at: https://climate.copernicus.eu/warming-trend-shows-11-12-warmest-years-occurred-2000-according-copernicus-european-state-climate, accessed 10 September 2022

Fossitt, J.A. & Heritage Council Ireland (2000) A guide to habitats in Ireland. Heritage Council/Chomhairle Oidhreachta, Kilkenny.

Harding, J. (2021) The Irish Butterfly Book. Privately Published, Maynooth.

Nash, D., Boyd, T. & Hardiman, D. (2012) Ireland’s Butterflies: A Review. Dublin Naturalists’ Field Club, Dublin.

Nolan, P. 2015. EPA Report: Ensemble of Regional Climate Model Projections for Ireland. EPA climate change research report no. 159. EPA: Wexford. (show me this citation)

Tews, J., Brose, U., Grimm, V., Tielbörger, K., Wichmann, M. C., Schwa­ger, M., & Jeltsch, F. (2004) “Animal species diversity driven by habitat heterogeneity/diversity: the importance of keystone structures.” Journal of Biogeography, 31(1), 79-92.

Thomas, J. & Lewington, R. (2014) The Butterflies of Britain and Ireland. (Revised edition) British Wildlife Publishing, Dorset.

Waring, P., Townsend, M., & Lewington, R. (2004) Field Guide to the Moths of Great Britain and Ireland. British Wildlife Publishing, Hampshire.

 

 

 

 

 

In late summer and early autumn, we still have a large number of species flying.  A good, ‘natural’ garden stocked with native herbs and trees can attract all of the species featured below. Here is a selection of these butterflies and moths. All but one of the moths shown are strictly nocturnal and spend the daylight hours concealed among the leaves of trees and shrubs.

All photos J. Harding