WILLOW EMERALD DAMSELFLY

August 26, 2025

THEY’RE HERE! The colonisation of the UK by Willow Emerald Damselfly | Chalcolestes virids has been just as spectacular as that of Small Red-eyed Damselfly | Erythromma viridulum as they race each other towards Scotland. Willow Emerald now has a foothold in East Lancashire. The first were found by Jen Coates at Lower Towneley Pool in Burnley in 2023 but there were no sightings the following year. However, she did see at least six on 24 August this year at the same spot, which suggests they did breed after all. In the meantime, Allen Holmes found it at another site in Burnley, at Heasandford Lodge.

I had become weary of searching for it without success around Clitheroe so I wanted to see what their habitat was like in Burnley, which might provide some clues to where to look in the Ribble Valley. Allen and I had a great day on his local patch, seeing Willow Emeralds at four sites. We had at least three but maybe as many as six at Heasandford Lodge, including 1-2 mating pairs. Then Allen spotted another at Rowley Lake, in an alder a few metres downstream from the weir. We followed this up with a visit to Lower Towneley Pool where we located one of Jen’s damselflies and then we found it at another new site, Towneley School Pond, in the willows by the pond. The following day John Wright spotted one at another site at Oswaldwhistle where evidence of breeding had been discovered. They have already been busy in East Lancs!

*Willow Emerald Damselfly | Chalcolestes viridis, Heasandford Lodge, 24 August 2025 (Mike Watson)*

I learned from our sightings. Apart from at Towneley School Pond, they were all very conspicuous, perching on the outermost dead branches of trees. They only did this in sunshine. They were using these perches to hunt smaller flies, making upward sallies up from them in a Sympetrum style, often returning to the same perch. Those at Heasandford Lodge and Rowley Lake were in Alders not Willows and the one at Lower Towneley Pool was in an Ash (so no need to focus purely on willows!). At Heasandford and Rowley Lake they were over water (this is also important for their breeding cycle so their larvae fall into water not cold ground). When disturbed they seemed to go upwards in the trees not down (I have seen this before), the mating pairs also did this.

*Willow Emerald Damselfly | Chalcolestes viridis, Rowley Lake, 24 August 2025 (Mike Watson)*

*Willow Emerald Damselfly | Chalcolestes viridis, Townley School Pond, 24 August 2025 (Mike Watson)*

*Willow Emerald habitat at Heasandford Lodge, East Lancashire (Mike Watson)*

*Allen Holmes at Heasandford Lodge, 24 August 2025 (Mike Watson)*

*Towneley School Pond is very dry this year! (Mike Watson)*

*Emerald Damselfly | Lestes sponsa, Heasandford Lodge. At one point flying below the Willow Emeralds (Mike Watson)*

*Black Darter | Sympetrum danae, Heasandford Lodge. Rare to see one in the town, far away from moorland bogs! (Mike Watson)*

*Helophilus trivittatus, Towneley School Pond (Mike Watson)*

*Helophilus hybridus, Heasandford Lodge. A rare wetland hoverfly in East Lancs (Mike Watson)*

*Tachina fera, Rowley Lake - a parasitic fly (Mike Watson)*

*The attractive cranefly Tipula lateralis, Heasandford Lodge (Mike Watson)*

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f.helice!

August 17, 2025

f.helice! How could I possibly follow yesterday’s butterflies? This is how! The first Clouded Yellow near the junction was a white one of the form helice this morning. I had thought why not try and find a helice, as I saw one had been seen in the northeast yesterday? But almost immediately I heard from John Wright that Pete Kinsella had already seen one the day before on Longridge Fell, presumably after we left, so I was hoping it would still be around. I didn’t imagine it would be so easy to find though. Sadly it did not hang around, it disappeared into the plantation to the north at 0955 and was not seen again, despite much searching. There were still at least four other Clouded Yellows present today but there were generally fewer butterflies. However, it was impressive nevertheless with tens of Painted Ladies on the Longridge Riviera. Another fabulous local butterfly watching day!

The only species missing today was Small White. Joined by Phil Larkin and Lee Parnell, my old Ribchester pals, we saw some interesting other things, included a Small Copper probably of an aberration that we haven’t managed to pigeonhole yet as well as the Furry Peat Hoverfly | Sericomyia superbiens (briefly on the same knapweed). There was also a male Black Darter | Sympetrum danae of note, the first I have seen here. There were also a few Tree Pipits around today and other hoverflies included Common Batman Fly | Myathropa florea and Yellow-barred Pond Fly | Sericomyia silentis, two species I am familar with from Grindleton Fell, a few miles to the east.

*Clouded Yellow | Colias crocea - Longridge Fell (Mike Watson)*

*Small Copper | Lycaena phlaeas ab.? - Longridge Fell (Mike Watson)*

*Comma | Polygonia c-album - Longridge Fell (Mike Watson)*

*Southern Hawker (male) | Aeshna cyanea - Longridge Fell (Mike Watson)*

*Black Darter | Sympetrum danae - Longridge Fell (Mike Watson)*

*Furry Peat Hoverfly | Sericomyia superbiens - Longridge Fell (Mike Watson)*

*Yellow-barred Pond Fly | Sericomyia silentis - Longridge Fell (Mike Watson)*

*Common Batman Fly | Myathropa florea - Longridge Fell (Mike Watson)*

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HILLTOPPING!

August 16, 2025

*Clouded Yellow | Colias crocea - Longridge Fell - 16 August 2025 (Mike Watson)*

HILLTOPPING! I knew this was a thing from the continent, associated with mate location and wondered if it might be connected to migration too. Well, I am pretty sure it is. My lunchtime walks up Longridge Fell have regularly included migrant nymphalids like Painted Ladies and whites moving uphill along the forestry tracks but today was something really special. I was hoping to find a Clouded Yellow, with so many reported moving north through the UK at the moment and a late report of one on the fell on 12 August but I wasn’t expecting it to be quite as good as it was on the top of the fell today. The morning started slowly at Salthills Quarry - only two Red Admirals and then at Barrow Lower Lodge - a Small Copper of note, so I wasn’t very hopeful. Walking up the Seven Bends at Longridge Fell was quieter than usual but maybe things had not got going yet as it had been quite cloudy so far. A faded Wall Brown livened things up and then BAM! Clouded Yellow!

I like them because they are very easy to spot! There’s no other butterfly that bright orange-yellow colour in our landscape. It was very mobile flying up and down a very flowery ride between young forestry plantations, the borders of the sandy track rammed with knapweed. After a while following it back and forth it landed a few times, FAB-U-LOUS! The crazy big green eyes, pink legs and the figure of eight on its hindwing! Ooh! There’s another! There were three more and when I retraced my steps back to the spot of the first sighting with Ribchester pal Phil Larkin, we had three together, so that’s six in total at least!

There were so many other butterflies along the quiet forestry tracks today, at one point I counted 50 nymphalids on a 20m stretch of knapweed alone. Lots of Red Admirals and Small Tortoiseshell and smaller numbers of Painted Ladies, Large and Small Whites. There were also residents of the Fell: a single Comma, Green-veined Whites, two Small Coppers, Common Blue, a single Meadow Brown and Speckled Wood and three more lovely Wall Browns! Easily my most exciting day butterflying in East Lancs. 10 species is my benchmark for a good walk and I think 14 must be my highest so far. There were some other good insects today. My first Migrant Hawker of the year was at Barrow Lower Lodge, where there were still at least four Small Red-eyed Damselflies, a late Broad-bodied Chaser, as well as three Brown Hawkers, a couple of Emperors and lots of Common Blue Damselflies. On the fell we saw several Southern Hawkers, including some lovely lime-green females, a Common Darter and a couple of Common Hawkers. However, the best sighting was probably one of the last, Furry Peat Hoverfly | Sericomyia superbiens - an uncommon late-flying carder bee mimic. Thanks to Pete Kinsella for pointing this out to us. What a day today was!

*Wall Brown | Lasiommata megera - Longridge Fell - 16 August 2025 (Mike Watson)*

*Painted Lady | Vanessa cardui - Longridge Fell - 16 August 2025 (Mike Watson)*

*Forest track, Longridge Fell (Mike Watson)*

*Southern Hawker (female) | Aeshna cyanea, Longridge Fell (Mike Watson)*

*Furry Peat Hoverfly | Sericomyia superbiens - a late-flying carder bee mimic (Mike Watson)*

*Migrant Hawker | Aeshna mixta - Barrow Lower Lodge (Mike Watson)*

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LAST OF THE SUMMER BUTTERFLIES

August 10, 2025

*Brown Hairstreak | Thecla betulae (female), Arnside & Silverdale AONB (Mike Watson)*

LAST OF THE SUMMER BUTTERFLIES. The last two single brood butterfly species to emerge are usually Scotch Argus Erebia aethiops and Brown Hairstreak Thecla betulae. The former is easy enough to see, particularly at its mega colony of Smardale Gill, but Brown Hairstreak is not nearly so. It was re-introduced to the Morecambe Bay limestone in, or prior to, 2011 having gone extinct in the Arnside/Silverdale area in the 1930s. This was a private release and I have no idea if it has been supplemented since but it can now be seen with some regularity at several spots here. Just like in its southern haunts, it is particularly fond of Hemp Agrimony nectar, where it can be ridiculously tame.

Scotch Argus Erebia aethiops had already been on the wing for a couple of weeks at Smardale Gill ,where, unlike the suggestions online, it is not in the floral verges of the disused railway line, rather on the steep unimproved alkaline grassland opposite the viaduct itself. It was abundant, I saw around 50 walking across the grassy slope but many were quite worn. It is a 2.5km walk each way from Smardale Hall and I will remember that the northwest facing slope is in shade until late morning. There was not much else here though, just a few tatty Meadow Browns Maniola jurtina and Gatekeepers Pyronia tithonus.

The impressive viaduct has 14 arches and carried the South Durham and Lancashire Union Railway for 101 years until the line’s closure in 1962, one year before the Beeching Report. The trains that crossed it transported coal to the steelworks in Barrow but when they closed there was no longer any need for this route.

*Scotch Argus | Erebia aethiops (Mike Watson)*

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WILLOW EMERALD DAMSELFLY

f.helice!

HILLTOPPING!

LAST OF THE SUMMER BUTTERFLIES