Where are our Butterflies?

Suffering from butterfly deprivation…empty grasslands… I’ve passed several (Buddleia) on my dog walks, but haven’t seen a single butterfly on any of them…A walk from Potter Heigham to Hickling Broad yesterday, limited butterfly activity…Ringlet seen on a transect walk at Foxley yesterday, very little else recorded apart from a few Speckled Woods…Weather has been unkind to us at our last 2 events the Wheatfen Swallowtail Day and Wild About Mannington. A Swallowtail put in a brief appearance at Wheatfen…

Here are a few comments harvested from social media reporting on butterfly populations in England during June 2024.

My experience in Ireland has been empty nettle beds, wingless skies, thin populations of some of our commonest butterflies and peering at the best habitats in Ireland to pick out a flicker of butterfly colour.

The Burren in late June 2024: masses of flowers, but a shortage of butterflies. Photo: J. Harding.

What’s wrong?

Let’s consider the weather. May 2024 was described as the warmest May on record by the Irish Meteorological Service. This surprised me. I wonder if night-time temperatures played a role in this finding. June, however, was described as cool, dry with the temperature below average nearly everywhere. All available sunshine totals were below their long-term average.

It remains cool in early July, with no upturn in temperatures predicted as I write on 5 July. Today we are looking at temperatures between 14 and 17 Celsius.

Is it just a case of below-par weather?

That’s unlikely.

It is certainly correct that our butterflies are strongly influenced by weather conditions with emergence greatly delayed by prolonged cool conditions. The sunny May and June saw the Silver-washed Fritillary begin to emerge on 21 June. We have not recorded it yet (as of 5 July). No new Brimstone has yet been recorded.

However, there appears to be an issue with our Vanessids: Small Tortoiseshell, Comma, Peacock, and Red Admiral. There are very few records of these butterflies this summer, in any life form. Between 16 May and 5 July, we have had four sightings of the Small Tortoiseshell, all singletons. Between 9 May and 5 July, two Commas were seen by Michael Gray on 3 July. We have not had any record of the Peacock since 31 May. Up to 5 July, only 20 Red Admirals have been reported to Butterfly Conservation Ireland’s recording scheme. These species breed on nettles and some parasitoids affect all four species. Has there been a peak in a parasitoid that has reduced populations?  Has there been more than one factor impacting the butterflies?  The wasp Phobocampe confusa for example, parasitises Small Tortoiseshell, Peacock and Red Admiral and probably the Comma.

Few Small Tortoiseshells were seen in June 2024. It typically produces two broods each year. Has it left it too late to create a second brood in 2024?

The cool conditions cannot delay the emergence of these species indefinitely. When they emerge, we might understand the nature of any impacts on their populations. All these species enjoyed abundance in 2023, especially the Small Tortoiseshell and Comma. Perhaps we are seeing a crash in 2024.

A Marsh Fritillary rests after laying an egg batch at Lullybeg Reserve, County Kildare. Photo: J. Harding

When cool conditions occur during a species flight period, such as during the Marsh Fritillary’s flight period in May and June this year, its flight period can extend later into June and into July, as it has in Lullybeg this year. In 2024 the Marsh Fritillary recorded flight period in Lullybeg has extended from 19 May to 3 July. In 2023, when we had a sunny May and June, the butterfly’s flight period was from 16 May to 22 June. In cool weather, the butterfly rests deep in vegetation waiting for suitable weather. Despite being typically short-lived, the adult Marsh Fritillary can sit out cool weather for two weeks, possibly longer, if needed.

A male Dark Green Fritillary. This species was beginning to emerge in late June in the Burren. In my experience dating back 20 years, it was abundant in the region by then. Photo: J. Harding

Most of our butterflies are adapted to cool weather, but the adults thrive in warmer weather allowing them to feed, disperse, find mates and lay their eggs. Prolonged bad weather damages populations which rebound quickly in years with better weather.

Provided we are looking after their homes.

 

Moth Morning Delivers a Century

Our Moth Morning hosted by Philip Strickland was a great success. We had over 100 species and still counting. The rain did not deter the moths, because the temperature was high enough to make them active.

The Swallow-tailed moth is one of the larger moths found in Philip’s grounds.

There were several traps set in different parts of Philip’s grounds. Philip is wilding his four-acre site near Maynooth with very encouraging results. The grounds contain a native hedge over 100 metres long, with hawthorn, Common Hazel, Common Holly, Spindle, and Common Blackthorn, among other native plants. His grassland habitat contains native grasses, especially Sweet Vernal grass, and flora such as Common Sorrel, Cuckooflower, Common Knapweed, and buttercup species. This unspoilt grassland teems with Orange-tip and Green-veined White in spring followed by Meadow Brown and Ringlet while shadier spots are the Speckled Wood zones. Small Tortoiseshell and Red Admiral use his nettles and a closer look might reveal Comma too. Philip’s incipient native woodland which contains Pedunculate Oak of Irish provenance will become an enormous asset to biodiversity as it matures.

Grey Pine Carpet. Photo Philip Strickland.

The grounds are managed in sympathy with nature. No chemicals are applied, and native plants are central to everything Philip is doing. The basic infrastructure of indigenous plants already in situ is being built upon by adding more and gradually removing non-native trees put there by the previous owners.

The results revealed by the moth count on Saturday 29 June underscore the importance of the native planting not only in the 109-plus species found but in the abundance of individuals and the range of habitats and breeding requirements represented. Tree-breeding species, grassland and scrubland breeders were present.

An indication of the variety of moths on offer…

As I write, the micro-moths are still being identified which will push the total up. The colours, shapes and textures offered all of us great pleasure. Green, yellow, red, black, brown, white and various shades and combinations of these hues tantalised and delighted. It is reassuring in an epoch of mass extinction to witness high abundance. Hopeful too, for optimism is needed. Everything cannot be bleak. The simple measures Philip adopted afford vital resources to hard-pressed animals in an intensively farmed region but also pleasure and inspiration.

The Lychnis, which breeds on campions is a scarce moth in Ireland.
Green Arches is a locally common moth in Ireland.

We viewed the moths under cover from the rain which made for comfort and greater attention. The bigger beasts on view included the Elephant Hawkmoth, Swallow-tailed Moth, Light Emerald, the Green, Light and Dark Arches and the Large Yellow Underwing. The medium-sized moths were in great abundance: Clouded Brindle, some quite fresh, Common Emerald, Common White Wave, the descriptively named Spectacle and Dark Spectacle, the sharply-dressed Cinnabar, elegantly gowned White Ermine and its less showy cousin, the Buff Ermine were all in attendance. The Straw Dot, a grassland breeder which hates nitrogen fertiliser, showed in high numbers. What a treat.

Sharp-dressed man! A lovely Cinnabar.

The excitement did not end there. Philip laid on a wonderful refreshment for us in his home. Conversation, frequently contentious and animated, flowed. Mothing is about people too!

Sallow Kitten, another scarce moth we managed to see.

On behalf of Butterfly Conservation Ireland, thank you Philip for allowing us to hold our event at your home. Thanks to everyone who made the morning so enjoyable. The experience was a real pleasure. Our only regret is that it was not much better supported.

Moths come in a range of shapes and sizes: a Pinion-streaked Snout.

All photos J. Harding except where stated otherwise.