Butterfly Season continues in Larval Form

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 one record of wild Purple Hairstreak larvae, and none of 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 some time in 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.

Photographs © J.Harding 2018.

Red Admiral larva, pale form.
Wall Brown caterpillar.
Wood White larva on Tufted Vetch.
The Small Heath larva grows slowly. This larva measures 10 mm and is c.90 days old.

September Moths

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.

Photographs © J. Harding 2018.

Setaceous Hebrew Character, numerous in 2018.
Beaded Chestnut, an autumn moth.
Frosted Orange, an uncommon moth in gardens.
Pink-barred Sallow, a beautifully marked moth.
Gardens planted with a range of native trees, shrubs and herbaceous plants are rich in moths.

September Butterflies

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/

All photographs © J.Harding 2018.

At this time of the year, the Painted Lady feeds to prepare for migration. In years when it is abundant, high numbers can be present in flower-rich habitats in early September.
The Speckled Wood, a hedgerow and woodland butterfly flies from April to November with some short periods of scarcity during its long flight period.
Female Common Blue basking, Kildare.
Small Whites mating. Egg-laying is taking place now.
The Brimstone engages in prolonged pre-winter feeding during good weather in September.
A newly emerged Small Copper.
The Small Tortoiseshell basks during cloudy spells. When direct sunlight returns, the butterfly resumes its pre-winter feeding.
The Clouded Yellow may arrive from Europe in September and October.

 

 

 

One to Watch (if it still exists)

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/

Male Wall Brown basking on limestone at the side of the road at Gortlecka leading to views of Mullaghmore, Burren National Park, County Clare.©J.Harding.
Wall Brown underside.©J.Harding.

Is it that bad?

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.

Finally, build butterfly-friendly habitats in your garden, public space (as part of a local environmental group) farm, etc. Advice on how to do this (never replace one good semi-natural habitat with another habitat without very good reasons) is given here: https://butterflyconservation.ie/wp/butterflies/gardening-for-butterflies/

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.

The Peacock butterfly, a widespread general countryside species that is increasing.©J.Harding.
Damage done to limestone pavement destroys special karst habitats and destroys habitat specialist butterflies.©J.Harding.

Event Cancellation

The forecast for Saturday, August 11th is unfavourable for seeking butterflies. It appears that it will rain for much of the day and the conditions forecast for Sunday appear to be similar.
The outing to the Burren planned for Saturday, August 11th is therefore cancelled. We regret any inconvenience caused.

Lullybeg Reserve Update August 2018

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.

Small Copper, female.©J.Harding.
Marsh Fritillary second instar larvae feeding.©J.Harding.
The first Dark Green Fritillary recorded on Lullybeg reserve in 2018. The flight period is ending now.©J.Harding.

August Butterflies

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!

Common Blue female.©J.Harding.
Common Blue male.©J.Harding.
Small Copper underside, female.©J.Harding.
Peacock.©J.Harding.
Brimstone, male.©J.Harding.
Small Tortoiseshell.©J.Harding.

 

Garden of Eden

Eden translates as delight. And this is what butterflies bring, especially to our intimate outdoor spaces. They bring personal excitement because for gardeners the boundary line between indoors and the great outdoors is blurred in the garden. The garden is a personal space, especially gardens that are secluded, private, personal havens where we can be ourselves, sometimes more than it is possible to be in the house because there we must toil. We must carry out the necessary tasks in the house. In the garden, we can choose to act or not.

In a garden to act is often to create. We can create living spaces for our fellow creatures, or choose not to. Yesterday, I spoke to a friend about his front garden. He had removed rather unkempt but Small Tortoiseshell bedecked lavenders with red-flowering begonias and a house geranium. I peered for a moment to assure myself that the new plants were not plastic.

“Why did you do that?” I queried, mystified because I know that he loved watching the tortoiseshells.

“Oh, the bees kept flying into the house”.

“You won’t have any more bees, don’t worry. What you put in here will not be touched by any bee or butterfly”.

In this case, the house has extended into the garden.  The garden has become tame, a place where plants are cabinet or mantelpiece ornaments.  There is little interaction now between man and nature, which has been discouraged.

Today, in many areas, butterflies are being rendered homeless. In the developed landscapes of our cities and towns as well as in the more sterilized intensively managed countryside we need to provide safe havens. Create opportunities for life to fill your garden. Butterflies can make your garden their home, with a little thought and the correct choices and actions. And there is the pleasure that grows from knowing that these butterflies, free though they are, are ‘your’ butterflies. You may even get to know individual butterflies. A kink in a wing and you know that you saw this one yesterday. Some butterflies pause for minutes but some stay for days, even weeks. One Common Blue remained in my garden for nearly a month. I said good morning to him each day until his time on earth was done. I miss him still.

Some butterflies seem to want to know you. From early July to late September each year, a small number of my garden’s Small Tortoiseshells enter my house to roost during wet weather or for the night. These stay inside for days when it is cold or raining, typically perched on a wall, ceiling or curtain until sunshine returns. Then he or she finds his or her way out through an open door or window. The occasional butterfly will roost in the house every night, leaving when it warms up the following morning. The Small Tortoiseshell is, of course, a species that passes the winter as an adult butterfly, so the individuals that come indoors regularly in autumn have already decided on their winter abode. Very occasionally, the Peacock butterfly will enter your house to stay for the winter.

Everyone knows that butterflies like nectar but not all flowers have this food.  Select true species, avoid cultivars. Most lavenders contain nectar, so does Buddleia davidii, Common Knapweed, Common Marjoram, Common Fleabane, Purple Loosestrife, Water Mint, Red Clover, Common Bird’s-foot-trefoil, Devil’s-bit Scabious and Wild Angelica to name a mere handful of flowers. All easy to grow, all perennials, all sure to draw in lots of butterflies if planted in sunny, sheltered terrain. A nettle patch against a sunny hedge or wall for the Vanessids (Red Admiral, Peacock, Small Tortoiseshell, Comma) to lay their eggs on and you will have the butterflies using your garden as a breeding site too. If your hedge has Common Holly, Spindle. Common Buckthorn, Alder Buckthorn among the Common Hawthorn you will be likely to attract many moths and butterflies such as the Holly Blue.

Some ecologists scoff a little at gardens, dismissing these as poor substitutes for ‘real habitats’. This misses some crucial points. Gardens can be managed to suit butterflies in ways that many wild habitats cannot be, simply because of a lack of resources. Gardens can have a greater range of habitats crammed into small spaces than wild areas usually contain. Gardens mark the immediate interface between man and nature and being personal spaces, we are much more likely to take personal responsibility for what happens there. While gardens will never be habitats for the more localised, specialised butterflies and moths unless the gardens adjoin these habitats and might be considered part of them, a large proportion of our butterfly and moth species have been recorded in gardens. The more effectively the larger garden is managed for nature, the more attractive it becomes for butterflies and moths, and other wildlife.

Some of the rarer, more habitat specialist butterflies have been recorded in Irish gardens. These include the Brimstone, Silver-washed Fritillary, Green Hairstreak and Wall Brown. The Comma, a recent arrival still spreading from the south-east has already been spotted in Irish gardens. In the past two days, July 15th and 16th, I have seen Large Whites, Small Whites, Green-veined Whites, Small Coppers (three stubborn males bitterly contesting the same perch post on a Common Knapweed), Holly Blues, a Painted Lady, Small Tortoiseshell, Peacock,  Meadow Browns and Ringlets in my garden. A few weeks ago, a Common Blue peppered the Black Medic plants pushing up through gaps in my patio stones with eggs, so I hope to see her offspring in August.

Gardens offer a great way of tracking the fortunes of our butterflies, particularly the widespread species. Get involved in our garden survey; here’s how to do this:

https://butterflyconservation.ie/wp/wp-content/uploads/2017/12/National-Garden-Butterfly-Survey.pdf.

See the advice on gardening for butterflies here:  https://butterflyconservation.ie/wp/butterflies/gardening-for-butterflies/

Finally, gardening for butterflies encourages bees, grasshoppers, amphibians, birds – all of these groups can do with your care and concern.

Here are some butterflies in my garden. Why not entice them into yours?

Peacock butterfly.©J.Harding.
Holly Blue.©J.Harding.
Small Copper.©J.Harding.

July Butterflies

The hot, dry weather continues as 2018 is turning out to be a memorable, once-in-a-generation summer here in Ireland and in Britain. However, the dry conditions may pose trouble for species that breed on herbs on thin soils now affected by drought and for the grass-feeders especially those that breed on grasses in open, unshaded areas on thin and well-drained soils.

It has been a bumper year for Marsh Fritillary, now finished flying for the year. The butterfly has been expanding its distribution by taking advantage of the warmth to fly beyond the often narrow confines of its sites to seek breeding ground further afield. Another butterfly that does this is our largest native butterfly, the Silver-washed Fritillary. In early July it is at the start of its flight period and fresh examples look really magnificent so get out to the woods and look along the tracks where flowering bramble occurs. The Silver-washed Fritillary is unlikely to be missed if present. The large size, dashing yet graceful flight and deep orange upper sides marked with black bars (male only) and black spots (both sexes) make it a striking butterfly.

Avoid confusion with its slightly smaller but even faster-flying relative, the Dark Green Fritillary. The males of both species look quite similar on their upper surfaces but the undersides differ more clearly. The Silver-washed Fritillary lives up to its name by having washed silver bands on a greenish hind-wing, while silver spots on a greenish background indicate a Dark Green Fritillary. Each species preferred habitat is often different, with Dark Green Fritillary preferring more open, grassy sites but the Dark Green Fritillary may appear in large clearings in woodland and along some wood edges where the Silver-washed Fritillary flies.

The first generation of Small Tortoiseshells is flying, but most of these will not fly for long. The majority will remain on nettle beds, breeding to produce a long-lived second brood most of which will pass the winter as adult butterflies. A small number of first generation Small Tortoiseshells will not breed this year but will over-winter together with the second generation butterflies. However, some second-generation adults may breed this year to make a third brood, especially if weather conditions allow. The result of delayed breeding is that up to three generations of Small Tortoiseshells may be spending the winter as adult butterflies. The majority of over-wintering Small Tortoiseshells will be second generation adults that emerged as adults towards the end of August and during September.

Green-veined Whites will build their numbers to peak later in July, while Small Skipper and Essex Skipper butterflies are on the wing now, the latter in County Wexford where good numbers have already been seen. The new generation of Brimstones is beginning to emerge and unsurprisingly given the heat it is appearing earlier this year. Earlier emergence may mean it is active for a longer time and this will probably result in higher numbers being predated before it retires to scrub and woods to pass the winter as an adult butterfly.

Less evident but no less interesting are the larvae present now. Peacock larvae are finishing their growth and the Small Blue larvae are departing their disintegrating Kidney Vetch flowers to seek sanctuary in the substrate below.  They can be seen now on good sites feeding openly on the seed on the now flimsy inflorescence.  Some will be seen on stalks, heading downwards. These larvae will pass the next eight or nine months as fully-fed larvae. These will pupate from April to fly in May and June. Timing is everything for the larvae; they need to be full-grown by the time the food plant’s seed (the part of the plant the larva feeds on) falls to the soil. If not fully-fed by then, it is likely to starve. Some have probably starved already, as many Kidney Vetch plants on sand dunes have expired in the arid, rainless weeks. Expect less Small Blues next year where the plants have shrivelled.

Now follows a butterfly seen only by the fortunate or extremely dedicated searcher. The Purple Hairstreak is a tree-top dweller flying now in oak woods or woods containing oaks. However, it is very limited in its known distribution in Ireland because of the scarcity of oak woodland and woodland with good stands of oaks. Binoculars are the usual method of discerning it high up in the leafy oak tops, spinning in the sunlight in a delicious combination of purple and silver. The oak woods in County Wicklow are probably where the highest populations occur but the oak woods in Killarney National Park are reputed for its Purple Hairstreak numbers. The oaks adjacent to the American Embassador’s residence in the Pheonix Park, Dublin also has the butterfly in very good numbers.

This year Ringlets are superabundant in their favoured habitats but a concern exists for the numbers expected next year. The larvae feed on lush grasses growing in areas where some shade exists. The heat and drought, if it continues for another few weeks, may lead to a deterioration in its grasses, but these conditions are perhaps even more likely to reduce the ranks of next year’s Meadow Browns, which prefer grasses growing in open conditions bearing the full desiccating impact of hot dry weather.

However, these common butterflies will bounce back in the following seasons given the return of rain which will renew butterfly food plants. But for now, just enjoy July 2018.

Silver-washed Fritillary male. ©J.Harding.
Silver-washed Fritillary underside. Note the silver band crossing near the centre of the hindwing.©J.Harding.
Dark Green Fritillary male.©J.Harding.
Dark Green Fritillary underside. This has prominent silver spots on the hind-wing. © J.Harding.
This female Brimstone emerged from her pupa on July 8th at Lullybeg, County Kildare. ©J.Harding.
Small Skipper female.© J.Harding.
Essex Skipper female.© J.Harding.
Purple Hairstreak.© J.Harding.
Small Blue larva, head downwards, feeding on Kidney Vetch seed.© J.Harding.