The last Small Pearl-bordered in Botley Wood
Mating pair on Setley Common New Forest
The Small Pearl-Bordered Fritillary in Hampshire
When I joined the Hampshire branch of Butterfly Conservation in 1984 there was still time to see the Small Pearl-Bordered Fritillary at several sites within the borders of Hampshire. 36 years down the road and the species is clinging on to just one site, just within the boundaries of Hampshire and Wiltshire. In a decade or so it’s become increasingly rare and now you have to search very hard to find the species at Tytherley, from what was, one of the best sites to see this butterfly.
Though there is sympathetic management, the site is now so dry it is not really suitable for the species so it will probably disappear from this site in the next couple of seasons. I remember in the 1990’s I had to wear wellington boots when visiting the site as it was extremely wet under foot.
In the late 1980s in Botley Wood, which is one of my local woods, you could see five Fritillaries species flying in the meadows and rides,these were the Pearl Bordered Fritillary, Small Pearl-Bordered Fritillary, Silver-Washed Fritillary, Marsh Fritillary and the Dark Green Fritillary. Sadly now in 2020, we have just the Silver-Washed Fritillary clinging on, and that has shrunk to very low numbers. Unfortunately the area where the Small Pearl-Bordered Fritillary bred many years ago, a small Electricity Power transit station has been built, consequently the last Small-Pearl Bordered Fritillary adult I saw was in 1991.
It was also seen in the New Forest in several locations, but over the years the weather patterns have changed, winters are a lot milder, and the woods have dried out due to lack of sufficient rainfall. The Small Pearl-Bordered Fritillary has a liking for wetter woods, and with the onset of drier conditions the writing was on the wall, however recent winters and early springs have been a lot wetter.
I saw a very small colony in Pamber Forest in 1998 with just two individuals being seen, the site wasn't what I'd describe as arch-typical Small Pearl-Bordered Fritillary habitat probably too small but it was also found on Silchester Common nearby but both colonies were struggling in the 1980's. It is hardly surprising it died out there within another season or two.
Other sites where it could be found were Alice Holt Forest, where it disappeared in the 1980’s as a result of habitat loss and fragmentation. It was also found in the Ashford Hangers area of Hartley Wood, Oakhanger, and even on Noar Hill for a time. Other sites of note were Weston Common near Basingstoke, Ashford Hill NNR near the Berkshire border and Place Wood just north of Portsdown Hill. Small Isolated populations based mainly on the heathland in the New Forest were still to be found into the 1990's. Crockford Stream is one example where it was locally found and widespread like its cousin the Pearl-Bordered Fritillary, also a Holmsley Inclosure where it was seen right up to 2017. However grazing practices in Inclosures like Setley Common and other factors meant it became quite restricted and died out.
Goater in the 1960’s and early 1970’s describes the butterfly as widespread and well established off the central chalk belt in Hampshire and did not warrant naming of specific localities!
How times have changed.
The trend over the past 30-40 odd years seems to be going westward in the country, and the species can still be found in good numbers in Devon, Cornwall, Cumbria, and also in Scotland on the west coast. If one looks at the national situation, this species continues to thrive on the western side of the mainland, particularly in Scotland and can be quite common in some meadows, ironically where the rainfall is high and where most butterfly species find it difficult to cope. It is not that this species is partial to rain, far from it, but the violets on which it depends do like it damp.The butterfly has all but disappeared from the South-East corner of England and we have also lost the butterfly in several isolated colonies on the Isle of Wight at Cranmore and Parkhurst Forest, despite best efforts to maintain the area to its liking.
Unlike its larger cousin the Pearl-bordered Fritillary which requires violet first year plants, this species is dependent on lush clumps of violets which may be found 3-4 years after an area of woodland has been cleared. Otherwise, these clumps may be located on the banks of wet ditches where the soil is crumbly, and where violets may compete and not become swamped by grass species. Add to these requirements the need for sun-exposed areas or at least dappled-shade and it is apparent that most of our dark woods do not pass this test.
However Sussex has bucked the trend and has had a successful ‘re-introduction’ at several localities, and the sites have even had two broods in good seasons.
As with all butterfly species, a sound understanding of its breeding requirements helps us appreciate why a species might struggle. The Small Pearl-bordered Fritillary has been very badly affected by changes in woodland management that has evolved from the 1950's affecting suitable habitat.
Re-introducing the species is probably it's future with re-introductions at sites where coppicing has been undertaken for this and other species but only time will tell for this most beautiful of our Fritillaries.