A beautiful sunny day on Sunday 14th October encouraged butterflies to enjoy the heat. A calm day allowed heat to build, enticing over-wintering butterflies to venture out. A male Brimstone, some Small Tortoiseshells and a Peacock brightened this mid-autumn day. These were joined by two female Small Coppers, a Red Admiral and a brace of Speckled Woods. Ruddy Darters dragonflies were everywhere, grasshoppers chirruped and it felt like August!
Leaving to go home was hard but a bright orange neon glow on glossy ivy leaves high up on a hedge at Lullymore stopped the car. A lovely Comma! Will it breed in the area? There is an abundance of breeding habitat and overwintering sites in the area. It was still there today (Monday, October 15th) and seems to be making itself comfortable sipping ivy nectar. Welcome to west Kildare!
The Comma butterfly was first sighted in Ireland in the late 1990s but it was not until about the second decade of this century that regular sightings were being reported. Breeding was first confirmed in a wood in Carlow in May 2014. Since then the butterfly has been reported, usually as single individuals, in many areas in the south-east. Its spread is expected to continue, and it joins the 23 other butterfly species recorded in Lullymore/Lullybeg in 2018.
For many lovers of nature, especially for those of us who enjoy butterflies, autumn is unwelcome. We see the signs of decline everywhere and we fear the season to follow. This is not a recent feeling. Sonnet 73, written by William Shakespeare sometime between 1592 and 1598, opens with this quatrain:
That time of year thou may’st in me behold
When yellow leaves, or none, or few, do hang
Upon those boughs which shake against the cold,
Bare ruin’d choirs, where late the sweet birds sang.
Shakespeare wrote about late autumn, which he associates with decay and imminent death. The trees with few or no leaves are now without birdsong. He may be referring to the by then ruined monastic settlements, the closure of which was ordered by Henry VIII following his decision to cut ties with the pope and confiscate church property (1536-1540). Seen in the light of this interpretation, the ruined choirs are the roofless remains of monasteries, the sweet birds the choirs of singing monks. Whichever interpretation is accepted, and both are valid, it is inescapable that the bard was referencing the inevitable march towards decay symbolised by autumn. The cold winds will soon rip whichever leaves cling to claw-like twigs and the landscape settles into a sullen palate, empty of vibrancy.
Yet poets do not always portray autumn negatively. Writing on September 19th 1819 William Wordsworth eulogised the season in Ode to Autumn. Wordsworth, a great nature lover, saw autumn as a time of plenty. The sun will continue to
set budding more, /And still more, later flowers for the bees/Until they think warm days will never cease/For summer has o’er-brimmed their clammy cells.
This wonderful feeling of neverending abundance and the idea of nature’s opulence has far greater appeal than Shakespeare’s bleak vision of loss and decay. Indeed, following one of the greatest summers in our lifetime, surely some optimism is justified. We continue to see Comma butterflies in Carlow and Kilkenny, Small Coppers in Meath and Large Whites, Red Admirals, Peacocks, Small Tortoiseshells and Speckled Woods in Donegal. These sightings, albeit of just a few individuals, allow us to cling on to summer, just!
By contrast, good numbers of moths continue to appear in light traps, some even in spectacular numbers. On October 3rd I counted 177 moths of which 138 were Beaded Chestnuts. This count on a single night exceeds the totals I had for the species throughout its flight period for each of the three years 2015-2017. A count of over 3,000 moths in my garden for the 2018 recording season easily exceeds these previous years’ totals, strongly suggesting that the moths, like our butterflies, greatly benefited from the heat of the summer.
Prolonged heat allows butterflies and moths to move around the landscape to find food, mates and breeding sites. It also allows some species that have already laid their eggs but which can mature a second or even a third batch of eggs to do so. Warmth also helps the eggs, larvae and pupae to develop faster, lessening the time available for predators to eat them. Prolonged warmth will allow time for species that are capable of producing more than one set of adults in a flight season to produce more generations to fly within the same year. This may result in a succession of generations which may even overlap so that the species in on the wing for much longer than it will be in a cooler year. This overlapping of broods was observed in 2018 in the Small Copper. In addition to the heat during May, June and July, the low rainfall levels from May to September inclusive also helped, as wet conditions have been shown to cause damage to the early stages, including, expectedly, the pupal stage.
In many ways 2018 was exceptional. We had an unusually long winter, a bitterly cold, snowy March, a dull, very wet April (remember the fodder crisis?) followed by prolonged hot, dry weather over the following three months giving us the joint warmest summer on record. The dry conditions have persisted into October. Butterflies certainly flourished, and, as recent research indicates, (see https://butterflyconservation.ie/wp/2017/12/08/winter-cold-a-benefit-for-butterflies/ ) cold winters do not harm most butterfly species.
When the cold weather takes its grip, remember the glory of the summer of 2018 and bask in your memory of its splendour. As Wordsworth wrote in Tintern Abbey, these happy memories provide spiritual, emotional and psychological sustenance for the lean times ahead!
Shadows are lengthening, temperatures falling and storms Ali and Bronagh dishevelled and drenched the landscape. Butterflies continue to fly but numbers are inevitably falling.
Summer and autumn flowers are fading fast with many species now in seed to feed Goldfinches and other seed-eaters. There is still floral nourishment available with Common Ivy flowers sticky with nectar and thronging with wasps, flies and some butterflies. Late bramble and Common Knapweed flowers offer food, while some repeat flowering by Common Dandelion is a cheering sight for late butterflies.
Butterfly sightings continue to be made but records are diminishing. There is a tendency to think that butterflies have vanished until next spring because the free-flying adults are harder and eventually almost impossible to find.
Butterflies continue, mainly in immature forms. Many butterfly larvae are extremely difficult to find in the wild, and a number of species have not been found or recorded in Ireland as wild caterpillars or pupae. I know of just two people who have found wild Purple Hairstreak larvae, and no record of anyone finding Hedge Brown larvae or Wood White larvae, to mention just three species. This is not surprising. I have taken 20 minutes to locate a Wood White larvae I knew to be present on cut food plant in captivity. Its camouflage is superb. Not only is the larva the same green shade as the leaves and stems of the plant, but it also aligns itself to resemble a leaflet or part of a stem. It is assisted in its concealment by its highly sedentary manner. The Wood White caterpillar, which leads a solitary life, is feeding now and will pupate late in September or early October. The butterfly will emerge, typically, in May but if there is a cold spring a June/July emergence can occur.
One butterfly that will emerge as an adult this year from the immature forms now present is the handsome Red Admiral. There are many final stage caterpillars and pupae, tented in nettle leaves, out there now. Some adults are emerging now, a process that will continue well into October. The larvae are interesting in that they occur in a range of colour forms, even in the same nettle bed. The colour matters little, as larvae are hidden. This is one of the easiest solitary larvae to find, with droppings often found accumulated in a large leaf below the tented enclosure. Opening the tent will reveal a larva curled in the shape of the number 6. The pupa is a light brown with golden metallic markings. The adult is stunning, especially when seen on a bunch of juicy blackberries or feeding on ivy among the glossy foliage. The adult will hang about for a few days before breeding, or more likely at this time of the year, before heading south to the continent to breed.
The Wall Brown larva is feeding now but finding it is a serious challenge. Features that may help is that it feeds in daylight and basks on bare soil near adjoining grass. The older larva is green with a bluish tint. It loves Red Fescue grass growing in sparse clumps on well-drained soil. Differential growth rates of same-age larvae is a feature of second-generation Wall larvae, with remarkable size variations evident. The fastest growers will sometimes pupate and produce butterflies in October while siblings will take to the air next April or May. Whether October adults breed successfully in Ireland is not known. It is suspected that resultant larvae may be too small to survive the winter.
The Small Heath’s tiny larva is feeding on the tips of finer grass blades. It feeds during sunshine. It is polymorphic, with green, yellow and reddish-brown forms. This larva is very slow-growing until late spring when growth suddenly accelerates. The first butterflies can appear at the beginning of May given a warm, sunny spring. Generally, adults appear later in May and fly throughout June and much of July. Occasionally late butterflies will be seen in late August and September.
While the larva might be seen as the unglamorous stage in the life-cycle, it is extremely interesting. It is the animal’s growth phase and is sensitive to changes in daylight length, temperature, moisture, the nutrient content of the food-plant, the character of its habitat, changes in the habitat and a range of other factors, depending on the species. The interaction between the larva and elements in the environment, such as the relationship between some Lycaenid larvae and ants makes the study of caterpillars especially intriguing. It is the requirements of the larva that often influences whether the species is widespread or highly localised. Finally, in the cooler months of autumn when adults are scarce, larvae offer the butterfly lover a challenge and interest.
The great summer weather of 2018 is over but its benefits, it appears, are still being observed. The Small Copper butterfly seems to have produced three generations and a fourth is still possible!
While butterflies being day-flying are easier to monitor, the results of light trapping for moths indicate that some moths are doing well. From the Garden Moth Scheme which covers all regions of Britain and the island of Ireland as one region comes news of very high figures for some species. One recorder had 356 and 131 Setaceous Hebrew Character moths in his two 15W Heath traps. While only 22 gardens in the Republic of Ireland are part of the Garden Moth Scheme these are trapped on over 90% (97% in May and June 2018) of the nights when trapping is to take place. This high level gives credibility to the results. For 9 out of the 12 regions in the British Isles, the Heart and Dart moth was the most numerous garden moth on average for May and June 2018. (Scotland and North-east England (Hebrew Character) and the Channel Islands (Diamond-back moth) are the exceptions).
We are now looking forward to seeing how the autumn species perform, and last Friday night saw my first record of the Beaded Chestnut, a moth that variable in appearance and often quite numerous during its flight period. The appearance of this moth is one of the signals that the autumnal moth species are about to appear. Other moths which occur now include the Setaceous Hebrew Character, a distinctively marked species whose larvae are found on Common Nettle and two more colourful species, Frosted Orange and Pink-barred Sallow. The Frosted Orange larva feeds on thistles leading one to expect it to be far more numerous than it is. In fact, it is recorded in low numbers, and cannot be assumed to appear in gardens every year. Its ginger peppering, yellow oval markings and brown band means it is attractive and unmistakable.
The Pink-barred Sallow is another pretty species. It shows a broad pink band across canary yellow forewings as its prominent marking with pink mottling above and below the band with the forewing edge pinked out in pink. While it occurs more frequently than the Frosted Orange, small numbers are the norm in my garden. Willows and poplars are the caterpillar’s food plants.
In good habitats, some night-flying moths can sometimes be seen during the day. These are usually observed in tall flower-rich grassland in warm, overcast weather. It provides a rare opportunity to see some species that otherwise can only be attracted to light traps. Like the butterflies, these moths will be found feeding on flowers, especially Common Knapweed, Common Ragwort and Devil’s-bit Scabious. The Silver Y moth flies during the day and night and is very fond of nectar, and will be seen with its typically swift buzzing flight at flowers, fluttering while taking nectar.
To encourage moths to breed in your garden, Grey Willow Salix cinerea and Downy Birch Betula pubescens, native oaks Quercus robur and Quercus petraea, Common Hazel Corylus avellana, Common Blackthorn Prunus spinosa, Common Hawthorn Crataegus monogyna and Common Nettle Urtica dioica are strongly recommended. Planting a species-rich hedge consisting of these tree species might be used to build a habitat in a smaller garden. A large garden allows room for some trees to develop without cutting and this may be more fruitful as some butterfly and moths need tall trees. A garden such as that shown below can be developed to resemble a woodland clearing, with trees, scrub and or hedging surrounding a grassy area containing native flowers. This offers food, shelter and warmth, creating ideal breeding conditions for many moths and butterflies. And a life-filled, exciting place for you, too.
September 2018 opened with sunny days and warm, still nights, ideal for diurnal and nocturnal Lepidoptera. Numbers are still high but the number of species on the wing is falling as we move into autumn. The moth catch in my garden on August 31st consisted of moths that are typically found mainly in summer although many of these were worn. An extraordinary number, for me, was 222 Square-spot Rustic moths. Never have I seen one moth species in such high numbers on a single night. The high number is most likely the result of a great summer. By August 31st 2017, I recorded 1,502 moths in 21 trapping sessions running from March. By August 31st 2018 I recorded 2,358 moths in 22 trapping sessions. The increase is probably related to the much warmer conditions experienced during the late spring and for most of the summer this year. The benefits of larger numbers of moths are enjoyed by our bat and bird populations. I am thinking of the 34 Common Pipistrelle Bats and the 40 or so Brown Long-eared Bats that have occupied my attic for much of the summer.
Unfortunately for day flying butterflies, my garden Robin and Wren are keenly aware of the butterflies available. In particular, the birds are snapping up two species, the Small Tortoiseshell and Peacock. The speed with which a Robin attacks is impressive and while it often seizes the outer part of a forewing instead of the head, cumulative wing damage reduces flight proficiency and increases the chance of capture. One Small Tortoiseshell was found dead with no sign of injury. Was it stung by a wasp? The dramas are compelling to watch and speculate on, but concentrations of prey must lead to high predator activity and high mortality. However, in the case of the fiercely territorial Robin, high availability of butterflies does not lead to a higher number of Robins to prey on them. Furthermore, some butterflies seem to evade birds. From my observation, the birds in my garden either ignore or cannot catch the Painted Lady and Small Copper!
On September 5th a new Small Copper appeared in the garden, dazzlingly copper in the sharpening late afternoon sunlight. The veteran who has been in command of the perch post on a tall ragwort for most of August encountered the new male and battered him away. The new boy must wait his turn! In the evenings I check the shed to count roosting Peacocks and Small Tortoiseshells. The door is left ajar for them and I hope they decide to pass the winter there. Sometimes the Robin goes into the shed too but perhaps the bird has not located the butterflies yet. When the warmth is gone for 2018, the shed door will be shut and the butterflies will be beyond his beak until they depart in spring.
Butterfly numbers in gardens appear to be up on last year and they are abundant in other habitats too. While there may not be as many Painted Lady butterflies this year numbers are quite high. Quite often a good year for this butterfly such as 2017 is followed by much smaller numbers the following year but this has not been the case in 2018 on sites I visit or further afield. From Northern Ireland comes a figure of over 100 seen by Ian Rippey on the County Down coast on August 29th. Recent records suggest that these powerful migrants are more numerous than adult Red Admirals at the moment but there are many Red Admiral larvae still developing, suggesting a good flight of the species later in September and October.
There are still Large Whites, Small Whites and Green-veined Whites around but numbers of these are declining as the season nears a close, but where it occurs, the Brimstone, which overwinters as an adult, is quite numerous. On Saturday, September 1st I saw around 30 of these lovely butterflies apparently hanging suspended on flowers on a cutaway bog in the glorious sunshine. The Common Blue and Holly Blue still fly, as does the Small Copper while in the Burren there may still be some Brown Hairstreaks around. I saw two late Silver-washed Fritillaries on September 1st and one the following day, all males. Speckled Woods are jinking around hedges in good numbers in many areas, and their numbers often peak in mid-September in parts of the west and the Midlands. This butterfly can sometimes extend into early November. Along the west coast newly emerged Meadow Browns confuse observers from the east of Ireland who are accustomed to seeing this butterfly virtually disappear there by mid-August. In some years Clouded Yellow butterflies arrive in small numbers in September and October, giving a final flourish to the butterfly flight season.
We often enjoy beautiful September weather and if so, some short-lived butterflies may live longer, butterflies that over-winter as adults may fly longer and some species may even fit in a partial late generation. Ireland may also get some late migrants. At such times of plenty, we can be persuaded that summer is still with us, and will continue to beam warmly on us. But enjoy the butterflies. We know the cold will banish them soon!
While the comparative analysis of the figures for garden butterflies will be published later, in the Annual Report 2018, it is evident that most species are present in higher numbers in many gardens than in 2017. If you would like to take part in our garden butterfly survey, the details and survey form can be found here: https://butterflyconservation.ie/wp/butterflies/gardening-for-butterflies/
August 2018 has returned to us the more typical Irish summer conditions but the heat earlier in the summer means that there are high numbers of butterflies flying now, which developed quickly in the warm weather that prevailed during the immature life stages. One very important butterfly flying now and during September is the Wall Brown, a butterfly that has seen a marked decline in distribution and range in Ireland since the mid-1980’s. Before the mid-1980’s it was found throughout Ireland in the general countryside but is now mainly restricted to the most free-draining, driest, thinly-vegetated areas such as sand and gravel quarries (probably also found in dimension stone and aggregate stone quarries ), sand dunes, dry coastal heaths, rocky areas such as limestone pavement, dry limestone and acid grassland and the driest areas of cutover bogs. It is absent from many areas inland that it occupied in the past, such as along tracks worn to bare earth on farmland, dry hedge banks and lanes and at the edge of country roads edged by stone walls. It is feared extinct in Northern Ireland where it was last recorded at a coastal site in County Down in 2015. It remains numerous in County Donegal, where, according to excellent recorders, there has been no decline.
The Wall Brown may return to the broader countryside as it is a mobile butterfly and can fly great distances when the urge to move exists. We include two photographs of this lovely butterfly. It is often seen in low numbers but occasionally a dozen or more will be seen concentrated in an area of suitable habitat. It is a sun-loving butterfly. Males are eye-catching. If you see one, he will usually be seen flying low ahead of you, landing periodically to bask against bare surfaces. It holds its wings in a shallow V as it flies. After flying along a track or a stone wall for many metres, it will often turn and fly back, pausing to bask briefly before resuming its patrol. When direct sunlight is dimmed by cloud, the butterfly lands and basks briefly before closing its wings. It is only then that a close approach is usually possible. The female looks similar but is paler overall and does not have the dark brown diagonal band across the upper side of the forewing. Note the presence of white-pupils on black eye-spots. The presence of eye-spots shows its membership of the Satyridae or the “Browns” (regarded by taxonomists as a subfamily of Nymphalidae which includes the fritillaries and vanessids). Other members of the subfamily Satyridae include the Meadow Brown and Speckled Wood.
The Wall Brown shows a similar decline in Britain. It is presumed extinct in Surrey, for example, a southern county that holds many sites containing apparently suitable habitats. Box Hill was one of the last Surrey sites it survived on, and the site continues to hold well-drained, sparsely vegetated grassland one associates with the butterfly. It is the mystery of its decline that adds to the alarm as we have no idea what measures are needed to help it to recover. If you see one on your walk along a country road, on your ramble through flower-rich sand dunes, a cliff walk or anywhere else please let us know, according to the details we need for a valid record; for what is needed please check our website here: https://butterflyconservation.ie/wp/records/
Biodiversity Ireland Issue 17 Spring/Summer 2018 published by the National Biodiversity Centre contains an article by Dr Tomás Murray promoting butterfly recording for the Butterfly Atlas 2021.
The article contains this bleak statistic of Ireland’s declining butterflies: “Ireland (is) identified as being in the top five countries for declines in both widespread and specialist species, out of 21 countries assessed”.
It continues: “For the 15 species where we have sufficient information, our monitoring schemes reveal that seven of those species are in decline compared to three increasing, two stable and three that are too variable to assess”.
Is it that bad?
From what I see on sites I visit regularly, and from parts of the countryside I see from time to time, there are changes in butterfly populations. Without even attempting any population monitoring, it is clear that butterfly populations have undergone significant changes. This is evident when observing the changes in land use. Habitat specialists, in particular, are unlikely to survive for long in areas where their habitats are altered or destroyed by being replaced by golf courses, built on, afforested, drained, mined, cleared, modified by application of chemical fertilisers, ploughed and re-seeded, etc. In habitats not directly altered or destroyed, butterflies can be affected by gradual changes, especially by successional changes in vegetation and by changes to adjoining land such as flooding, drainage, tree-felling or tree-planting, planting of invasive plant species (such as cotoneaster) and other alterations. Natural factors such as coastal erosion, severe in some areas, results in changes to habitats and sometimes to the destruction of high-value conservation land.
It is easy to be pessimistic for the future of our butterfly populations, especially about our habitat specialists. My recent visit to the area south of Lough Corrib, County Galway engendered much despondency in me. This area, north of the N59 towards Lough Corrib between Moycullen and Oughterard contains a variety of habitats, especially bog, calcareous grassland, limestone pavement, scrub and woodland. A number of important habitat specialists have been recorded from the area. These include the Brimstone, Dingy Skipper, Brown Hairstreak, Small Blue, Pearl-bordered Fritillary (in the 1980’s), Marsh Fritillary and Large Heath.
On my visit, I encountered many new, often out-sized individual houses (with boundaries starkly proclaimed by laurel and Leylandii hedging) imposed on what appeared to have once been great habitat. I observed peat being gouged out of the bogs, parts of which have been converted to fairly unproductive agricultural grassland. Rough walls, composed of natural limestone pavement and boulders ripped from rare karst habitats are frequent in the area. It appears that few areas of untouched limestone habitat remain. In one area I examined off the local road from the N59 to Carrowmoreknock, bog grades into limestone grassland, limestone outcrops and scrub habitats. Flowers characteristic of grassy bog and limestone grassland almost have their petals touching. But the limestone pavement that once existed is no more, the limestone slabs torn up to form monumental walling. The area has clearly lost some value. It is likely that Grayling and perhaps even Pearl-bordered Fritillary flew here, but no longer. However, clearing the limestone pavement appears to have rebounded on the farmer, as that area is now buried in dense scrub. Marsh Fritillary breeds on the sward where bog grades into limestone grassland, quite likely assisted by the livestock grazing taking place.
When special habitats like these are degraded or destroyed despair deepens, as the count of precious places with their associated butterflies decreases. Once limestone pavement is ripped up, there is no chance of restoration. The habitat is gone. There are species that will not survive when this damage is done. There will be no return.
Some habitats of special character are designated as Special Areas of Conservation and therefore legally protected. However, the Special Area of Conservation that lies west of Carrowmoreknock, Gortnandarragh Limestone Pavement, has been damaged by quarrying and conversion of part of the area to farmland. Protection clearly needs to be enforced! Even when sites are protected they are sometimes unmanaged leading to undesirable successional changes in the vegetation, causing habitats to deteriorate. In the circumstances outlined above, it is easy to see that habitat specialists are likely to be in decline, and why.
What about the general countryside butterflies, the ones that breed in a broad range of habitats? Even a glance at the general farmed landscape suggests evidence for declines. Many semi-natural grasslands formerly very rich in butterflies are ploughed and re-seeded with one or two grass species and heavily fertilised. Some remaining semi-natural grasslands are heavily dosed in fertiliser annually, resulting in a habitat that excludes many of the food plants butterflies and moths need. Some semi-natural grassland has been ploughed up and planted with non-native conifers. Hedges and hedge banks are severely cut or even removed. Ponds and wet areas are drained or farming ceases, and formerly good habitats that were well managed by rough cattle grazing deteriorate. The inappropriate management of our public spaces, such as parks and canal banks where vegetation is cut when butterflies are feeding and breeding are further examples of drivers of decline. Given these grim circumstances, why are some butterflies doing well?
Firstly, let consider the species that are showing increases in population size (abundance) and in distribution (area occupied). Based on my observations, the resident species that I believe are showing increases in population size and distribution are Cryptic Wood White, Brimstone, Holly Blue, Peacock, Comma and Silver-washed Fritillary. The Speckled Wood is likely to be stable or possibly increasing. While the article quoted above mentions that three species are increasing, I believe that six species are increasing. Interestingly, all of these are found in woodland and woodland edges but other habitats are used by some of these butterflies. Wooded areas are increasing in Ireland. Some are arising from the abandonment of farming, some are planted, some existing woods are spreading and some woodland is new, developing on cutover bogs and on limestone pavement.
To take each of these butterflies in turn, the Brimstone is benefitting from the development of its larval food plants on cutover bogs. The food plants are developing in areas that used to be wet raised bogs and the spread of the butterfly into these areas suggests a genuine increase in distribution. The development of scrub containing the Brimstone’s food plants on eskers, rough hillsides, abandoned quarries and on limestone pavement is also helping the butterfly.
The reasons for the Holly Blue’s increase are harder to assess. It was, before the 1990’s, largely restricted to old woodland near the coast in Ireland but has spread inland to hedges, wooded lanes and even rural gardens, although it was found in large urban gardens before the period of expansion. The increase in woodland is likely to be a factor but a warming climate is likely to be more significant. In Britain it is very rare or perhaps absent from Scotland and rare in Northern England, reflecting its sensitivity to cooler climates.
The Peacock has probably benefited from the increase in warmth too, suggested by its increase in a cooler Northern Ireland which has been ongoing since the mid-1990’s. It is still found in smaller numbers there than further south. The increase in nitrate fertiliser usage over the past few decades benefits its larval food plant, the Stinging Nettle, which may be more vigorous, numerous and nutritious as a result. The Comma, a recent and continuing colonist, is likely to be benefiting from the same factors as the Peacock. There may be additional factors behind the Comma’s rise. It may have developed a preference for use of the abundant Stinging Nettle as a larval food plant, rather than relying on plants such as Hop, which is rare in Ireland.
The Silver-washed Fritillary is a woodland butterfly, breeding on violets growing in well-lit woods. When plantation forestry is cut down, the non-crop tree species are frequently left to grow among newly sown sapling trees, ensuring that woods are not clear-felled and that some shade remains. The light admitted after decades of darkness may make some of these areas suitable for the Silver-washed Fritillary especially a few years after re-planting. Edging conifer plantations with native trees may create habitat, even if this is simply a thin belt of woodland adjoining the arboreal slums of mature, modern non-native coniferous plantations. Even when plantations do not have a cosmetic band of native broadleaf trees added, a scattering of willow and birch seed often germinates along the edges, with Silver-washed Fritillary habitat developing over the following two decades. The growth of tall scrub and trees on abandoned farmland creates habitat too. The butterfly is turning up in the new semi-natural woods colonising the cutover bogs and tall scrub on limestone pavement. Some of these areas now boast large and extensive populations. In addition, some conifer plantation woodland planted on bogs develops poorly, with some trees dying after 20-30 years, leaving gaps that open up the ground to light and suitable vegetation. The dark cloud cast by the demise of Large Heath’s wet bog habitat is the Silver-washed Fritillary’s silver lining.
The Cryptic Wood White loves to fly and breed along sunny herb-rich wood edges, so is in its element along the access tracks through woods and along the edges of new wooded areas. The fact that it looks superficially like some other white species may result in it being under-recorded, but I believe it is doing well. It even shows up in my garden!
To guess which species are in decline is depressingly easy. I will mention a few here. The Dark Green Fritillary cannot be doing well in its main habitats. Its preferred habitat, unfertilised flower-rich grassland is quite rare now outside the coasts. For the same reason, Dingy Skipper, Small Blue, Common Blue, Small Heath, Wall Brown and many other semi-natural grassland dwellers must be in trouble. There are likely to be additional reasons for the fall and fall of the Wall Brown but these are not clearly understood.
However, we need hard data. My observations do not count without robust, scientifically reliable statistics. The records being sent to Butterfly Conservation Ireland from 2017 to 2021 will be used along with records collected by Butterfly Conservation Northern Ireland and the National Biodiversity Data Centre to compile an All-Ireland Butterfly Atlas in 2021. Please send us your butterfly records. We explain how to do this here: https://butterflyconservation.ie/wp/records/
We have images of all Ireland’s butterflies here to help you identify our butterflies: https://butterflyconservation.ie/wp/gallery/
The other measures you can take concern habitat protection and habitat development. Report any damaging activity you see taking place on any protected site to the National Parks and Wildlife Service. Insist on receiving information on how your concerns are followed up. The full list of Special Areas of Conservation and Special Protection Areas are here: https://www.npws.ie/protected-sites.
The data you send us will be used to create the Atlas and to update the Ireland Butterfly Red List, due to be updated in 2020. Armed with this data, we will be able to press the state for better protection and management of our landscapes so that there will still be some wildlife-rich areas for you and your children to enjoy and for our butterflies and moths to live in.
August is a busy month on the reserve at Lullybeg. Some butterfly species are busily feeding as adults or as larvae, racing to feed up for the winter. Other species are feeding to build reserves for migration or breeding. Individual adult butterflies of some species can either over-winter as adults or breed now (Small Tortoiseshell) while other species may breed now or prepare to migrate (Red Admiral). The potential for this flexibility may depend on a range of circumstances (such when the adult emerged) and conditions (weather, the condition of the larval food plant, etc). These complications and possibilities add variety and interest, and the observer can scan for clues as to the strategy used by species that have the capacity to be flexible. These clues will be seen in the behaviour. Are the male butterflies concentrating on feeding or on establishing territories and pursuing potential mates? Are females focussing on feeding or fluttering around the larval food plants?
For an example of a butterfly that can be flexible in its approach at this time of year, let us look at the Small Copper. The second generation of this species is flying now. This elegant little butterfly is now breeding. Some of the butterfly’s offspring may, if sunlight, temperature and food plant quality are suitable, become adult butterflies this year. These will fly in late September and in October. If the conditions do not allow for a third generation of the Small Copper or are marginal, most or all of the autumn larvae will endure winter hunkered down deep in the vegetation to resume feeding when spring arrives. These will reach the adult state next May or early to mid-June. I counted eleven of these sparkling starlets on the reserve today, a good tally for a butterfly usually recorded in low single figures.
Several butterfly species have their entire population in the larval stage now. The Marsh Fritillary butterfly is strengthening its population at Lullybeg, with 31 larval nests found on the reserve so far. I watched larvae feeding today, some outside their webs, nibbling in unison at the upper epidermis of the leaves of their sole food plant, Devil’s-bit Scabious. Some larvae are in their first instar while others have moulted their skins once to reach the second instar. The larvae may need to reach a healthy weight before their final moult later in autumn when they reach the fourth instar. Some species will not survive winter unless the larva reaches a certain instar before cold weather bites. The Speckled Wood is an example of this urgency. I suspect that the Small Heath larva must also reach a certain stage before winter if it is to survive.
Some butterflies don’t have these worries. The last Dark Green Fritillaries of the season was probably the tattered trio I saw on August 3rd. Their larvae, and the larvae of its bigger cousin, the Silver-washed Fritillary, hatch after two weeks, consume the eggshell and hibernate. The larva fasts for at least seven months before seeking violets to feed on. However, the larvae do have some concerns. They must not be discovered by birds, beetles or spiders. They must hope that their mothers placed them in the best conditions for over-wintering and feeding when the time comes. For the Silver-washed Fritillary, the egg-site is a cool, shady spot on a tree trunk, often on moss or half-hidden by ivy or in a crevice in a tree trunk. The Dark Green Fritillary lays her precious egg among dense, cool grass tufts with violets close by or among the tangle of grass. The cool conditions are chosen so that the tiny unfed larva does not shrivel in the August and September heat.
Life is simple for Brimstone butterflies. Feed up. That’s all they need to do. There is no complicated multi-brood strategy for our longest-lived adult butterfly. Just get as much Common Knapweed and Devil’s-bit Scabious nectar as possible before vanishing in September or October until the sun’s heat returns in mid-March.
There is so much going on now, with vast flights of ladybirds, bees, flies, dragonflies. All are racing against summer’s diminishing hour-glass. Before the sands of summer slip through your fingers, get out and savour what’s left.
Here we are in August, a month of grandeur for the special jewels of our landscapes. Below are some butterflies found this month, all recently photographed. What a summer we continue to have!
Common Blues are seemingly everywhere, even turning up in gardens where some are breeding. Some individual Common Blues are much smaller than they should be, no doubt products of drought conditions reducing the food available to the larvae. I peered hard at a couple today, so diminutive as to suggest a Small Blue.
Small Coppers are widespread but not numerous but this is typical of this lovely creatures population dynamic. No photograph can really represent its sparkling copper upper surfaces, so here I opt for a more sombre photograph of its undersides, still elegant and interestingly distinct from British populations. British Small Coppers usually have brown rather than grey undersides with a lesser defined, more subdued reddish hindwing band than the ones that grace our flowers.
Peacocks seem to be launching a takeover attempt at the moment. I am rarely shocked at their population sizes on good sites but the swarm encountered at a special site recently left me gaping in admiration as a blur of reds, golds and purples swirled in the sunshine! Never spray your nettles, the plant it breeds on!
The Brimstone is out in numbers now in its midland haunts, dawdling for several minutes at favoured Common Knapweed blooms, oblivious to bees jostling for their share.
Small Tortoiseshells are just beginning to show up in gardens, fields, parks and wood edges now, and will build their numbers to outnumber the Peacocks. Alas, when this happens, we know autumn is upon us!