Author: Jesmond Harding

The day was hazily sunny before noon, but soon after midday the clouds faded and the sun shone on our day. The Mornington dunes are part of the Boyne Coast Special Area of Conservation for three sand dune types-embryonic shifting dunes, shifting dunes along the shoreline with Marram, and fixed dunes with herbaceous vegetation.  Kidney Vetch. the flowering plant needed by the endangered Small Blue can be found on all three dune types, especially the latter two.  The fixed dunes are particularly rich in flora with Bee Orchid (scarce this year), Pyramidal Orchid, Common Cat’s-ear,  Wild Thyme, Wild Pansy, Common Ragwort, Kidney Vetch, Common Bird’s-foot-trefoil, and Red Fescue all abundant.

We were particularly looking for the Small Blue (very well-named for its size!) and the showing did not disappoint. The butterfly was everywhere we looked, from the newest to the most established high dunes backing onto the golf course. At times half a dozen could be seen jinking at the crest of a dunes-males checking the breeze and passing butterflies for a female. Females were observed laying eggs and rejecting plants, presumably because these already held an egg. Many of the butterflies looked fresh, although worn specimens were readily seen.

Skylarks and Meadow Pipits were vocal, adding to the wild atmosphere. Initially few Small Heaths were found but as it warmed these appeared in good numbers, with areas of matted fescue being favoured. Here, at least, this declining butterfly remains numerous. Meadow Browns, all new males, were extremely elusive and wild. These have not yet settled into their typical behaviour of searching patiently for females.

Because the dunes we reached from the car park were so productive, we did not venture too far but took the time to observe and tried to photograph the highly skittish Small Blues. The males have the annoying habit of resting with wings extended but darting off at the sight of another butterfly, leaving the photographer with a blurred photo or a photo of an unoccupied grass blade. However, the challenge of getting that perfect photograph is part of the enjoyment.

While pursuing butterflies to obtain photographs might be seen as a one-dimensional approach to nature study, I disagree. Much can be learned from an image. The butterfly’s orientation, stance, activity, choice of perch, the time the image was taken can tell us much about the creature’s ecology-don’t knock photography.

There was one fly in the day’s ointment. We received news of a proposal to construct a cycleway through the dunes which will enable cyclists to travel from Laytown to Drogheda. This is a disturbing idea. The dunes represent the best flower-rich habitat in County Meath and are protected under EU and Irish law. They also hold possibly the highest population of the endangered Small Blue butterfly in Ireland. The mania for cycleways should not destroy natural habitats. If there must be such an amenity, build it on the adjacent golf course.

Leave the dunes to nature. They are perfect as they are.

Thanks to everyone who came along. Your company made the day a great pleasure.

 

 

Kildare Conservation Groups announce a major drive for a new 7,000-hectare National Peatlands Park in Kildare and Offaly.

• Proposed Bog of Allen project offers potential for job creation, eco-tourism, and opportunities in research, science, conservation, and archaeology.
• The core aims of the group are to reverse biodiversity loss, save valuable peatland habitats, create landscape-scale parklands and empower local peatland communities.
• Irish Peatland Conservation Council, Lullymore Heritage and Discovery Park, Umeras Peatlands Park, Wild Kildare, Kildare Bat Group, Butterfly Conservation Ireland, and Birdwatch Ireland are advancing the initiative.

Seven local and national environmental organisations this week presented their proposal for a major new 7,000-hectare National Peatlands Park in Kildare and Offaly, at a meeting with Bord na Móna. The Group presented their proposal to Government and to the Strategic Policy Committees in Kildare County Council. The proposals have received endorsement by the Committees and have been identified for attention in the proposed new County Development Plan for Kildare.

Ireland is currently in a climate and biodiversity emergency.

• Peatlands are the largest store of terrestrial carbon in the world.
• Globally only 3% of the world’s landmass is peatlands. In Ireland, it is 20%.
• Peatlands store over three times as much carbon as rain forests.
• We also know that the world’s peatlands, while only covering 3% of the Earth’s landmass, contain twice the sequestered carbon of all the world’s forests combined.
• In Ireland 75% of our terrestrial carbon is stored in peatlands.

Jesmond Harding, spokesperson for the Peatlands National Park Group said:

“What we have in Ireland is unique and is the envy of the scientific world. The cessation of peat extraction in Ireland presents a once-in-a-lifetime opportunity to save and preserve what we can and to create new wetland and heathland habitats across our central plains. The restoration and rehabilitation of this landscape will support Ireland’s work towards our net-zero emissions by 2050. It will create space for the biodiversity, amenity space for people and eco-tourism potential.”

The Irish Peatlands Conservation Council, Lullymore Heritage and Discovery Park, Umeras Peatlands Park, Wild Kildare, Kildare Bat Group, Butterfly Conservation Ireland, and Birdwatch Ireland have come together to drive a proposal for a new National Peatlands Park on a landscape scale in the Bog of Allen centred in County Kildare. The proposed study area is over 7,000 hectares. The objective is to rewild and restore the cutaway peatlands following the cessation of industrial-scale peat extraction, creating a National Park similar in ambition to world-famous parks such as The Peak District, The Lake District, and the Broads National Park in the UK. These national parks generate billions in revenue for the UK economy and create tens of thousands of jobs in their vicinity.

The National Peatlands Park Group says this initiative will benefit communities, the environment, and the economy. The Group is particularly concerned about the animal populations under pressure in our local area. The Curlew is a species that has seen a 98% decline in population since the 1980’s. One of Europe’s legally protected butterflies, the Marsh Fritillary, and the iconic raised bog specialist, the Large Heath Butterfly, are facing extinction in many areas.

Jesmond Harding added: “The Bog of Allen is unique in terms of scale and holds the potential for a true wilderness experience. The variety, beauty and number of species in this area is unique in Ireland and not only should it be protected, but it should also be available for us all to experience and enjoy. The designation of National Park Status for this Peatlands region will deliver multiple benefits. It will protect and greatly increase biodiversity, mitigate climate change, enhance the social and economic life of midland communities and act as a catalyst for a growing sustainable tourism industry.”

The proposed National Peatlands Park would be located on Bord Na Mona cutaway bogs in Kildare and Offaly and would complement the great work in rehabilitation that Bord na Móna are currently engaged in under their Peatlands Climate Action Strategy.

-ENDS-

For further information please contact the spokesperson for The Peatlands National Park group, Jesmond Harding at conservation.butterfly@gmail.com

Notes to the editor:

About Irish Peatland Conservation Council

The Irish Peatland Conservation Council (IPCC) mission is to protect a representative sample of the peatlands of Ireland for people to enjoy today and in the future. The IPCC is a registered charity (Revenue Number CHY6829 and Charities Regulator Number 20013547) and a non-governmental organisation. The Council’s work includes purchasing and protecting peatland nature reserves for wildlife and habitat conservation, maintaining a database of 1150 peatland sites of conservation importance in Ireland, developing a Strategy for the Conservation of Peatlands in Ireland, providing resources and training for teachers and education groups, promoting environmental awareness and publicity, conducting research into the restoration of man-modified peatlands, fostering a positive attitude towards peatlands, encouraging lifestyles in harmony with the environment and fundraising.

About Butterfly Conservation Ireland

Butterfly Conservation Ireland (BCI) is a volunteer-run non-governmental conservation charity (Revenue Number 18161, Charities Regulator Number 20069131) founded in 2008 in response to the declines of our butterfly populations. We are dedicated to the conservation of butterfly habitats. We have a reserve in Lullybeg in County Kildare which we run with Bord an Móna where conservation is applied to protect the excellent habitats so that the extraordinary butterfly and moth populations continue to thrive. We manage a reserve in the Burren in conjunction with the Burren Conservation Volunteers to protect Ireland’s rarest butterflies. Butterfly Conservation Ireland runs a recording scheme with the National Biodiversity Data Centre in a joint initiative. Butterfly Conservation Ireland holds events to showcase butterfly conservation and we provide regular educational content on our website and in our Annual Report. Butterfly Conservation Ireland advises on the conservation of butterfly habitats and advocates to urge the protection and correct management of our landscapes.

About Birdwatch Ireland

Birdwatch Ireland is a science-based conservation charity and the largest independent conservation organisation in Ireland. The primary objective of BirdWatch Ireland is the protection of wild birds and their habitats in Ireland. Birdwatch Ireland has 15,000 members, 2,000 active volunteers, 30 local branches across the nation, 450 events free to the public every year, and 116 partners across the globe in BirdLife International

About Lullymore Heritage and Discovery Park

Lullymore Heritage and Discovery Park is a social enterprise day visitor attraction offering over 60 acres of serene woodland and peatland trails, in Ireland’s most famous peatland, the Bog of Allen in West Kildare. The Park is a key resource in the region, providing a range of experiences such as education on peatland biodiversity and history, as well as leisure and play. The facility caters to visitors of all ages, school tours at pre-school, primary, and secondary level, language schools, families, corporate events, and international tour groups. Lullymore Heritage and Discovery Park is a national award-winning enterprise (ITIA Best Environmental Tourism Innovation 2017) and attracts over 50,000 visitors annually.

About Umeras Peatland Park

Umeras bog is approximately 750 acres, comprised of 650 acres of cut-away bog, 40 acres of raised bog, and 60 acres of birch woodland, drains, bog railway, and a works yard located near the Grand Canal between Monasterevin and Rathangan. The objective of local community group Umeras Community Development is to transform Umeras Bog into a peatlands park as a local and tourist amenity. We believe that a Peatlands Park will bring tourists to Monasterevin and Rathangan, which combined with the Blueway and Ballykelly Mills Distillery will rejuvenate the local economy. The Peatlands Park would create direct employment in building and managing the park, and indirectly, by creating demand for cafés, shops, bike hire, accommodation, etc. in Monasterevin and Rathangan.

About Wild Kildare

Wild Kildare is a voluntary group with the aim of promoting, enhancing and protecting the wildlife and biodiversity of Co. Kildare.

About Kildare Bat Group

Kildare Bat Group was launched in 2011, and with the encouragement and support of Bat Conservation Ireland, a Heritage Grant via Kildare County Council, and a committed team of local volunteers, has been going from strength to strength. We are members of Bat Conservation Ireland with a particular interest in Kildare’s bats.

With over 1475 moth species recorded in Ireland, we have a wonderful wealth of species to admire. For every butterfly species, we have 42 moth species. Most moths are strictly nocturnal, and these are rarely found without the correct equipment. Like butterflies, moth species have their specific flight time.  Below is a very small selection of the moths flying now.  I have included the native breeding plants these species use, underlining the need to grow the correct native herbs and trees in our housing schemes, gardens, parks, motorway embankments, woodlands, hedgerows, grasslands, and everywhere plants are planted.

If you would like to see these moths, join us on our moth morning, on June 26th. See https://butterflyconservation.ie/wp/events-2/

Just a trio to highlight the beauty of bogs. To defend their future, and ours, we need to defend the bogs. That means no more horticultural peat, no more industrial-scale peat mining, no landfills on bogs.

And the benefits? Beautiful wildlife: butterflies, Skylarks, Cuckoos,  Curlews, Otters. Clean air: carbon storage. Clean water: flood control. Economic growth: a healthy environment brings tourists to see our landscapes. Education: study how bogs function to stabilize climate, improve water and air quality, and how they function as ecosystems. Recreation: bog walks, rambling, cycling, horse riding, boating.

And all of this for not destroying our bogs…

Free at last! But freedom must be managed with the caution and restraint that characterized our outing but it was so refreshing to be in nature, in great company.

The morning began overcast but mild and the forecast promised sunshine. It kept its word.

Blackcaps and Song Thrushes were sweetly and prominently vocalizing the day’s rapture, and soon the first butterfly, a lovely male Marsh Fritillary, as fresh as the morning, flitted into our ken. Netted then released, he calmed obligingly, wings outstretched, with photo ops for all. What we did not know yet was he was the first of around 100 Marsh Fritillaries (all but one were males) we would see on our ramble, for the sun shone liberally for much of the duration.

Shortly after seeing our first Marsh Fritillary, an erratic flyer in an area of poor fen and wet heath stopped us. A Green Hairstreak, the first I have seen off a bog in Lullymore.  Looking around, the presence of Cross-leaved Heath, a breeding plant, provides a potential context.

Next, we entered the “corridor” linking Lullymore and Lullybeg, expertly managed by Pat Wyse over the winter months to bring in light and regenerating heath to an area under encroachment. Here the amazing Narrow-bordered Bee Hawkmoth reigns-all the ones we sighted as pristine as the Marsh Fritillaries. Some amazing close photos were taken-see below. Again, they posed nicely for us; it was warm enough for activity but cool enough to discourage freneticism.

Marsh Fritillaries love this corridor too, having moved in to breed following scrub clearances. As a result, we now have an almost contiguous breeding habitat extending from the Irish Peatland Conservation Council Reserve in Lullymore to BCI’s reserve in Lullybeg. Brimstone egg-laying, with the female contorting her powdery abdomen in what looks like a painful procedure to deposit her precious egg, was observed close-up. Pat’s clearance means more Alder Buckthorns are now available for egg-laying Brimstones, so they can distribute their eggs over more plants, which may relieve predation pressure on the butterfly.

We passed through the corridor into the BCI reserve, looking fairly flowerless and bleached, but soon the colour of multiple Marsh Fritillaries brightened proceedings. I have not seen so many on the reserve on one day for at least a decade. This made for a momentous visit.

Another butterfly that seems to be thriving on the reserve is the Dingy Skipper-we saw at least 20, most of them in good condition. A large female Red Admiral fussed around some Meadowsweet plants, evidently mistaking the dark, wrinkled leaves for Stinging Nettles. Flashes of red revealed Small Coppers, with one tattered female laying on a tiny Sheep’s Sorrel on bare peat.

Cryptic Wood White, never numerous on the reserve, numbered five during our sojourn-a very respectably tally on this site. The southern side of the reserve was our last stop, and there were Marsh Fritillaries throughout-this is a new development-it was hitherto very scarce here. It is days like this that show that our hard work in managing the reserve is working-our resources are yielding tangible conservation results. This is thanks to all our supporters for all your help, both financial and practical.

We spent over three hours enjoying nature on this gentle, lovely day, enjoying everything from the tiny Small Purple-barred moth flitting jaggedly over the Common Milkwort to the mighty Buzzard soaring proprietorially above us.

I, for one, was delighted to be out. Thanks to everyone who took part in our walk, making the day so enjoyable.

 

 

Lockdown has been hard on people. Long periods without meeting friends and family, without working face to face with colleagues, without playing sports, and following our hobbies with other people are sorely missed. We need other people. That is how we are made.

One of our compensations is nature’s beauty, needed and appreciated more in our restricted circumstances. Bird song really cheers especially during spring when many species are in full voice. The Blackcap is particularly evocative of spring, having a varied, sweet, and melodious broadcast. He sings throughout the day in spring and well into summer. Gardens, woods, and hedges are occupied by this modest-looking bird, which appears to be thriving. Goldfinches, Linnets, Song Thrushes, Blackbirds, Chiff-chaffs are very vocal right now, often singing at the same time, making separating their songs tricky.

A rarer sound now is the call of the Curlew, a sweet but haunting call, made all the more evocative when heard drifting across a vast expanse of bog, surely our wildest and loneliest looking habitat. A dreamy, melancholic repeated note, there is just something mystical about the call, something that stirs in the soul.

So much rarer now, the species is numbered at around 130 pairs, a catastrophic crash mirroring the mass destruction of our bogs. The plummeting population of the Curlew and other birds are well recorded but many species are declining without our knowledge, silently vanishing, having no voice for us to notice their plight.

The mass decline and extinction of species from many areas is a stark underliner of our loss and mortality. By replacing natural habitats with agricultural grassland, we exchange the profound for the banal, biodiversity with impoverishment.  Our sense of place is altered, affecting us culturally and psychologically.  Who can sigh with satisfaction after replacing flower-filled limestone grassland with acrylic green sward nibbled to nothing by sheep? Who beams with pleasure when the character is ripped from the countryside? The ‘blanding’ of our landscapes carries on as I write; there is a hideous human drive, it seems, to ‘improve’ land.  The outcome is that we are all diminished and have so much less to leave to following generations.

In butterfly terms, many losses do not show up on distribution maps. The maps are often produced at the 10 km resolution, which does not pick up local extinctions. In some of these 10 km squares, a population of a particular species is confined to a single site but the map gives the impression that the species is well represented in that square.  A study by Thomas and Avery (1995) showed that maps at the 10 km resolution probably reflect real declines in only the rarest species, whereas declines of species of intermediate rarity may be underestimated by as much as 85%, and population losses of common species are unlikely to be detected at all.

One species that is now locally scarce but is not showing range contraction on butterfly atlases is the Small Heath. For species that are declining strongly, like the Wall Brown, the 10 km maps are showing range contractions. For butterflies like the Small Heath and Small Copper, To obtain a clearer reading of the status of butterflies like the Small Heath and Small Copper, maps with a more detailed level of resolution are needed.  If you can help with recording, please send in your records, according to the details here  https://butterflyconservation.ie/wp/records/

Why are declines happening?

Recently, a conservationist who carries out site surveys told me that he is seeing “habitat destruction everywhere” he looked. One does not need to look hard to see this depressing situation. Here are just some examples of habitat destruction and some butterfly losses arising.

These are just a few examples of habitat damage. But there are many more, including around our own homes. Spraying chemicals to control “weeds” create damage, and this anti-social behaviour, while not as conspicuous as industrial-scale pollution and habitat loss, damages ecosystems too and says so much about our attitude to nature. Conservation starts at home. Let us all play our part.

 

Spring has really made its presence felt over the last week, with abundant sunshine bringing nature to life. Birdsong seems constant, with Blackcap, Chiff-chaff, Willow Warbler, Song Thrush pouring their music from scrub and hedges everywhere. The Barn Swallow arrived in early April and the Cuckoo has been heard in Donegal.

The Brimstone is on the wing in its open woods and scrub habitats that contain its breeding plants, Purging Buckthorn and Alder Buckthorn.  Orange-tips, emerging later than in recent years, are now flashing their gleaming, high-vis orange tips in bright sunshine while the less showy females already looking for egg-sites. Green-veined Whites are emerging too-a species to watch, given a recent decline. Large Whites and Small Whites are now hatching from their pupae and exiting the gardens where they pupated last autumn. Speckled Woods are out too-less conspicuous than the whites, but can be seen fluttering around grassy scrub and hedge edges edged with wild grasses.

Holly Blue, a much smaller butterfly than any mentioned so far, is highly prominent because their shining lilac-blue gleams in the sun. This active butterfly loves suburban and urban gardens with holly and ivy, the breeding plants for the first and subsequent generations respectively.

Comma, Peacock and Small Tortoiseshell butterflies are found in and around their Stinging Nettles, the food plant for their caterpillars. Males are quite territorial-while the sexes look identical, males will fly after any object thrown in the air, while the females ignore it.

Spring butterflies are at the mercy of the weather. Spring can collapse into winter very suddenly, and when this happens for a prolonged time, spring can be over for these early season fliers.  In short, enjoy the Orange-tips, Brimstones and the rest of spring’s insects, two of which are featured below, while they are here!

Brutus: There is a tide in the affairs of men.
Which, taken at the flood, leads on to fortune;
Omitted, all the voyage of their life
Is bound in shallows and in miseries.
On such a full sea are we now afloat,
And we must take the current when it serves,
Or lose our ventures.

Julius Caesar, Act 4, Scene 3, 218-224.

An era has ended for Ireland’s state-owned bogs and a new phase is beginning. Bord na Móna’s announcement in late 2020 that all peat cutting has ended on its estate coupled with the Government’s Peatlands Climate Action Scheme (PCAS) announced by the Minister of the Environment, Climate Action and Communications Eamon Ryan on 24 November 2020 marks a new beginning. This Scheme will see the Minister support, via the Climate Action Fund, Bord na Móna in developing a package of measures,  for enhanced decommissioning, rehabilitation and restoration of cutaway peatlands, referred to as the Peatlands Climate Action Scheme.  The additional costs of the scheme to rehabilitate peatlands are being supported by the Government through the Climate Action Fund, administered by the Department of Environment, Climate and Communications (DECC), while the National Parks and Wildlife Service (NPWS) will act as the Scheme regulator. (Details of the scheme can be found here https://www.gov.ie/en/publication/136a7-bord-na-mona-bog-rehabilitation-scheme/)

Before we get too excited, we need to consider the condition, among other important factors, of the peatlands being rehabilitated. Most of the peatland areas selected (and there are many bogs that have not been added to the scheme) are so severely degraded that it is not possible to restore them to anything resembling their once pristine condition. In short, the restoration of “active raised bog” as described by the European Union Habitats’ Directive Annex I   within the foreseeable future is not possible. In fact, the primary objective of the Government scheme is not habitat restoration but to turn carbon-emitting peatlands into carbon sinks to address climate change. This is a worthy objective, especially as the re-wetting is planned to set the peatlands on a trajectory towards the establishment of a mosaic of compatible habitats including wetland, fen, reed swamp, wet woodland, heath, embryonic sphagnum-rich peat-forming communities, scrub and birch woodland communities.

Refinements in the re-wetting measures will be applied where important grassland habitats have developed on parts of the peatlands selected for enhanced decommissioning, rehabilitation and restoration. This is key to protecting important butterfly habitats. Some bogs contain superb grasslands, including orchid-rich grassland one might expect to see in a very different habitat, such as in karst landscape and eskers. Some of the high-quality grasslands are so studded with summer orchids the fragrance is stunning, almost cloying in its concentration. Over this fragrant colour dance bejewelled butterflies like Common Blue, Dark Green Fritillary and Small Copper.

Modern farming has destroyed the vast majority of flower-rich grasslands making the biodiverse grasslands on peat soils the last bastion for many butterflies. Some species that are now unknown from farmland have found refuge in cutaway bogs (peatlands from which most of the peat has been removed).  There is, for example, no known viable population of the Dark Green Fritillary butterfly in County Kildare outside the Ballydermot Bog group area.

This area of bogland currently holds among the best butterfly and moth habitats and populations in Ireland. The area holds 25 butterfly species, some of these endangered, and hundreds of moth species, including endangered species. At around 7,000 hectares, in one large contiguous block, it is the right size for species to move around in the landscape, allowing species to find the best habitats for their needs and avoid genetic bottlenecks which damage a species’ vitality. Butterfly Conservation Ireland’s monitoring of the Marsh Fritillary in the area shows that the species is moving around in the landscape taking advantage of optimum habitat as it develops. We have noted that there is a high level of variability in the wing markings of the Marsh Fritillary butterflies in the region, a clear indication of genetic diversity. In short, the population of this endangered butterfly is healthy here and this must continue.

Once in a Lifetime Opportunity

Peat-cutting has ceased in the state-owned Ballydermot Bog group area. The machinery has fallen silent, and the sounds are now exclusively nature’s voices. Ravens and Whooper Swans in winter, Cuckoos and Willow Warblers and Great-spotted Woodpeckers in spring,  grasslands sizzling with grasshoppers and humming with the drone of bees shouldering their way through flowers in summer, followed by Goldfinches, Linnets and Lesser Redpolls delivering their liquid notes throughout autumn as they pick their way through the rich seed harvest.

Flowers bloom from April to October hosting various butterflies, bees, moths and much more according to the season. Vast native birch woods, shrubbery rich in birds, sky-reflecting lakes, ponds, dry and damp calcareous grassland, wet grassland, heath, fens, bogs abound. There is so much for the nature-lover and rambler to enjoy. The varied landscape gives a restless and artistic eye the drama of change to soothe and inspire. The area offers you the freedom to lose yourself.

And look where the area is, on the doorstep of the biggest population of people in Ireland, a wilderness offering exploration, freedom, health and happiness. I once brought a group of underprivileged urban teenagers to these bogs on a fairly dull spring day. After clambering out of the minibus they looked around, bemused. “Where are the shops?” “Where are the paths and street lights?”

I feared a long, long day. But no. They loved every minute of it. “Are we allowed to go here?”  There are no walls, boundaries or prohibitions to inhibit freedom. Of course, they jumped in every pond, drain and puddle available, amazed at frog spawn and “water lizards” (newts!) Notorious for their boisterous behaviour,  their exuberance was appropriate here, perhaps for the first time.

Why am I telling you this? Because there is so much more to nature and what it has to offer than hitting climate action and Water Framework Directive targets, very important though these things are.  Horse riding, walking, running, cycling, picnicking, scientific study for young and all other age groups are available along with tremendous physical and mental wellbeing benefits. And, perhaps above all, the vastness of the space offers great freedom. And all compatible with habitat restoration and nature conservation.

It is time to show vision, to take the opportunity now available. The west of Ireland has five national parks. There is no national park in Ireland’s midlands.  Without this landscape-scale protection, the long-term viability of many species in the region is in peril.  Butterfly Conservation Ireland, together will all the non-governmental environmental organisations, is calling on the Minister of the Environment, Climate Action and Communications Eamon Ryan, Bord na Móna, Kildare County Council and the National Parks and Wildlife Service to establish a new national park in the Ballydermot Bog group area, for nature, for people, forever.

 

 

In the butterfly world, signs of spring are often well concealed and most of the signs that are detectable are subtle and elusive. The glowing colours of the adult butterfly will only be seen later in the season in the case of most of our species so we must look hard for the signs that are available. Below are some of these signs. Let us imagine how these lead to greater glories as warmth returns.

Ireland’s butterfly species operate in a relatively cool climate which presents challenges to these ectotherms, cold-blooded animals whose regulation of body temperature depends on external sources, such as a cool, shaded woodland or direct sunlight or a heated surface such as a mat of dead vegetation, branch or rock.  The metabolic activity and physical movement of butterflies are highly influenced by the thermal environment. This article looks at strategies butterflies use to deal with their thermal environment.

The adult butterfly needs to fly to escape enemies, to find food, mates and breeding sites. Efficient flight is only possible when the thoracic musculature, which houses the wing muscles, reaches temperatures in the range of 35-40 Celsius. Biological functions, such as mating, egg development and egg-laying, require certain temperatures (these vary according to the species). Air temperatures in Ireland rarely reach the levels needed so how do our butterflies reach the temperatures required for efficient flight and for the metabolic activities needed to sustain life?

During our butterfly flight periods, all our butterflies deal with thermal challenges.  These can be unsuitably hot or unsuitably cool conditions. A way to raise body temperature to enable the butterfly to take flight is wing muscle vibration. This is used by a butterfly during cool weather or when it has roosted in a cool location when it is unable to use external heat sources to warm its flight muscles. Wing muscle vibration, which looks like the butterfly is shivering, allows a butterfly to create enough heat to fly to or from cover but will not allow for sustained flight. The butterfly (or moth) vibrates its wings vigorously until it has created heat by friction that enables it to fly, usually weakly and briefly, to reach a suitable location. In cool, breezy weather this strategy may not work, leaving the immobile butterfly vulnerable to predation and severe weather. Occasionally, early on spring and autumn mornings, stranded butterflies can be found resting in the open on a flower from the day before, covered in dew.

Butterflies are efficient heat seekers, frequenting warm sheltered areas receiving direct sunlight even when these sites contain fewer resources than more open sites. It will be noted that open flower-rich grassland will often have fewer butterflies than expected, while sheltered rides in woodland with fewer nectar resources can hold an abundance of butterflies and other insects. Managers of nature reserves containing open, exposed grassland should be careful to allow some scrub, a resource that enables grassland butterflies to find shelter when the weather is cool, cloudy and windy. When the sun shines, butterflies will move into more open areas. As our climate warms, scrub habitats may become vital for butterflies to escape escalating heat during the hottest times of the day or season.

Butterflies also adopt thermoregulation strategies (regulation of body temperature) that vary according to species, habitat and temperature. The wings are used to regulate temperature, both to raise and reduce the temperature.  Most of our butterflies will bask with wings held wide open when they need to increase body temperature. This is known as dorsal basking. When the thorax is coolest, the wings are held fully extended and the extreme edges of the wings are pressed against the surface, often bare soil or rock. This is known as the ‘appression’ posture, proposed in one study as potentially different from dorsal basking. This is often seen used by the Small Tortoiseshell, Peacock, Comma, Red Admiral and Painted Lady-the first three species use this technique frequently on cool, sunny days in early spring. This technique is believed to be the most efficient for increasing thoracic temperature, by trapping warm air radiating from the surface,  trapping warm air radiating from the underside of the wings and minimising the flow of cooling air around and under the thorax.

Basking with wings held off the surface in a horizontal posture is used to warm the butterfly when it is cool but slightly warmer than a butterfly applying appression.  The butterfly is absorbing heat onto the wings, but experiments with dead butterflies show that only 30% of the wing area closest to the body is used to transfer heat to the thorax.  A heating thorax causes the basking butterfly to angle its wings, forming a shallower ‘V’ as the thoracic temperature rises until the butterfly folds its wings, a posture to allow cooler air to circulate around the thorax so the insect can cool down. If it becomes too warm for this thermoregulation strategy to be efficient, the butterfly seeks shade.

Lateral basking is another thermoregulatory mechanism used by some of our butterflies. This involves basking with folded wings where the butterfly perches on a surface and angles its wing surfaces by leaning sideways onto the sun to receive the maximum solar incidence when the insect is too cool. When the butterfly is warming, it starts to correct its posture until perched upright. When the butterfly is too warm it stands head-on to the sun, raising its body off the surface by standing tall. This strategy is used particularly and rather strikingly by the Graying, and less notably by the Large Heath, Small Heath, Green and Purple Hairstreaks and the Brimstone. The Brimstone uses this especially in spring, typically by basking on dry, dead grass clumps. Using this mechanism, it can raise its body temperature to the high 30s Celsius when air temperatures are barely above 13 Celsius.

The other form of thermoregulation used is called reflectance basking. This is used by some of the whites, especially the Large White, Small White, Green-veined White and Orange-tip, although these species will occasionally use dorsal basking when they need to recover a steep loss of body heat. The butterfly perches on a surface, usually a leaf, with wings half-open. It orients its position to receive sunlight onto its wing surfaces. The white wings reflect solar radiation onto the body to increase body temperature. A dusting of dark scales on the wings near the thorax may also play a role in heating the thoracic muscles. When it is too warm, the butterfly shields body tissues from the sun by folding its wings.

A thermoregulation mechanism used by the Brown Hairstreak to avoid over-heating on its sunny, sheltered hedge habitat is orienting its closed wings towards the sun, where its shiny undersides reflect rather than absorb the light. While this appears to be lateral basking, which is used to increase body temperature, this rare butterfly mainly uses dorsal basking to warm itself. Appearances can deceive!

Let us look at how adult butterflies respond to prolonged unsuitable thermal conditions. Migration involves butterflies leaving an area that is becoming unsuitable and moving to a location where their needs are met. It enables butterflies to escape the onset of prolonged unsuitable conditions typically caused by changing temperatures. An example of this strategy is the migratory habits of the Painted Lady, which extends its range progressively from early spring onwards through summer, from North Africa, throughout Europe. This continues until the onset of cold weather when return southwards migration of the species is undertaken by the children, grandchildren and great-grandchildren of the individuals that dispersed northwards earlier in the year.

Another response by adult butterflies to prolonged unsuitable thermal conditions (in Ireland these prolonged conditions consist of low temperatures) is hibernation. This is used by the Brimstone, Small Tortoiseshell, Comma and Peacock butterflies and by several moths, such as the Red-green Carpet, The Herald and Tissue. These species remain dormant until suitable temperatures return.

The next time you are outside looking at butterflies, look at the posture it is adopting. There is nothing casual, accidental or whimsical about the way butterflies perch, they are always doing what they do for a reason. There is a lesson for us in that, but you can decide what that is!