2025 Butterfly Review

Spring

Several spring butterflies emerged a fortnight or more earlier this year than they did last year. Examples were Wood White on 15 Apr 25 (1 May 24) and Pearl-bordered Fritillary on 17 Apr 25 (5 May 24). Both species did well, being more numerous at most known sites, with further evidence of range expansion for Wood White and very impressive numbers of Pearl-bordered Fritillary surviving the winter on the Malverns, where a long-term reintroduction project is underway. Encouragingly, a single Wood White was recorded in the Wyre Forest for the first time for several years. Most remarkable was the discovery of the first-ever Wood Whites over the border in mid-Wales, where they've spread from Shropshire to several sites along the Kerry Ridgeway.

Our continuing efforts to record Small Blue at new sites around Broadway were not successful and the planted kidney vetch looked badly affected by the drought. A visit to the splendidly named Rattlechain Tip at Tividale in the Black Country, in contrast, proved very productive with many Small Blues seen. The origin of the species at this site is unknown but they've clearly found it to their liking. Unfortunately, the site is threatened by development and there's already been an attempt to destroy its wildlife interest. This backfired: bulldozing areas exposed bare soil that was quickly colonised by kidney vetch and Small Blue. A local resident, supported by Birmingham & Black Country Wildlife Trust, made an excellent presentation at a public enquiry over the summer and we await the Inspector’s report.

Photos:

Wood White at Monkwood on 28 April by Craig Jones

Pearl-bordered Fritillary at Middletown Hill on 11 April by Melvyn Lambert

Early summer

There had been concerns that last year’s poor weather might have a lasting effect on numbers in 2025 but generally these fears were not realised, with some species such as Peacock present in surprisingly good number given how few were seen in autumn 2024. Common Blue showed signs of recovery as did Brown Argus, especially in its second brood later in the year. There were disappointments: Grizzled Skipper was hard to find and not reported from a known site at Throckmorton in Worcestershire; Small Tortoiseshell remained in the doldrums, although up on 2024; numbers of Small Pearl-bordered Fritillary, a species requiring further conservation action, were low for the second year.

Good weather continued through much of May and June and prompted some very early records: Large Heath at Whixall Moss on 20 May, Meadow Brown at Trench Wood on 21 May and Marbled White on 30 May. Early records of butterflies, however, did not always seem to coincide with the flowering of favoured nectar sources and a number of observers remarked on an absence of bugle in the Wyre Forest when Pearl-bordered Fritillaries were on the wing. This was also the case at several sites where Grayling appeared from mid-June, well in advance of its favoured heather plants flowering. An absence of natural nectar sources may be the cause of some of the garden records for the species around Church Stretton. Despite these issues, Grayling did very well at its few remaining sites and seems to be benefiting from management work. There was evidence of dispersal from known sites, with a record from Ragleth Hill and even more surprisingly Venus Pools in late July. One or two other species were seen away from their regular haunts, including a Wall Brown in the Wyre Forest around the same time.

Our use of ultraviolet torches has advanced. Brown Hairstreak larvae were found on three Worcestershire Wildlife Trust reserves; the fact that we found final-instar caterpillars before the end of May suggested an early season and so it proved, with the earliest ever county sighting on 8 Jul. The technique worked for Brimstone caterpillars and Purple Emperor pupae, the latter at both Roundhill and Trench Woods. Purple Emperor can be hard to find in its early stages, although a caterpillar was spotted on Cannock Chase in late April, and UV searches undoubtedly increase our chances. In common with so many other species, adult emergence was early – first seen at Tiddesley Wood on 17 Jun, then Saltwells on 18 Jun and Trench Wood on 19 Jun (including two males around the tops of oak trees in the reserve extension). There were several new records, including a first for Herefordshire, more records from the Black Country and a garden record from near Burton-on-Trent.

The early emergence of so many species had a major impact on this year’s Big Butterfly Count, which took place as usual from 18 Jul to 10 Aug. Many of the species included in the count, such as Meadow Brown, Gatekeeper and Marbled White, had passed their peak; combined with the usual identification problems, we were cautious about drawing too many conclusions from the results. The most numerous species was Large White, followed by Small White; this is usually the case and probably accurate this year, with good numbers of both species over the summer. The Big Butterfly Count is great for getting people involved (record numbers took part this year) but is not a reliable indicator of how butterflies are faring year to year and, with climate change now having a major impact, it may be time to consider its future. It'll be interesting to see what the butterfly transects show when all the data has been analysed.

Photos:

Dingy Skipper at Llanymynech Rocks on 9 April by Roger Littleover

Marbled White at Venus Pool on 2 June by Melvyn Lambert

Late summer

The highlight of August was the discovery of Large Coppers at a site in the Black Country. This species is long extinct in the UK, where it was found in the fenland of East Anglia, and, although undoubtedly an illegal release, its presence attracted considerable interest including that of the national media. People visited from far and wide to take photographs and, interestingly, the butterflies managed to breed on site. Whatever you think of releases, this stunning sight helped promote public awareness of the beauty of butterflies and their need for conservation.

August produced a number of reports of second broods of species that normally have a single generation. Into this category, one would place a sighting of White Admiral at Grafton Wood on 25 August and, even more surprisingly, a Large Heath at Whixall Moss on 5 September. For the first time ever in the West Midlands, there were reports of second-brood Dingy Skipper at both Penny Hill Quarry in Worcestershire and Westwood Quarry in Shropshire in late July, and at Chatterley Whitfield in Staffordshire on 15 August.

Autumn

It's sometimes difficult to tell whether a species has produced an extra generation or whether it is just a case of extended flight seasons in favourable weather conditions but the report of several Holly Blues in September and October, plus a sighting in Worcester as late as 13 November does suggest a third brood. Sightings of species like Meadow Brown, Green-veined White, Speckled Wood, Painted Lady and, of course, Red Admiral in October and November were notable but of particular interest were reports of Clouded Yellow at Grafton Nature Reserve as late as 8 November (reports came from the south coast into December).

Photos:

Large Copper at Bumble Hole on 7 August by Roger Littleover

White Admiral at Monkwood on 16 June by Craig Jones