Butterfly Conservation Ireland

This week the EU’s climate service Copernicus published figures for 2023. The headline statistic is that the temperature rise recorded last year, for a year, was the highest they had ever seen on record. But are we getting as full a picture as we should be?

Global surface air temperature highlights arising from the Copernicus data: 

• 2023 is confirmed as the warmest calendar year in global temperature data records going back to 1850.
• 2023 had a global average temperature of 14.98°C, 0.17°C higher than the previous highest annual value in 2016.
• 2023 was 0.60°C warmer than the 1991-2020 average and 1.48°C warmer than the 1850-1900 pre-industrial level.
• It is likely that a 12-month period ending in January or February 2024 will exceed 1.5°C above the pre-industrial level.
• 2023 marks the first time on record that every day within a year has exceeded 1°C above the 1850-1900 pre-industrial level. Close to 50% of days were more than 1.5°C warmer than the 1850-1900 level, and two days in November were, for the first time, more than 2°C warmer.
• Annual average air temperatures were the warmest on record, or close to the warmest, over sizeable parts of all ocean basins and all continents except Australia.
• Each month from June to December in 2023 was warmer than the corresponding month in any previous year.
• July and August 2023 were the warmest two months on record. Boreal summer (June-August) was also the warmest season on record.
• September 2023 was the month with a temperature deviation above the 1991–2020 average larger than any month in the ERA5 dataset.
• December 2023 was the warmest December on record globally, with an average temperature of 13.51°C, 0.85°C above the 1991-2020 average and 1.78°C above the 1850-1900 level for the month.

However, we need to consider the longer term to obtain a fuller picture of the recent history of our climate. By ‘recent history’ I mean the period since the last time Ireland, Britain, and much of northern Europe were dominated by ice 13,000 years ago. Sudden, dramatic changes have occurred during the past 13,000 years; sudden climate change is not new. 13,000 years ago all butterflies and likely most if not all of the other invertebrates would have been eliminated from Britain, Ireland and probably much of northern Europe.

Rapid warming occurred in the period up to c.11500 BC, with steadier warming thereafter: by 9000 BC, major ice sheets had been eroded significantly, though were (possibly) still in evidence in the highlands of modern-day northern Britain. As regards conditions over southern Britain, by c.11500 BC, it is estimated that mean winter-time temperatures were between 0 and 4°C (perhaps a little lower than today’s values) and high-summer values between 12 and 16°C, again a little lower or like current figures.

However, ice receded, but with the return of cold weather, over the following three thousand years. The severe downturn known as the ‘Younger Dryas’ reversal is thought to have started abruptly c.10,900 BC, reaching a depth of cold c.10,500 BC, when average temperatures are thought to have been mid-winter, -16 to -20°C (at least 15 °C below modern values – a truly dramatic fall) and high-summer, 8 to 12°C, about 4°C below modern values. This would have been disastrous – given the c.50yr period over which the decline is thought to have occurred: if it were to happen today, it has been argued that civilisation as we know it would cease. By 11,500 BC, most of these islands were ice-free. Butterflies and other invertebrates probably re-occupied these islands from about 10,000 BC. By 9500 BC, temperatures were back to pre-reversal levels. By 8400 BC the estimated temperatures were: mid-winter 0 to 4°C (like today) and high-summer 14 to 18°C. These figures represent a rapid increase, far larger and more sudden than is being reported by Copernicus since 1850.

According to the figures from Met Eireann, the seasonal mean temperatures for Ireland for 1991-2020 gives summer as the warmest season with a mean air temperature for Ireland of 14.6°C. Autumn is the second warmest season with a mean air temperature of 10.3°C, followed by Spring at 8.8°C. Winter is the coldest season with a mean air temperature of 5.4°C.

As you can see, even under a climate warming scenario, Ireland’s summer temperatures were up to 1.4 °C warmer in 8400 BC. In 5000 BC the mean temperature is estimated to have been 2 Celsius warmer than values in the second half of the twentieth century.

Around 3000 BC, the climatic limit of elm and lime trees moved northwards, and woods probably grew on Orkney and exposed areas in northern Scotland, suggesting less windy conditions than exist today.

However, around 2200 BC colder conditions returned probably arising from volcanic activity. Over time, mean temperatures fell and rainfall increased, and bogs developed. By 200 BC temperatures may have 2°C below those of the warmest post-glacial period.

(The source of this data is Weatherweb.net, the internet presence of Weather Consultancy Services Ltd (WCS). Established in 1997 WCS provides weather forecasts, climatological data and expert analysis worldwide, to customers ranging from farmers to multi-national PLCs. It contains information similar to that found in other specialist sources online.)

Estimates for climate change before weather recording began are derived from sources such as tree-ring dating, ice-cores, palynology (study of plant pollen, spores and certain microscopic plankton organisms (collectively termed palynomorphs) in both living and fossil form), population movements, settlement patterns, written sources after 3400 BC, etc.

According to Thomas (2014) between 8000 BC and roughly 3000 to 2000 BC average summer temperatures were 2-3 °C warmer than today but about 2500 BC the climate cooled by 2°C or more. This must have caused butterfly extinctions. The species sensitive to cold could only survive by finding unusually warm habitats, like those created by humans who were felling woods from c.5000 BC (from c.3000 BC in the Burren, interpreting the pollen record (D’Arcy 1992)).

Species like Gatekeeper  Pyronia tithonus probably became confined to the south coast of Ireland, in rocky areas which heated adjoining vegetation when the sun shone. Graylings Hipparchia semele would be likely to have retreated to areas devoid of tree cover where rocky and sandy habitats provided the heat-generating conditions they needed to grow their larvae. Other butterflies, like the Marsh Fritillary Euphydryas aurinia, are likely to have retreated to similar habitats and sheltered south-facing grasslands and large, sun-filled forest clearings.

In England, butterflies like the Silver-spotted Skipper Hesperia comma relied on areas cleared by humans and heavily grazed, where the grass was so short that soils baked in the summer sun. Woodland butterflies would have become dependent on coppiced woodland or areas in woods that were burned and allowed to recover.

In the 1970s and early 1980s, the Silver-spotted Skipper had reached a nadir, found on just 20 or so downland sites in southern England. Anyone who recalls the weather during the period 1977-1982 will remember wet, cold summers. The Silver-spotted Skipper needs warmer conditions than any other butterfly in Britain, and by the early 1980s, it looked destined for extinction in Britain. Studies were organised to assess its biology and habitat needs to attempt its conservation. It can very extremely difficult, and expensive, to restore a lost species.

The studies confirmed the climate and habitat constraints the species labours under in Britain. Female Silver-spotted Skippers strongly preferred Sheep’s-fescue  Festuca ovina plants (a grass species) that were growing well but were no more than 2.5cm in diameter and with about three-quarters of their edges adjoining bare ground. The females were avoiding tussocks under 1cm that have their tips eaten (typically by sheep and rabbits). Therefore, the butterfly wanted a thin-soiled, south-facing southern downland with 40% bare ground, 45% coverage of small Sheep’s-fescue plants, and the remaining 15% occupied by nectar sources. The fussiness meant that the butterfly needed a rather bespoke solution of heavy sheep grazing outside July and August, with no grazing during these months and the recovery of the rabbit population after it was struck by myxomatosis. Sheep grazing was restored to the steep south-facing chalk downs, rabbit populations recovered and today there are over 250 colonies in England (Thomas 2014).

Another plus supporting the butterfly’s recovery is the increasing summer temperatures from the 1990s. Because the temperatures have risen, the butterfly has become less reliant on heavy grazing, with the species now using plants with as little as 20% of their edges abutting bare ground and less reliant on strongly south-facing sites (Thomas 2014). I noticed a considerable change in the sward at the Silver-spotted Skipper’s breeding site on Box Hill, Surrey, which I first saw in 1995 and again in 2018. The butterfly was just as numerous in both years, but in 2018 the sward was taller and had far less bare soil than in 1995. There were sheep present in 1995 and not in 2018. The warmer summers have helped. Between 1979 and 2019, the Silver-spotted Skipper abundance rose by 596% (Fox et al. 2023).

A warming climate certainly does not suit all our butterflies and has been implicated, in combination with nitrogen pollution, in the decline of species such as the Wall Lasiommata megera. But it would be dishonest to claim that it represents a disaster for all biodiversity. The expanding Comma Polygonia c-album, Brown Argus Aricia agestis, and Holly Blue  Celastrina argiolus populations, among others, indicate that this is not the case. More research like that carried out into the biology and habitat requirements of the Silver-spotted Skipper is needed, because whether we agree with the way the climate data is presented, or the time scale used, climate change appears set to continue.

Accordingly, its effects on biodiversity must be assessed to shape policy and practice concerning our species and landscapes with particular emphasis on landscape-scale conservation to ensure a range of niches exist to mitigate climate impacts for species sensitive to changes in temperature and precipitation. Currently, climate change on its own is not an extinction risk to Ireland’s butterflies. The great damage being done today arises from habitat loss and changes to habitats arising from the intensification of farming. If climate change does threaten butterfly populations, it will likely do this in combination with pollution from agriculture and industry, and for some species, especially grass-feeders, this might be devastating.

References

D’Arcy, G. (1992) The Natural History of the Burren Immel Publishing, London.

Copernicus: 2023 is the hottest year on record, with global temperatures close to the 1.5 °C limit https://climate.copernicus.eu/copernicus-2023-hottest-year-record accessed 10 January 2024

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.

Ireland’s 30-year Climate Averages https://www.met.ie/cms/assets/uploads/2023/09/Irelands-Climate-Averages_1991-2020.pdf accessed 10 January 2024

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

WEATHER IN HISTORY 11,000 TO 4000BC https://premium.weatherweb.net/weather-in-history-11000-to-4000bc/ accessed 10 January 2024

WEATHER IN HISTORY 4000 TO 100BC https://premium.weatherweb.net/weather-in-history-400-to-100bc/ accessed 10 January 2024

All photographs copyright J. Harding

 

 

 

 

The short, dark days draw in so swiftly as 2023 hastens to a close. With Christmas to break the winter gloom, cheer is welcome, but the butterfly lover mourns the loss of colour and character that butterflies bring to life. Butterflies animate our world in ways no other creatures do. Their affinity with flowers creates multiple vistas of beauty and the irresistible power to fire imagination. Added to this palette is their link with bright sunshine that draws out colour, texture and form in ways nothing can, and perfection and happiness are defined. If this is not enough, our collective anxiety for the future of our Earth fixes attention strongly on the progress of butterflies. Butterflies are short-lived, respond rapidly to change and have life cycles that require different aspects of an ecosystem, are readily recordable so their population status offer an excellent barometer for environmental conditions. The decline and disappearance of the more sensitive butterflies sounds a silent alarm, like the canary who stops singing in a coal mine.

Winter in this part of the world is synonymised with death. The shadows deepen, sunshine is rationed, light at a premium, and clear only in cloudless skies. Our ancestors knew it too. At Newgrange they shared a part of their story about light with us, leaving behind a 62-foot-long passage terminating in a chamber flooded with light at the winter solstice.

But winter light does not necessarily bring comfort. It is sharp, piercing, and slanted, described in searing perfection by Emily Dickinson in her mood poem, There’s a certain Slant of light:

There’s a certain Slant of light,

Winter Afternoons –

That oppresses, like the Heft

Of Cathedral Tunes –

In the final stanza, the poet captures the universalised fear of winter’s cold, melancholy, unwarming, spiritually destructive light:

When it comes, the Landscape listens –

Shadows – hold their breath –

When it goes, ’tis like the Distance

On the look of Death –

The road we have left to travel is made clear by Dickinson.

The bleakness of winter drives many indoors, seeking the solace of the stove and central heating. However excessive indoor living is not healthy. Fleeing from the dying of the light, my past habits involved giving up on life until warmth returned in late March. But as my mental well-being discovered, that won’t do!

How does a lover of sunshine-dependent nature survive the winter? Applying a poetic licence, it is tempting to believe that winter kills all our butterflies. And there is certainly a foundation in science for this fallacy. Some adult butterflies, like the adorable Red Admiral pictured below, flee south to escape winter but most of our butterflies die off before winter’s shadows are even cast across the landscape. A few hardy species, four in total, hunker down to out-wait winter. Three of these (Brimstone, Peacock and Comma) are invisible to us. The part-exception is the Small Tortoiseshell, because it has a habit of entering occupied houses, among other sites, to seek overwintering accommodation. Thirteen Small Tortoiseshells in two plastic boxes lined with kitchen roll are residing in my fridge after the central heating woke them up. They have settled, all are alive, and will be released next spring.

But what happens to the Small Tortoiseshell, Comma and Peacock during the winter in the wild?

All three overwinter with closed wings, choosing cool, dry, dark places to pass several months of cold weather. How well does this work?

All three have subtle underside colouring, all three usually settle in places that are dark and that allow their colours to blend with their surroundings. Not being seen in the first place is the first line of defence against the attention of hungry, insectivorous birds, especially Robins, Wrens, Blue Tits, and Great Tits. All three of these butterflies overwinter in woods and dense scrub, while Peacocks and Small Tortoiseshells will also use caves, disused buildings, and partly submerged pipes.  A study conducted in Sweden (Vallin et al., 2005) compared the impact on all three species of Blue Tits. In the experiment, caged Commas, Peacocks, and Small Tortoiseshells were settled, so only the underwings were visible. The temperature was kept low to replicate winter conditions and encourage stillness in the butterflies. To have the chance to remain invisible, it is vital to remain immobile. Blue Tits were admitted to the cage for 40 minutes.

All the Peacocks and most of the Small Tortoiseshells (nine out of 15) flicked their wings open when the birds approached. The Peacock did this at a further distance from the birds than the Small Tortoiseshell. A sudden blaze of colour, the sound generated and perhaps the unexpected increase in size scared the birds. Every Peacock survived. The Peacock wing flashing, which is accompanied by a disconcerting hissing sound caused by friction generated during wing opening, caused the Blue Tits to flee. The wing flicking by discovered Small Tortoiseshells was not very effective. Overall, only 20% of Small Tortoiseshells survived, and only one discovered Small Tortoiseshell survived. In short, the Small Tortoiseshell is, it seems, heavily reliant on remaining unfound for survival. The Commas did not flick their wings open at any point, remaining still even if attacked. Overall, 67% of Commas survived.

The Peacock was the most discoverable but proved more intimidating than the Small Tortoiseshell, which was better hidden, followed by the Comma which was found least often and made no attempt to intimidate. All three are edible to birds, so none of them rely on chemical defences to deter the Blue Tits.

One might wonder why Small Tortoiseshells flick their wings open given it proved mostly unsuccessful in scaring the Blue Tits. It should be noted that the butterfly only flicked its wings open when the bird was very close, and it is likely that it ‘knew’ it had been discovered and had to fall onto a new line of defence. While wing flicking did not prove very effective in this case, it might be more effective against other birds and other predators.

Peacocks have been found overwintering together, in large groups. Given its ability to intimidate, overwintering in numbers makes sense; if a single Peacock can scare a Blue Tit, how intimidating is the combined impact of several flashing, hissing creatures?

The other Irish butterfly that passes the colder months as an adult but was not included in the study is the Brimstone. It uses different overwintering quarters to the three members of the Nymphalid family, selecting greenery to blend with its leaf-like appearance. Brimstones overwinter in clumps of ivy, under bramble leaves where bramble grows among other scrub and open woodland and probably in dense holly, yew, and Greater Tussock Sedge Carex paniculata. When a sleeping Brimstone is approached, it does not flick its wings open and remains immobile, even when handled. It likely relies, like the Comma, on being undiscovered.

What can one do to continue to enjoy butterflies in the off-season? One way is to read journals, books and new research, especially involving our native butterflies. Another way is to plan our butterfly gardens for the coming season. Another is to study butterflies that remain active during the colder months, not as adult butterflies, but in the caterpillar stage.

Rearing butterflies is a great way to do this. There is much that can be learned from rearing butterflies outdoors, in the open, to reproduce natural conditions as much as possible.

Currently, I am rearing Speckled Wood caterpillars. The caterpillars arose from eggs I obtained from two females I caught on 2 September. After laying several eggs, the butterflies were released. The eggs hatched just before mid-September, all within about two days.

The Speckled Wood caterpillar undergoes four instars (growth stages). Each instar ends when the caterpillar sheds its skin and enters the next instar or pupates after reaching full size at the end of the final instar. My Speckled Wood caterpillars are showing different growth rates, despite arising from eggs laid at the same time, hatching at almost the same time, and feeding on the same plants. Some of the caterpillars are in the third instar, others are in the fourth instar (this is the final instar before pupation), but none of these fourth instar caterpillars are fully grown.

The Speckled Wood butterfly is unique among Irish and British butterflies in being able to overwinter as a larva or pupa (Speckled Woods I reared from eggs that hatched in late July have reached the pupa stage). However, the available research, from caterpillars observed in Britain, shows that the Speckled Wood larva can only survive the onset of cold weather in the third instar.

If this holds for Irish Speckled Woods, my fourth instar caterpillars have a problem. Their only chance to survive is to complete their development and pupate before the cold weather strikes and feeding and digestion become impossible. They were still busy feeding today (10 December 2023), and they certainly need to continue, because these currently measure 20mm, and need to reach about 30mm before they are fully-fed. I suspect that nocturnal feeding occurs even in December, with caterpillars being found high on the foodplant beside recently nibbled grass. If these are in a race against time, they are taking full advantage of the milder nights with the night-time temperature of nine Celsius at 19:00 on 10 December.

Will they make it? How will this play out? Will I discover that the fourth instar Speckled Wood caterpillar can withstand the generally mild Irish winter? Is it more flexible than was thought? Butterflies and the natural world generally can keep us immersed year-round if we continue to engage!

Key Reference

Vallin, A., Jakobsson, S., Lind, J. & Wiklund, C. 2006, “Crypsis versus intimidation–anti-predation defence in three closely related butterflies”, Behavioral ecology and sociobiology, vol. 59, no. 3, pp. 455-459.

 

Sunshine, companionship, and conservation combined at Butterfly Conservation Ireland’s reserve at Lullybeg on Saturday 11 November.

We have endured torrential rain at the reserve and in Ireland in 2023. In March, April, July, August, September, and October the country had above-average rainfall, with July being the wettest month on record at 12 weather stations. November has been wet so far, but not on Saturday. Much of the northern section of the reserve has benefited from recent cattle grazing, and we plan to resume the grazing next spring, because the cattle still have work to do, with a very dense sward resulting from the year’s rain.

Our own remit on Saturday was simple: uproot as many saplings as we could in a section of flower-rich grassland. We worked in a line, uprooting as systematically as we could. Uprooting birch and willow is far better than strimming the vegetation. Strimming means you cut plants you don’t intend to target, and the saplings re-grow. Uprooting means saplings do not return.

Some denser areas of taller scrub need strimming, but our uprooting work involved plants c.30cm or less in height.

Another benefit of working close together is the catch-up chats, which is always a great feature of our work parties.

Working without machinery means you hear more: that screeching Jay, the short, clipped call of the Great-spotted Woodpecker, and the chip-chip call of the flock of around 30 Crossbills, flying high among the plantation Lodgepole Pines.

Our work was punctuated by lunch in the sunshine, a restful experience after a busy year on the reserve. We also unveiled our reserve information board, to some merriment and delight.

We know the wildlife on the reserve benefits from the work we do; that is the payoff!

Thanks to everyone who worked hard yesterday, and to all our supporters.

Photographs J. Harding

 

 

It is great to have some positive news to report. Butterfly Conservation Ireland’s reserve at Lullybeg has benefitted from a generous grant provided by Kildare County Council and the Department of Housing, Local Government and Heritage (NPWS). This article describes the reserve and explains how the grant has been applied to fulfil our conservation objectives.

Lullybeg Nature Reserve is a Bord na Móna rehabilitated cutaway, managed since 2010 by Butterfly Conservation Ireland (BCI). It is listed in the Bord na Móna Biodiversity Action Plan 2016-2021. It is described as a site of national importance in the Kildare County Development Plan 2023-2029. The reserve contains a butterfly transect walked up to 26 times each year between 1 April and 30 September. The records for the transect have been sent to the National Biodiversity Data Centre each year from 2008-2023. A report concerning the transect is published on the BCI website annually as part of the Annual Report.  Lullybeg Reserve is bounded by plantation forestry to the north and east and bare peat to the south and west. It lies on both sides of a waterway that is part of the Crabtree River.

The site contains several habitats existing as complex mosaics. Habitats found on the reserve include tall herb swamps, ponds, marsh, wet grassland, dry-humid acid grassland, dry calcareous and neutral grassland, wet heath, poor fen and flush, scrub and bog woodland. This is an important conservation location (rated Nationally Important) as it is home to a population of Marsh Fritillary Euphydryas aurinia, the only protected species of butterfly in Ireland (protected under Annex II of the Habitats’ Directive 1992). Other important butterflies present are Dark Green Fritillary Speyeria aglaja (ranked Vulnerable), Wall Brown (ranked Endangered) and Small Heath Coenonympha pamphilus (ranked Near Threatened). Twenty-six butterfly species have been recorded on the reserve.

The rewards of conservation management and scrub removal/control are evident as the already impressive list of flora and fauna recorded on site is increasing. As stated earlier, the site is used as a transect for the Irish Butterfly Monitoring Scheme (IBMS) run by the National Biodiversity Data Centre, with 15 years of IBMS records underlining the site’s importance for Lepidoptera.

Moths that are present on the site include species ranked Near Threatened on the macro-moth Red List published by the National Parks and Wildlife Service in 2016 (Allen et al. 2016), such as Small Chocolate-tip Clostera pigra, Dark Tussock Dicallomera fascelina, Small Purple-barred Phytometra viridaria, and species ranked as Vulnerable, such as Narrow-bordered Five-spot Burnet Zygaena lonicerae. Birds such as Teal (Amber-listed), Woodcock (Red-listed), and Snipe are among the breeding birds present. Merlin (Amber-listed), Buzzard, Kestrel (Red-listed), Sparrowhawk, Jay, Raven, and Linnet (Amber-listed) occur here.

The conservation work required consists mainly of scrub control and cattle grazing. Scrub must be controlled to maintain plagio-climax vegetation of flower-rich grassland, wet heath and fen with low scattered scrub over much of the eastern half of the reserve. The work of scrub control is labour-intensive and is done by hand and using power tools. Grazing is a vital conservation tool for maintaining grasslands for butterflies, moths and other invertebrates. A range of sward heights and periodic substrate disturbance is vital for habitat maintenance. To contain the livestock effectively, fixed and movable fencing is needed, as well as a safe, clean water source.

The National Parks and Wildlife Service is aware of the reserve and its importance. NPWS held a Marsh Fritillary survey methodology training day on the reserve, led by the state entomologist Dr. Brian Nelson. Butterfly Conservation Ireland’s Board of Directors includes Mr. Kieran Buckley recently District Conservation Officer for NPWS in County Kildare.

An annual report is written to describe the butterfly abundance trends on the reserve. These reports, titled Lullybeg Reserve Report, can be found under the Annual Reports tab on the Butterfly Conservation Ireland website. The most recent report, from 2022, can be found here:

https://butterflyconservation.ie/wp/report/butterfly-conservation-ireland-annual-report-2022/

Grant Expenditure

The grant aid, processed by Bridget Loughlin, the Heritage Officer in Kildare County Council was applied to the purchase of materials to manage the reserve. The fencing materials bought were conduction tape, fence posts, an electric battery, and a fencer. These were used to erect mobile fencing in the northeast section of the reserve in preparation for grazing by cattle.

In addition, fixed fencing containing gates were installed along the front of the reserve to ease access for visitors and to make delivery of livestock to the reserve more manageable. An information board was produced to introduce the reserve and acknowledge the support of Kildare County Council and the Department of Housing, Local Government and Heritage (NPWS).

The addition of the drinking trough and pump means the livestock have access to clean drinking water, making it more attractive to the farmer who provides the cattle to graze the site.

The power tools purchased, chain saws, pole saw, strimmer, and hedge trimmer will enable BCI to manage the reserve. The strimmer has been used to cut the vegetation under the fence to prevent it from interfering with the electric current. The chain saws have been used to clear an area of dense scrub to extend the grassland and reduce shading in an area that has the potential to host the Marsh Fritillary butterfly.

The pole saw and hedge trimmer will help BCI maintain the habitat by keeping developing scrub under control. These tools have a long reach making the dense scrub easier to tackle.

Safety equipment to operate the tools safely supports BCI’s volunteers.

Fencing is installed with gates to allow visitor access and is convenient for cattle delivery to the reserve. Photos 26 October 2023.

BCI expects the support provided to assist us in protecting this very important reserve. The latest data published in the Irish Butterfly Monitoring Scheme Newsletter by the National Biodiversity Data Centre concerning butterfly abundance is deeply concerning (Judge and Lysaght 2023).

Results from the multi-species index of the 15 most common butterfly species highlight that there was a moderate decline (-57%) in the population of butterflies in 2022 when compared to the baseline year of 2008.

It is important to note that the multi-species index is a useful index to show overall trends in population changes of common butterflies of the wider countryside. However, it does not generate sufficiently reliable data to track how the populations of our more localised or specialised butter-fly species are changing. This is because there is currently not enough data being recorded for these species. In order to capture adequate information on these species additional species-specific schemes (like the Marsh Fritillary Monitoring Scheme) are needed.

The Marsh Fritillary is monitored on the reserve and continues to thrive, but there are indications that it is declining elsewhere. The most recent government report to the EU Commission concerning the Marsh Fritillary indicates that it is not in favourable status.

Perhaps of greater importance is the decline of non-specialist butterflies. The 2023 Irish Butterfly Monitoring Scheme Newsletter reports a strong decline for the Ringlet and Meadow Brown, both thriving on the reserve. The decline of common species suggests a deeper, more widescale biodiversity loss.

It is hoped that the management of the reserve will continue to show the way to protect our countryside and species.

Finally, BCI would like to record its gratitude to Kildare County Council Heritage Officer, Bridget Loughlin for her help in processing the grant application, to the Kildare County Heritage Officer Maebh Boylan, and to Kildare County Council and the Department of Housing, Local Government and Heritage (NPWS) for the grant.

Key Reference

Judge, M and Lysaght, L. (2023). The Irish Butterfly Monitoring Scheme Newsletter, Issue 15. National Biodiversity Data Centre

 

October is the last month of the year to see butterflies in any numbers. What can be seen is even more crucially weather dependent, but this year’s October has seen some exceptionally warm weather, with some good abundance figures for the time of year.

We are seeing some unseasonable behaviour. On 14/10/2023 I observed a courtship flight by a Red Admiral pair, and it appeared destined to culminate in mating. The gentle fluttering flight used by both sexes is a sign of female cooperation in this butterfly, and if the pair remained in the lane instead of slipping quietly into an adjoining field, probably to seek shelter from the stiff north-west breeze, I feel sure that I would have observed their pairing.

I have never seen the Red Admiral behave like this in autumn in Ireland, so perhaps we are seeing the species beginning to stay put, even 33km inland, rather than migrating south, the situation that traditionally applies in Ireland. Since the turn of this century, coastal breeding in two areas (Howth, Dublin and Ravenwood, Wexford) during late autumn has been recorded, but not inland, where the colder conditions destroy the Common Nettle.

Painted Ladies were still being seen, inland and on the coast. Like their relatives, their main and probably only nectar source in many areas is our Common Ivy. While they remain, we are holding on to the memories of summer.

Another feature of change that has extended the pleasure of seeing butterflies deeper into autumn is the spread of the Comma, and its ability to produce a second generation in Ireland, a generation that hatches from the pupa in September and October.

This lovely addition to our butterfly fauna can be seen sunning its gleaming orange-red wings on shiny bramble and ivy leaves, feeding on their fruit and flowers respectively. After the feeding is complete, the Comma hides itself in dense wooded cover until spring’s rays warm it to action.

In some woods, a dozen or more will be found in March feeding on a flowering Grey Willow. Slightly later, dandelion comes on stream. By the time this occurs, the males are defending territories and seeking passing females.

What is much less visible is the activities of moth and butterfly caterpillars, many of them still busily feeding before colder weather pauses their activity. Autumn moths are still in flight, such as the Merveille du Jour pictured here. Last weekend I had 19 moth species in my garden trap, a good showing for October, but the night I trapped was very mild.

At this time of the year, sunny, sheltered south-facing hedges containing flowering ivy are the best places to look for butterfly life. In a week or so, even these places will hold little evidence of a fine summer for many of our butterflies, leaving us with our memories but also our hopes for next spring.

Photographs © J. Harding

Time, like an ever-rolling stream
bears all its sons away;
they fly forgotten, as a dream
dies at the op’ning day.

(O God Our Help in Ages Past, Isaac Watts, 1674-1748)

Since humans learned to manipulate the environment to produce food, the natural world has been changing. Some people try to help nature by trying to restore what once was. Conscious not just of nature’s fragility but also of our mortality, the desire to leave something good that will outlast us is a powerful motivation. The following article reviews, briefly, what we have lost, describes efforts to reintroduce lost butterflies, and assesses the validity of reintroductions.

Animal and plant population loss is a common theme across the world. Humans have been radically altering the natural environment for thousands of years, especially since the farming of plants and animals began during the Neolithic period about 12,000 years ago. Mesolithic man was a hunter-gatherer, who moved through the landscape, surviving on food he picked, dug and hunted. There were no permanent settlements, and in Ireland and in other places, he used waterways to reach new areas to find food. Plant and animal domestication made long-term and permanent settlements possible, and humans began to replace natural vegetation with crops and grazing for animals.

Animals that threatened domesticated animals were killed when this was possible, and humans learned to protect livestock using dogs, and walls and by removing habitat for predators. Determined attempts were made to extirpate predatory animals, with rewards offered for proof of kills. The environment we have inherited is quite different from before farming was used to feed people and build civilizations; the pollen records and archaeological evidence show evidence of radically altered ecosystems.

The Brown Bear, the Eurasian Wolf, Wild Boar and Giant Elk are long extinct from Ireland and Britain, with the Giant Elk lost from the world, a likely victim of overkill and perhaps natural climate change. Many habitats are at a fraction of their original extent, and no fully natural habitat exists in these islands and in most of Europe. What these looked like is very difficult to say; there is recent research that challenges the long-held view that woodland dominated our landscapes before humans dominated them. The widespread presence of open grassland invertebrates today suggests that large areas of natural grassland must have existed.

The pollen record is not an infallible guide; some plants produce far more than others and some plant pollen travels further. Scots Pine falls into these categories; we cannot deduce huge pine forests existed simply because its pollen is abundant in the archaeological record. The pollen record does indicate that grasslands existed along with woods.

A mixed landscape of wooded and more open areas is now believed to have existed before the onslaught on forested areas by humans. When we began reafforestation early in the 20th century, we decided to use fast-growing non-native coniferous trees which lack any relationship with the woods we once had, and this approach, recently modified in favour of including some native trees, has continued. The most severe recent habitat loss in this country following the loss of native woods and grassland is our raised bogs, mostly destroyed. I doubt there is a single raised bog in Ireland that is undamaged.

Animals and plants require suitable conditions for their survival. When a species is lost from an area, it is usually because important conditions it needs no longer exist on a sufficient scale. You cannot, for example, plough a field containing wild grasses and herbs and re-seed it with agricultural grasses and White Clover and expect all the original insects it supported to survive.

There are people who dream of landscapes filled with beauty, containing the species we know once existed more widely. We cherish the often-small areas that still hold these natural features and want them protected and restored. Restoration involves returning existing habitats to their best condition, usually through some form of direct management.

Some go further; rewilding is their goal. Rewilding is the restoration of an area of land to its (original) natural uncultivated state; the idea is to remove human influence. In pursuit of these dreams, some people want to return animals that once existed in our environments. This has happened in Ireland, with the state-funded projects to restore the extirpated Golden and White-tailed Sea Eagles and Red Kite. Eurasian Beavers were reintroduced to parts of England and Scotland, many unofficially. Beavers are sometimes admiringly referred to as “ecosystem engineers”. By damming streams, they reshape valley bottoms, creating new ponds and waterways that rapidly fill with birds, amphibians, dragonflies, and other insects and fish. Research also shows how dams filter polluted water, and store huge quantities of floodwater. Beavers’ dams can even prevent towns from being flooded. But the water must go somewhere – and the farmers whose fields are flooded as a result tend to detest these rodent engineers.

One animal group that might be less controversially reintroduced is Lepidoptera, butterflies and moths. Some are easy to breed and easy to introduce. Just to be clear, reintroduction is the intentional movement and release of a species within an area that was once part of its historical range, but from which it has become extinct.

This has occurred in well-organized ways in England, with the reintroduction of the Large Blue (wiped out in 1979) and Chequered Skipper (went extinct in 1977). These reintroductions were underpinned by painstaking research and habitat restoration; the stock for the reintroduction of the Large Blue was sourced from Sweden while the Chequered Skippers were taken in Belgium.

But these were professionally executed and scientifically informed. Some people, however, are impatient with the slow progress of official reintroduction programmes and have decided to do it themselves.

Martin White from Nottinghamshire was a rewilder passionate about the reintroduction of extinct butterflies. He bemoaned the slow pace and cost involved in official reintroductions. He said that his first attempt to reintroduce the Mazarine Blue cost him less than £10. Contrastingly, official programmes cost much more. Transporting the Chequered Skipper to Rockingham Forest, Northamptonshire (north of Milton Keynes) via Eurostar cost £10,000.

White has introduced thousands of butterflies to various places; many of these efforts failed. But some succeeded; he closed a 90-mile gap in the Marbled White’s distribution between the midlands and the Yorkshire Wolds. He reintroduced the Purple Emperor to Lincolnshire. He has introduced the Dingy Skipper onto former mine sites, with success. Some butterflies cannot reach suitable sites because the intervening countryside is so hostile to insects that seek to move. Migrating insects must brave herbicides, pesticides, foodless ground, and long distances to reach areas that have become suitable again. Unless you are a powerful species, like the Red Admiral, the chances of natural recolonisation are very low.

But will these efforts succeed over the longer term? If a butterfly or moth is missing from a site, there is reason for its absence. Unless dealt with, simply releasing fertilised females will not help, even if the larval foodplants still occur on the site. Some species have highly specific needs that extend far beyond the presence of their foodplant. What often seems to happen is that the released butterfly breeds for a year or two before dying out.

What annoys nature reserve managers is the clamour to ‘save’ a reintroduced butterfly that reached the reserve via the car boot. People want to see rarities, such as the Marsh Fritillary or Glanville Fritillary so insist on this one butterfly being accorded conservation priority. This can reach extreme levels of attention. The only known Marsh Fritillary colony in Lincolnshire (courtesy of Martin White) exists in two fields, 100 miles from the nearest colony. The caterpillars are collected by volunteers and replaced on their foodplant after the area is mown. This is certainly not natural, and one wonders what the argument is for artificially maintaining this population. This is a gardening exercise, not a conservation one.

What is perhaps a more serious concern is using butterflies sourced in Europe to reintroduce a butterfly to an area in Ireland or Britain when the species still occurs in these countries. For example, Purple Emperors sourced in Germany were used to re-populate woods in east England. This might be harmful to native populations of the butterfly if pests or pathogens arrive with them. It might also change the genetic makeup of native Purple Emperors, which may have developed the genome to cope with English conditions.

There is evidence that introduced or reintroduced butterflies might create difficulties for other butterfly species. The arrival of the Map butterfly in southern Sweden (which it reached unaided) coincided with increased rates of infection by parasites of two other nettle-feeding butterflies, the Small Tortoiseshell and Peacock.

The three species’ caterpillars overlap in their occurrence, but there are phenological differences (differences in the timing of the hatching of the caterpillars).

The Map might be causing higher infection rates by shared parasitoids by providing a host for the parasitoids when the larvae of the Small Tortoiseshell and Peacock are scarce.

Therefore, there are times in the year when Map larvae are plentiful but those of the Peacock and Small Tortoiseshell are less numerous. Phenological differences in the parasitoids between hosts might also mean the Map is assisting increased infection rates in its butterfly relatives. If correct, the Map is reducing the competition for its food (nettles) during its establishment phase, but if the Map recruits more parasitoids, as the Swedish study indicates is likely, a balance between these butterflies might be struck.

But the study did not look at the parasitoids that the Map may have introduced to the other three butterflies, only looking at shared parasitoids, and looked at larval parasitoids, not egg or pupal ones.

The relationships are therefore not well-known and extrapolation from the Swedish experience may not be possible in another area with different conditions. Therefore, harm might be caused to native populations by reintroducing a butterfly or moth; however, after establishment, a balance might develop as the new arrival becomes subject to biological controls.

This is where the need to investigate impacts arises. The most useful step is to protect existing habitats, restore them where needed and extend them so that populations can move through the landscape. Where large areas of suitable habitat exist whether this is mainly the result of long-term favourable management, restoration, rewilding, or natural processes, then the conditions for the reintroduction of animal or plant species might be reached. Given the state of our habitats, reintroduction might even be necessary.

The severe reduction in the area of the Small Blue’s habitat along the Dublin coastline due to serious coastal erosion, management problems and the creation of golf links prompted an introduction of the species in extensive suitable habitat in County Meath and Louth. This attempt has been very successful. Meanwhile, the donor population has lost about 90% of its original habitat, which has been swallowed by the sea. The remaining population is hanging by the proverbial thread.

If the dune habitat on the donor site is restored by natural or human action, the new populations might return the compliment! This has already happened in England. Black Hairstreak butterflies from Monk’s Wood, Cambridgeshire were used to establish a new population at Warboys Wood. When Monk’s Wood lost its population during the Great War, it was repopulated from its receptor site. The restored Monk’s Wood population still exists to this day!

Considerable resistance to unauthorised, unofficial reintroduction exists and has for some time. It is illegal to introduce an exotic animal into the wild in Ireland and illegal to introduce or reintroduce, without consent, any animal or plant not already present in certain protected areas after a Statutory Instrument has been signed. It is a great pity that this is not the case for non-native plants in the general countryside. Biological recorders resent their maps being compromised by records of unofficially released species. This makes it harder to calculate the true distribution of a species, especially given the often transient presence of introduced species. Others hate the idea, captured in naturalist  Robert Lloyd Praeger’s phrase of ‘forging nature’s signature’, by introducing species in areas where they might never have occurred.

There are very good reasons for not interfering with nature. There are very good reasons for interfering with nature. In the absence of good motives and good research, reintroduction should not be tried. Bad motives include removing rarities from a site because it is about to be destroyed by a development or introducing rarities to a site that is about to be destroyed by a development. Martin White carried out his introductions because he loved butterflies and wanted to leave a legacy, to feel that his life was not a waste. Martin White died on 12 October 2020. He knew his time was coming months before. He was still releasing butterflies in the summer of 2020. Whatever the ecological impacts of his efforts, it is touching to see his drive to see nature flourish.

The damage we have done places a moral obligation on us to atone. Reintroductions might be part of this process. It might be a question of how these are done, not whether they are done. But let’s focus chiefly on looking after our habitats and extending them. Without good, large-scale habitats, many species don’t stand a chance.

 

Key References

Audusseau, H., Ryrholm, N., Stefanescu, C., Tharel, S., Jansson, C., Champeaux, L., Shaw, M.R., Raper, C., Lewis, O.T., Janz, N. & Schmucki, R. 2021, “Rewiring of interactions in a changing environment: nettle‐feeding butterflies and their parasitoids”, Oikos, vol. 130, no. 4, pp. 624-636.

https://www.theguardian.com/environment/2020/oct/13/maverick-rewilders-endangered-species-extinction-conservation-uk-wildlife Accessed 01/10/2023

 

 

 

The extraordinary garden of Robert Donnelly and Jane Doughty boasts enormous butterfly populations, with hundreds of butterflies counted for Butterfly Conservation Ireland’s National Garden Butterfly Survey annually.  On just one day,  27 August 2020, 154 Small Tortoiseshells were counted, feasting on native flowers such as Hemp Agrimony Eupatorium cannabinum. Less frequent garden visitors, such as Cryptic Wood White, Small Copper, Comma, and Silver-washed Fritillary also make Robert and Jane’s garden at Little Eden in County Kilkenny their home.

But Little Eden is not just looking after local butterflies. The garden’s fruit and vegetable yield generated €793.42 from neighbours and passers-by, which Robert and Jane have kindly donated to Butterfly Conservation Ireland. Their help is timely, as we are currently arranging fencing for the front boundary of the reserve in Lullybeg in northwest Kildare to improve the security of the area to ensure grazing livestock needed to conserve the grassland habitats are better contained.

A great thanks to Robert and Jane for all they do for butterflies local and national. The joy of seeing beautiful butterflies in our gardens and beyond, like this Red Admiral, depends on the care for nature shown by Jane, Robert, and all our members and supporters.

Thank you.

 

Every year, up to this, I have been contacted by one media outlet or another to explain where our butterflies are and why aren’t we seeing them. The interviewer typically prefaces his or her question with, “When I was a child I saw plenty of butterflies, so why am I seeing so few today?”

This year, 2023, is the first year that I was not asked this question. On the contrary, people commented happily about finding large populations adorning gardens and elsewhere this summer (but not in spring) and taking delight at seeing so many. Are they right, or is this just an impression formed by seeing butterflies when people have time off, like during August? Butterfly abundance peaks do not occur at the same time every year, so the poor weather in July is likely to have pushed peaks into August when the weather improved, and people had time to notice.

Let’s leave the butterfly year of 2023 to the annual report we publish under the Report heading. The National Biodiversity Data Centre (NBDC) has published the Irish Butterfly Monitoring Scheme Newsletter for 2022, the warmest year on record. What do the findings tell us?

Firstly, just a quick word on how the information is obtained. The Irish Butterfly Monitoring Scheme (IBMS) involves walking a fixed route (transect) on a weekly basis from 1st April to 30th September each year when weather conditions are favourable. The number of the different butterfly species seen along different sections of each transect are recorded. These records are the basic data upon which the analysis is based. The IBMS  tracks population and phenology (time of flight) trends in Irish butterflies, detecting the impacts of factors such as land use and climate change on the Irish butterfly population.

A reduced effort transect scheme, the Five Visit Monitoring Scheme (FVMS) helps to capture abundance. (Several Butterfly Conservation Ireland (BCI) members are involved in these important schemes and BCI runs its own recording scheme which provides data on distribution).

The results in the 2022 report do not make for happy reading.

The multi-species index which estimates the overall direction of change in the butterfly population using Ireland’s most common resident butterflies (15 species) shows that once again there was a moderate decline (-57%) in the number of butterflies flying in 2022 when compared with the baseline year of 2008 (the start of the monitoring scheme). Only the Holly Blue Celastrina argiolus showed an increase in the last 10 years (+149%), with all other species showing uncertain, stable or moderately declining trends.

It is important to note that the multi-species index is a useful index to show overall trends in population changes of common butterflies of the wider countryside. However, it does not generate sufficiently reliable data to track how the populations of our more localised or specialised butterfly species are changing. This is because there is currently not enough data being recorded for these species. To capture adequate information on these species additional species-specific schemes (like the Marsh Fritillary Monitoring Scheme) are needed.

The greatest declines during the period 2008-2022 are the Green-veined White (-81%), followed by Meadow Brown Maniola jurtina (-74%), Ringlet Aphantopus hyperantus (-72%), Large White Pieris brassicae (-71%), and Small Heath Coenonympha pamphilus (-68%). Aside from the Small Heath which has lost the status of being a wider countryside butterfly, all of these are, which suggests that there are significant problems in our environment. These are widespread butterflies, which suggests a widescale environmental crisis. Butterfly abundance will rise and fall naturally from year to year, but these declines span 14 years and are persistent.

Without great changes to farming methods, this is unlikely to change. The causes are not provided by the IBMS data but we can see that our farmed landscape is doused with herbicide, pesticide and synthetic fertilisers. These damage vegetation and butterflies; there is scientific evidence for this, as well as the more subjective, anecdotal support derived from personal experience.

A damp grass field near my home supported common countryside butterflies such as Orange-tip Anthocharis cardamines, Green-veined White Artogeia napi, Cryptic Wood White Leptidea juvernica and the Small Copper. Intensification began to occur. The vegetation was topped early one year to tackle rushes Juncus spp. This did not impact the butterflies but this spring herbicide was applied. It completely removed Common Sorrel Rumex acetosa (Small Copper foodplant), Cuckooflower Cardamines pratensis (Orange-tip and Green-veined White foodplant) and most if not all vetches especially Meadow Vetchling Lathyrus pratensis (Cryptic Wood White). I observed none of these species in this field in 2023. Even when herbicide is not used, nitrates play havoc with many butterflies.

While the EU Nitrates Directive has cut organic nitrates that can be applied to 220kg of nitrate per hectare, this figure is above the safe physiological tolerance level of the larvae of the six butterfly and moth species (Small Copper, Sooty Copper Lycaena tityrus, Speckled Wood Pararge aegeria, Small Heath, Blood Vein Timandra comae and Straw Dot Rivula sericealis) studied by Susanne Kurze and her colleagues.

The Kurze study showed declines in the survival of all six species when fed on sorrels and grass (depending on the moth or butterfly) when their plants were given between 150 and 300 kg N ha−1 year−1. At the higher rate, the sorrels died. The survival rate of the Small Copper was nearly 50% lower in the group fed on N300 than those fed on unfertilised plants. Grass-feeding species also suffered. The survival rate in the Small Heath and Speckled Wood declined by one-third under both nitrogen treatments compared with unfertilised plants.  Interestingly, some Speckled Wood larvae survived to pupation but the Small Heath larvae that died did not live longer than 45 days or reach pupation. The most sensitive species was the Straw Dot. Its survival rate declined by half between the control and the N150 treatment and about 80% between the control and the N300 treatment.

This study only scratches the surface. It did not deal with the impacts of these fertiliser concentrations on the overall vegetation in the wild, or the effect of more vigorous plant growth on soil and above-ground temperatures, all of which can also be expected to influence survival rates.

There is a great need for sustainable farming. Stocking rates are absurdly high, maintainable only by massive fertiliser inputs which poison wildlife, pollute water and add to global warming gases.

There is certainly no excuse for continuing to kill off our planet’s most beautiful animals. We waste about one-third of our food, so we are grossly over-producing and over-consuming. Our butterflies don’t need it and nor do we.

Key References:

Judge, M and Lysaght, L. (2023). The Irish Butterfly Monitoring Scheme Newsletter, Issue 15. National Biodiversity Data Centre.

Kurze, S., Heinken, T. & Fartmann, T. 2018, “Nitrogen enrichment in host plants increases the mortality of common Lepidoptera species”, Oecologia, vol. 188, no. 4, pp. 1227-1237.

All photographs © J. Harding

After being drenched and underwhelmed by daytime maxima of 13°C  during July and August our early September sunshine and warmth is a serious restorative. Today we are looking at 22°C to 26°C; yesterday temperatures climbed above 27°C in some areas; that’s more like it!

Met Eireann tells us that July 2023 was “very wet, cool and dull.”  In fact, it was the wettest July on record. The highest temperature recorded in July was on one day, July 7th, and was 24.1 °C in Fanad, County Donegal. While August had better weather, it was not a classic summer month. Described as “mild and changeable” the temperatures were above average nearly everywhere but so was rainfall. Poor Newport in County Mayo had 29 wet days during August!

This doesn’t look like our butterflies should have had a good year, given what our ‘summer’ weather was like, and if I include June this was much better (warmest June on record at most weather stations, with average rainfall). Athenry, County Galway and Shannon Airport, County Clare experienced 27 consecutive days with maximum air temperatures > 20.0 °C, ending on Saturday 24 June. Some of our summer flying butterflies had a spectacular year, with some very high abundance reported to Butterfly Conservation Ireland.

On September 3rd, for example, 246 Small Tortoiseshells were reported from Lullymore, and hundreds of Small Whites and hundreds of Small Tortoiseshells were seen on a wildlife-friendly farm near Maynooth. Red Admirals and Commas are booming too, Green-veined Whites, which love moist, damp habitats, are up, and so are Meadow Brown and Ringlet populations. Holly Blue seems to be thriving and spreading. Early in August, I counted 91 Brimstones just in a small area in Lullybeg; there must have been hundreds of this highly localised butterfly in the bogland in northwest Kildare.

So what can we expect this month? Top of the list is the Small Tortoiseshell, which is everywhere now, even in the Sutton area in Dublin, where the butterfly has gone into a second brood for the first time in many years, thanks probably for July’s bountiful rain and the boost to Stinging Nettles.

The highest numbers of the year are present now but this abundance will be brief. While they are busy feeding, they gain weight and their flight is considerably slower, especially in the cooler temperatures expected as September advances. It is risky to stay on the wing for too long, as dragonflies and birds are eager predators of butterflies. In the past few days, Small Tortoiseshells have entered buildings to look for a secluded nook to pass the winter in. In fact, some will find a spot, retain a topographical memory of its location, and fly out to resume feeding, safe in the knowledge that they know where they will hunker down. Experiments carried out in England show that the Small Tortoiseshell relies on its memory to relocate important sites.

They do not always choose well. A centrally heated building will awaken them in autumn, and deceive the butterfly into the idea that spring is here. Capture and release is not the advised approach; capture and relocation in a cool place is the best policy. A plastic lidded box lined with absorbent kitchen roll in the bottom of the fridge is a good place; no air holes are needed. Release them in March when a warm spell, predicted to last a few days, arrives.

By contrast with the Small Tortoiseshell boom, Peacocks on the wing are few in number. Most are in hibernation and will stay put despite the blandishments of high September temperatures and nectar. This poor Peacock looks the way we might feel after a bad day. Remarkably, this butterfly flew away, albeit awkwardly, after the photo was taken. Staying out late is risky, as pointed out earlier!

Another butterfly that passes the winter in the adult stage, the Brimstone, is similarly out there in greatly reduced abundance. Most of them are concealed in evergreen foliage, blending with their leaflike wings to aid blending. We will see a few still feeding, and these are wisely very close to over-wintering cover.

Green-veined White butterflies really suffer from droughts, but not this year. Here is a male on Devil’s-bit Scabious, his forewings packed with citral (C10H16O), a pheromone used to seduce a female. It is a powerful, sweet fragrance, easily detected by a human, so it must be an all-enveloping experience for a female Green-veined White. This butterfly is still breeding and the species will pass the winter as a caterpillar.

And now for something different! The next two butterflies are migrants. Unlike our resident butterflies, these two are not cold-adapted species. Unlike our resident natives, these do not have a rest phase in their life cycle and are continuously brooded, which means they breed and grow throughout the year. In more technical language, they do not undergo a diapause phase. If a butterfly cannot delay breeding, it requires the correct conditions to reproduce throughout the year. These conditions are not currently available in most of northern Europe, so an escape strategy must be applied. Migration is a way to avoid the onset of unsuitable conditions. In spring and summer, the heat in North Africa and parts of Southern Europe drives some migrants north to find the conditions needed.

The Red Admiral is our most regular migrant butterfly. It occurs in Ireland from about March to November and they leave during the autumn months. When the herbaceous flowers are gone, it uses ivy nectar, sap runs and overripe fruit for sustenance. There are still Red Admiral larvae on nettles so we will see the adults for some weeks yet.

The lovely Clouded Yellow is a visitor too, but in smaller numbers and often later in the year, especially during September and October. In some years a mass arrival followed by breeding occurs. In these years, they arrive earlier, usually from April onward.

In years when they arrive later, the Clouded Yellow does attempt to breed, but it is likely that the attempts fail as the temperatures drop. But the butterfly is a delight to see whenever it appears. This female was seen in Lullymore by Pat Wyse and Fionnuala Parnell, enjoy!

Back to our resident butterflies, the Comma is beginning to hatch its second generation which flies during autumn. This makes it unique among our butterflies. We will say more about the Comma in our October post, but keep a close eye on ripe blackberries and ivy in the coming weeks.

The heatwave during the first week in September has coaxed migrants from southern Europe to journey north. This Vestal is one of four to visit a garden in County Meath on 7th September. The colour of this moth is strongly influenced by the temperature experienced by the pupa with bright specimens like this one the result of hotter conditions, suggesting that this one is from the Mediterranean area of Europe or North Africa. It is mainly a nocturnal moth but can be found on grass stalks during the day.

All photos by J. Harding except Clouded Yellow P. Wyse.

 

 

 

 

 

 

There is a drop in the number of moth species present in the garden in August compared with June and July but there is still variety in my moth trap, with some intriguing species. Here is a selection of moths that fly during August.

The Magpie is a striking moth that flies at night but occasionally during the day too. I recently watched a female flying on a sunny afternoon, laying eggs on Berberis thunbergii atropurpurea, a purple-leaved garden plant used for hedging or as an individual specimen. It breeds on a wide range of native plants Common Hazel, Common Hawthorn, Common Spindle, Heather (in Scotland and presumably here). It is capable of long flights, and famously Orkney and Shetland were colonized by it in the last few years. It appears to enjoy good abundance in Ireland but it has declined in England and Wales.

The Chinese Character might be better called the Bird Dropping moth for its resemblance to a bird dropping. This breeder on Crab Apple, Common Blackthorn, Common Hawthorn, Rowan, and other trees appears to be avoided by birds. Certainly, my Robin, who loves seeing my moth trap light up, shows no interest in this enigmatic moth. This moth is double-brooded.

The Scalloped Oak is also nocturnal and while it breeds on oak, it uses a wide range of trees as well as Honeysuckle, Bilberry and Heather. Given such a wide range of foodplants, it occurs in a range of habitats, such as woodland, hedges, gardens, parks, and bogs. It has one generation every year.

The Gold Spot is double-brooded, nocturnal, and occasionally day-flying when the day is muggy and overcast. It likes wet habitats, as it breeds on sedges, Yellow Iris, Branched Bur-reed and Water-plantain. It occurs in gardens that hold ponds with marsh and marginal vegetation.

The Pebble Prominent is generally common, breeds on willows and is double-brooded. In some years I get only one or two, but this year has been better, with five found last Wednesday.

The Bee moth is a very interesting micro-moth that breeds on the nests of a range of wasp and bee species. Their yellow caterpillars protect themselves from their hosts by spinning a tough silk case, while they feed on the comb, honey, stored food, and even meconium (fecal matter). They can destroy nests and are considered a pest by beekeepers. Both sexes use sex pheromones during courtship and males sing to females by vibrating their abdominal plates. A courtship dance by both sexes occurs before mating. While this appears to be a destructive species, it should be noted that all species have their enemies, and it is rarely if ever the case that one species destroys its host, under circumstances of a functional ecosystem.

The Canary-shouldered Thorn is very well-named! It breeds on Downy and Silver Birch, Alder, limes, elms, Goat Willow, and Hornbeam. It is strictly nocturnal and flies in just one generation a year, from July to mid-October.  It spends the daylight within trees, concealed on the underside of leaves.

As you can see, these moths breed mostly on native plants or, in the case of the Bee Moth feed on hosts that use native plants. By making native trees, shrubs, and flowers the key architecture of your garden, you will be making homes for our native moths and all the species that depend on moths for their survival. The Russian revolutionary Lenin is quoted as having said, “Everything is connected to everything else.” Without the elements needed, our ecosystems would collapse. Moths are excellent indicators of ecosystem functioning because they play such key roles mainly by providing food, pollination, and plant growth regulation. We have c. 1567 moth species in Ireland, so they are a significant proportion of our invertebrate population. Together with butterflies, the order Lepidoptera makes up about 9% of all life forms on the planet. We cannot do without them.