It is hoped that by claiming the Dark Green Fritillary as a Cheshire butterfly this does not contravene the Trade Descriptions Act! The reason for this is that there is no evidence to suggest that this insect has bred in the county for many years. Nevertheless, hardly a year goes by without a sighting somewhere in Cheshire, with the last occasions that there were no reports being in 1998 and 2009.
Back in the mid-1800s the Dark Green Fritillary regularly bred along the Wirral coast in the sandhills between Wallasey and New Brighton, but there are no indications as to when breeding ceased at this locality. A lack of historical data in subsequent years has meant that the only other reports of breeding in the county relate to the mid-1940s when the butterfly was reported from sites in the Delamere and Hartford areas.
In more recent times most years have produced a few sightings, although these have invariably been of single insects which have never lingered at any locality. This elegant butterfly normally stays within its sharply defined colonies, although it is a strong-flying insect which can roam over considerable distances. Nowadays it would seem likely that most reports in the county are of wanderers from breeding colonies in surrounding counties – either along the North Wales coast, the Ainsdale dunes or the Derbyshire Dales. In support of this theory is the fact that most sightings from the eastern half of Cheshire are reported after easterly winds which have presumably swept the butterflies down from their colonies in the Derbyshire Peak District.
Over the past 25 years data from the Cheshire Butterfly Recording Scheme has shown that this insect has been recorded in the county on 41 occasions. It is no coincidence that 46% of these reports have occurred on the Wirral where one would expect the majority of sightings of butterflies that had wandered from coastal breeding sites in the surrounding counties. A further 24% of records have been at localities around the Pennine hills, close to the Derbyshire breeding grounds. The remaining sightings since 1984 have been from widely scattered localities throughout Cheshire.
Nationally, the Dark Green Fritillary is one of our most widespread fritillaries occurring from the Channel Islands to the Outer Hebrides and Orkney, although it is rarely found anywhere in large numbers. As with the other species of fritillary it has declined in many parts of its range, but not as dramatically as some of the UK’s other fritillaries and is still locally abundant in a few regions. It has, however, markedly declined in others, especially central and eastern England. If you are lucky enough to see a large fritillary in Cheshire it will almost certainly be this species – the High Brown Fritillary has not been reliably recorded in the county since 1922, whilst there is just a single recent record of the Silver-washed Fritillary in 1995. In recent years the majority of sightings in Cheshire have been of a fast-flying insect disappearing into the distance, although perched views can sometimes be obtained as it is attracted to nectaring on thistles and knapweeds.
Although it would seem unlikely, it is still possible that the Dark Green Fritillary could breed again in Cheshire. Two of its main foodplants – Common Dog-violet (Viola riviniana) and Marsh Violet (V. palustris) - occur in the county, whilst the butterfly can be found in a range of habitats, but often with a distinctly coastal preference. The insect does, however, thrive in flower-rich grasslands which sadly are nowadays in short supply in Cheshire.
The Dark Green Fritillary is a single brooded insect with adults flying from mid-June to late August, but in Cheshire there is a significant concentration during the last week of July and the first week of August, with 49% of all reported sightings falling within this period. Earliest sighting in the county was at Caldy Nature Park on 12th June 1996; latest at Alderley Park on 24th August 1990.
Written by Barry Shaw for News, the Cheshire and Peak Distrcit Branch of Butterfly Conservation magazine.