Cold June reduces Butterfly Count.

As I write this on the grey, rainy Sunday afternoon of June 23rd 2019, a pause to assess the state of the summer so far brings the impression that we are having a really thin time. My impressions are that there are far fewer butterflies out there than we had in June 2018. I have seen less than ten Meadow Browns in my travels, and I have searched sites in a range of habitats and locations-on the Dublin coast (where I drew a blank), in south Wicklow (another blank), Carlow (four), Meath (three) and Kildare (three). But perhaps that is not broadly reflective? To obtain a better impression of how populations are doing, I took four species, Cryptic Wood White, Marsh Fritillary, Meadow Brown and Small Heath, all of which fly during June, to see their abundance levels from June 1st-June 23rd 2019 compared with the same period in 2018.

Cryptic Wood White appears to be on the rise in Ireland. It appears to be everywhere that suitable habitat exists, tall, herb-rich grassy areas with scrub containing any of its larval foodplants. In June 2018, 88 butterflies were notified to the Butterfly Conservation Ireland Records Page. In June 2019 we have received 42 records of this dainty butterfly.  It is down by over 52%.

The Marsh Fritillary enjoyed extraordinary abundance in 2018 and used the prolonged heat well by expanding its distribution by occupying new areas.  We received records of 698 individuals in 2018 but only 245 this year. This is a drop of 64.8%.

The Meadow Brown is probably Ireland’s most abundant species. From June 1st to June 23rd 2018 72 were reported. This June only 14 were notified. This species is down by over 80%.

Small Heath, a small member of the ‘brown’ family of butterflies appears to have been abundant in 2018 with 260 seen. This year 180 were reported, a fall of 30.7%.

While most of the summer of 2019 lies in the future, the start has not been good for butterflies. On many days temperatures have been too low for activity so that adult butterflies remain hidden. Cool temperatures may mean that larval and pupal stages are prolonged. This prolongation may result in higher losses from predators and diseases. Bad weather, especially rain, kills pupae and may harm other life stages.  Good quality habitats buffer species against these challenges. Sub-optimal habitats may be less effective in protecting species from adverse weather, resulting in population decline or loss from such areas, especially of specialists like the Marsh Fritillary.

There are likely to be other factors reducing the numbers being seen. Drought during 2018’s long hot summer damaged larval foodplants especially on open, dry, well-drained habitats like coastal dunes and grassland, dry grassland inland and on limestone and eskers. Butterflies that breed on these habitats are likely to sustain losses resulting in lower abundance in the following years.  This was observed at Portrane, County Dublin, in the case of the Small Blue. Significant damage was in evidence at Portrane in June 2018 with much of the Small Blue’s sole foodplant, Kidney Vetch, destroyed by the drought and extreme heat. In June 2018 I saw two females Small Blues at Portrane lay on the same inflorescence at the same time, behaviour I have never seen before. This butterfly takes great care to avoid laying on a flower that holds an egg for the larva is cannibalistic. On that day, I counted over 400 adults. Last week I counted just four. While shifting sand at Portrane may have contributed to the butterfly’s reduction there, it is inevitable that massive foodplant loss played its part.

There is some very positive news for the Small Blue along the Meath coastline. The Small Blue was introduced there in 2014. The individuals that were introduced were taken from Portrane. Now it is thriving in Meath where it has occupied the entire four km of dunes. There the dunes are more stable and better vegetated, less vulnerable to drought. The foodplant was not destroyed on these dunes. More than fifty were counted last week. If the colony at Portrane ever fails, the Meath colony can return the favour!

A Small Blue at Portrane. In 2019 it is struggling at Portrane but thriving along the Meath coastline. © J. Harding.

New moth record for Louth

The fascinating and surely one of the greatest mimics in the moth world, the Narrow-bordered Bee Hawkmoth has been found in the Cooley Mountains by Enda Flynn and his son Ciaran, both keen observers of butterfly and moth populations in their area. The moth was observed feeding on lousewort, probably Common Lousewort Pedicularis sylvatica. This moth is rare in the east of Ireland, currently unknown in Meath, Dublin, Wicklow, Wexford, Carlow, Kilkenny, Laois and until now, Louth. The number of observers in Dublin, Wicklow and Wexford is high so it is unlikely to have been missed, as it is a large, bumblebee-sized day-flying moth.

The benefits of close observation have paid off in the case of County Louth. If you see this lovely moth, which flies in April, May and June we’d love to hear from you. Let us know where and when you saw it by contacting us at conservation.butterfly@gmail.com.

Here are some photos of the moth.

Narrow-bordered Bee Hawk-moth on the larval foodplant, Devil’s-bit Scabious.© J. Harding. 
Narrow-bordered Bee Hawkmoth.© J. Harding.
This Narrow-bordered Bee Hawk-moth larva is off to seek a pupation site. It will fly next year, most likely during May 2020. There is another form of the larva that has purple markings on its subdorsal and lateral surfaces. © J. Harding.

A Day in the Life of a Butterfly

Some adult butterflies enjoy what is for insects a long life. Peacock, Comma (over-wintering generation), Small Tortoiseshell (over-wintering generation) and Brimstone live long adult lives. Many other butterflies live around a month.

Some butterflies do not have this longevity. They must grab every moment of warmth to feed, mate and lay eggs. One short-lived butterfly is the Marsh Fritillary butterfly, a highly localised species. It has, for example, just one known breeding site in County Dublin. I spent Sunday afternoon on June 9th  observing the colony watching it avail of the sunny conditions to breed. In the next day or so, many of the butterflies you see below will be dead.

The first priority of the male is to warm up in the morning sun. Both sexes bask with wings fully extended, usually on dry grass. It takes a while for the butterfly to absorb the heat it needs making it fairly easy to approach. When warm enough the male embarks on his search for an unmated female, quartering low over the turf. These searches are punctuated by pit-stops for refuelling at buttercups, tormentil, orchids or any flower available. Males frequently clash, and a posse of four or more chasing each other is a common sight on well-populated areas. Sometimes the male will adopt a sit and watch strategy, perching on a taller piece of vegetation until a butterfly appears. He then dashes out to check who it is. It could be a female.

The newly-emerged female Marsh Fritillary frequently sits on the surface close to where she hatched and wait to be discovered by a male. Only rarely will a virgin female fly, and then only when conditions are very warm. The reason for this lack of activity is her weight. A newly hatched female is packed with hundreds of developed eggs, weighing her down. As a short-lived species, it is vital that the eggs are laid as quickly as possible. But for that to happen she needs to mate.

When found, she makes no attempt, like the female Peacock or Small Tortoiseshell at playing “hard to get”. The females of these two species put males through their paces, flying at bursts of speed to see if he can keep up. They even try to shake her suitor off by hiding and by flying directly into the territory of other males who attack him or join the chase!  Nothing like a choice of mates and healthy competition for these females!

Our female Marsh Fritillary has no time for games. She succumbs immediately. After being joined for perhaps 45 minutes, mating is complete. However, to make sure she remains mated only by him, the male seals her to prevent a future mating.

Heavily weighed down, she flutters short distances to seek a good place for her eggs. In cooler weather, she will crawl over the vegetation to search for an egg-site. Finally, she finds a suitable Devil’s-bit Scabious leaf, usually surrounded by well-developed tufted grasses that contain dry leaf litter. The foodplant will be unshaded and often south-facing. Gripping the edge of the leaf, she curls her abdomen to the underside of the leaf and lays her eggs on one side of the leaf, left or right of the mid-rib. It takes her the best part of an hour to glue her eggs on the leaf and onto eggs she laid earlier.

When done, her body looks like a flabby bag. But she is much lighter having laid, typically, 200-300  eggs. She can now fly properly, is much more agile, She visits flowers, repels male attention and basks. If the weather is hot, she may leave her colony to seek new breeding territory. If she is lucky, she will live long enough to develop more eggs, which are fertilised by the sperm she obtained when she mated. Her second or even third egg batch will be smaller than her first.

As for the male, he will continue to look for newly emerged females. He has many hazards-dragonflies, birds, spiders and bad weather account for those unaccounted for by old age.

The Marsh Fritillary lives its short life on exposed grasslands of various types and is therefore vulnerable to bad weather during its flight period in May and June. But every year, enough of them manage to seize that one good weather day to lay down the next generation. As long as we protect its habitats, this lovely butterfly will continue its battle with its short adult life-span, fierce Irish weather and the range of predators that teem on its species-rich homes.

This male Marsh Fritillary is basking to heat up. © J. Harding.
A pair of Marsh Fritillaries mating. The male is on the left. © J. Harding.
This mated female is basking on a Devil’s-bit Scabious leaf. Her abdomen is swollen with hundreds of eggs. © J. Harding.
This female Marsh Fritillary is laying her eggs mass on the underside of a Devil’s-bit Scabious leaf. Interestingly, she is laying on a leaf that was fed on by the larvae a few weeks before. © J. Harding.

Event Report: Outing to Clongawny, Westmeath

Clongawny is just outside Mullingar, not far from the N4. The visited sites lie north and south of the Royal Canal and are quite different. One is calcareous grassland on the steep bank above the canal while the other is a low-lying area of wet, boggy grassland.

We met at the car park near the high bank and set off for the damp grassland first; it is very exposed offering no shelter against the expected rain shower. We needed to catch the sun while we had it. The site was discovered to hold a large Marsh Fritillary colony two years ago. Local Butterfly Conservation Ireland members Lesley Whiteside and Richella Duggan monitor the site. Some scrub was cut and an invasive grass, Reed Canary-grass, was mechanically controlled. Waterways Ireland were notified and an agreement reached that the site’s main nectar resource area would not be mown during the Marsh Fritillary flight period.

In 1902 an observer named Middleton reported a Marsh Fritillary population explosion in the Mullingar area. The general landscape has greatly changed since those heady days but we were keen to see how the present-day population is faring.

The site certainly does not have the look of a classic Marsh Fritillary site.  Most colonies breed on areas where the Devil’s-bit Scabious, the larval foodplant, is very visible as well as abundant. However, even when standing on the site it is hard to see the Devil’s-bit Scabious. The most obvious characteristic of the site is the dominance of rank grasses.  It is only in late summer when the scabious is in bloom that the extent of its abundance becomes clear. The site does have a southerly aspect, a characteristic that is frequently important for the butterfly.

Our group consisted of around 20 people ranging from the very young to the young at heart-great to see interest in nature shared across the demographic! We walked on the main track through the site and Marsh Fritillaries soon zoomed in-and-out- of view.  Males are tricky to follow in flight as they are very active in the sunshine, darting erratically across the grassland, plummeting when a stiff blast of blustery wind pushes it back. Fortune favoured close inspection-the sun was intermittent causing males to land and bask on vegetation. Phones, as well as cameras, were used to take photographs. Some butterflies quietly perched on hands when encouraged, offering great close-ups of this highly local species. A few Cryptic Wood Whites fluttered laboriously around the site, occasionally pestered by urgent fritillaries.  There was not much in flower for the butterflies to feed on. A few tiny tormentils, buttercups and a few clumps of Kingcup (the first time I’ve seen this fritillary use the plant) were really all there was but the butterflies were active regardless.

After we walked the site, we rejoined the towpath and continued east for around 150 metres and entered the edge of the local bog. Here there is a transition zone between raised bog and damp grassland that contains an obvious abundance of Devil’s-bit Scabious and, in the driest areas, Common Bird’s-foot-trefoil.  Patches of scrub provide shelter. A really dense colony of Marsh Fritillary was found here. Common Blue, Burnet Companion moth and Common Heath were recorded too. The frenetic activity of the Marsh Fritillary here created great interest and it is a lovely and interesting area to linger at.

But we re-traced our steps to get our lunch. Lesley’s delicious cookies were delicious! Hot tea and cookies fortified us for the high bank which is awash with vetches, trefoil, hawkbits, orchids and in parts, Kidney Vetch, a rare plant in this area. The sunny track here is great for Dingy Skipper, Common Blue and Cryptic Wood White. We enjoyed watching a lovely ‘blue’ female lay on Common Bird’s-foot-trefoil before darting decisively down the track to seek, no doubt, fresh breeding ground.

We then headed home, happy that the Marsh Fritillary is still in the Mullingar area 117 years after it was reported as a local plague! It is very unlikely we will ever see mass populations again given the damage done to the natural landscape but at least we know where to find the species, and we have local people who care for the butterfly and take the steps needed to keep the butterfly happy.

A special thanks to the event organisers and everyone who came to the event, and in particular to the Baltrasna Environmental Group who take such care of and pride in their wild places.

Freshly emerged Marsh Fritillary at Clongawny. Most of the specimens were small but some more typical specimens were observed. © J. Harding.
Common Blue female; this beautiful blue form (many females are mainly brown with a dusting of blue in the basal area of their upper wings) occurs at Clongawny. © J. Harding.
Male Common Blue. © J. Harding.
Exploring Clongawny Marsh Fritillary country.
Photo J. Harding.

 

Summer Glory

“All the bright precious things fade so fast. And they don’t come back”. (Baz Luhrmann: The Great Gatsby 2013)

One of the sweetest pleasures of the butterfly lover is to see a perfect, freshly emerged butterfly. When it pushes its way out of its chrysalis and dries and expands its wings, the new butterfly perches in the open. Most butterflies then bask, with wings open, to warm up. If you are lucky, you can see these brand new insects, showing perfection to the sun.

This butterfly has yet to have any of its silken glow tarnished. It has not brushed up against vegetation. It has not pursued or been chased by a mate. It has not had its colours bleached by the sun.  He has yet to fight another male to hold a territory. She has not yet lost wing scales crawling around larval host plants to seek out a suitable egg site. No bird has taken a peck at a wing, no dragonfly assault has torn a wing.  No sharp gust has attacked, no rain has pelted at its colour of the perfection of the wing margin. The delicately scalloped wing edge, the outer hair fringe-all breathtakingly pristine.

But life does not stay still for anyone and for a brief butterfly life to have meaning the butterfly must take to her air and fulfil its destiny. He is born to find as many mates as he can. She is born to lay as many eggs as she can in the best places she can find. She will not lay on just any food plants, she is choosy, selecting only the best plants in the choicest locations. She will test the site around the host plant, she may check it to make sure no-one else has laid eggs there before her. She tests the temperature and nutritional quality of the plant.

These activities remove the delicate scales and fray the wing edges. Mindful of this damage, many butterfly collectors bred specimens in captivity to obtain perfect specimens, quickly killing the newly emerged butterfly before it loses any of its perfection. Even in butterflies that are long-lived, such as the Peacock butterfly, which can live ten months or occasionally a month more,  the intense, sharp definition and colour pales quickly. Colour washes out; the deep mahogany-red ground colour of the upper sides dulls quickly. Tiny scars appear. It loses that ‘wow’ factor.

Short-lived butterflies, such as the Marsh Fritillary, which has one of the shortest adult life-spans of any of our butterflies, is elaborately patterned. The brick-reds, creams, yellows are set in various shapes on a dark background. On the more extreme examples, the ground colour is coal black. This enhances the contrast with the bright colours, giving a stronger definition. Within a day, scale loss gives this butterfly a greasy look, a mockery of its pristine glory. It spent around 6 weeks as an egg, ten arduous months as a caterpillar and two weeks as a chrysalis to reach its ultimate state just to lose its glory after the first day as a winged insect.

As a metaphor for human life, the message is clear. Our fate reflected in a butterfly’s, even though it is played out over a longer time. However, we live in an era of greatly increased longevity compared with a century ago. So perhaps we appreciate the beauty of a newly hatched butterfly not just for the extravagant colours and patterns but also for the ephemerality of the display. We sadly have another reason to appreciate beauty today-rarity. Many species are much less likely to be seen today-partly because we have grown distant from nature but also because of the retreat of butterflies underway in the modern landscape.  As early as the 1930s Frederick Frohawk, one of the greatest of the English lepidopterists, warned that the countryside in England was becoming less accommodating to butterflies. Frowhawk died in 1946, before the post-war onslaught of chemical inputs in agriculture. He would be appalled if he could see the British countryside today.

We don’t need to go back that far in Ireland. The changes since 1980 have been immense. Large areas of the landscape have simply been destroyed. And many of these changes are irreversible. Large areas of the Burren (though thankfully, most of it remains) have been destroyed. Most of our raised bogs are extinct. Most semi-natural grassland has been obliterated by ploughing, re-seeding, the input of fertilisers, pesticides and herbicides, drainage, abandonment, construction, afforestation, quarrying, over-grazing, etc.

It is not sustainable to live the way we are, so far from nature that we feel immune to change. What has happened to our butterflies may one day happen to us. That metaphor may be more meaningful than we want it to be.

We have seen a large surge in the membership of Butterfly Conservation Ireland in the last two years. We are a voice to express your love of and concern for our wild places and the wild creatures that rely on these places. Please continue your support for Butterfly Conservation Ireland so that we can continue to demand that our landscape is respected. Otherwise, the beauty of the sensitive species like the Marsh Fritillary, and what it has to teach us about ourselves and the quality of our environment, may not be there to delight and intrigue.

Marsh Fritillary, Kildare. © J. Harding. The Marsh Fritillary population in Ireland is genetically distinct from populations found in Britain and Europe.
Marsh Fritillary underside, Kildare. © J. Harding.