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The Sark JournalThe butterflies of Sark
A butterfly believed gone for nearly thirty years came back, and the recorders were ready
In May 2025 a Glanville fritillary was seen in a meadow at Vallon d鈥橭r. The species had not been recorded on Sark for nearly thirty years, since about 1997, and was believed extinct on the island. Further sightings followed near La Coupee and in Little Sark, enough to suggest several small colonies rather than a single stray.
A return like that only becomes visible because people kept looking through the years when there was nothing to find. Sark鈥檚 butterflies and moths have been well studied since 1873, when W A Luff found 28 species of butterfly and 48 of moth. In 1970 Roger Long at La Soci茅t茅 Jersiaise listed 57 butterfly species for the entire Channel Islands, 39 of them for Sark, among them the small pearl-bordered fritillary, found only in Sark between 1947 and 1967.
The people behind the records
Regular annual recording has been carried out by Margaret and Roger Long and by the late Michael Shaffer with his wife Dr Monika Shaffer-Fehre, work that has brought the total number of Lepidoptera recorded on Sark to 566, the vast majority moths. Shaffer鈥檚 study Lepidoptera of the Channel Islands was published in 2008, less than a year before his death. The island still keeps resources ready for visiting entomologists: annual lists, field guides, a student microscope and the Heath Actinic Moth Trap donated by Roger Long, for whom it was specially made.
Shaffer summed up what all those records show. The fauna is large enough that live adults can be observed at almost all times of the year. Most species are highly seasonal: a few produce adults in winter to very early spring, others fly only in autumn, and the majority run two or more breeding cycles a year from late spring to late summer. Hibernating adults may fly in warm winter spells, and in warmer weather many breeding species have their numbers vastly boosted by annual migrations between the islands, and especially directly from the Continent.
Where to look
The silver-studded blue is the resident to seek out. It lives on the coastal heathland at L鈥橢perquerie and around the Pilcher Monument, and on 19 July 2024 Andy Smith, Butterfly Conservation鈥檚 County Recorder for Guernsey, Herm and Sark, counted twenty-two in a single survey. It went unrecorded at Hog鈥檚 Back that year.
What an honest bad year looks like
2024 was a poor season, and the records say so plainly. An early, mild February gave way to a cold, wet, windy spring. Insects collected in malaise traps during a very wet July and August were more than 50 percent down on previous years, and the Pollinator Project鈥檚 bee survey struggled to find enough bees to complete its counts. Then October brought a sudden explosion of moths, butterflies, caterpillars, bees and mosquitos.
The butterfly records for that year, surveyed by the same County Recorder with incidental sightings collated by La Soci茅t茅 Sercquaise, work from a checklist of 29 species. Survey visits in April, May and July produced records of 21. Eight checklist species were not seen at all, among them the dark green fritillary on the Gouliot Headland, the green hairstreak, the Queen of Spain fritillary, the Geranium bronze, the clouded yellow, the long-tailed blue and the small tortoiseshell. That is one wet season鈥檚 data, not a set of extinctions. The Glanville fritillary went unrecorded for nearly thirty years and then came back; on Sark, an absence in the list is a question, not a verdict.
New arrivals
The list grows as well as gaps closing. A swallowtail was recorded breeding on Sark for the first time in 2011. Swallowtails have since reached southern England, and June 2025 brought a further influx to the island, with larvae found feeding on garden fennel. The Soci茅t茅鈥檚 other notable records include the survival on Sark of the large tortoiseshell.
Why this matters when you visit
For a visitor, more than 150 years of recording doubles as a field guide. The places in it are named and you can stand in them: the heathland at L鈥橢perquerie and the Pilcher Monument in July for the silver-studded blue, a patch of garden fennel in June where swallowtail larvae have fed, the meadows at Vallon d鈥橭r in May, where a butterfly ended a silence of nearly thirty years.
The season鈥檚 records, species by species, are on the butterflies of Sark page. The Getting to Sark guide covers the journey to the island.
