Regional Species


Marsh Fritillary
Euphydryas aurinia

Photograph by Janet Graham (Morfa Harlech)

Regional Species

This butterfly must once have been fairly common in North Wales but the ever-increasing efficiency of farming methods has led to the destruction of almost all suitable habitat. Forestry and probably development have also taken a toll and it may be that most of the remaining populations are now too small and isolated to be viable in the long term. There are still colonies in Anglesey, the Lleyn Peninsula and several sites further south in Merionethshire. The fact that a previously unknown colony was discovered in 2002 at a coastal site in Merionethshire indicates that, even now, there may still be unknown colonies awaiting discovery. This is a UK BAP ‘priority species’ and is also the subject of a number of LBAPS in North Wales but in spite of this many colonies have no real protection and must still be regarded as threatened. At two small sites in Merionethshire there have been no sightings for several years which is rather worrying.

The requirements of the butterfly are well known and this is a fairly easy habitat to manage or re-create. Basically, the single most important factor is an abundance of Devil’s-bit Scabious (Succisa pratensis), a plant that readily colonises any lightly grazed area without human assistance. Unfortunately, the plant is highly palatable to sheep and can barely survive in sheep grazed areas. Cattle grazing is largely beneficial as the animals neither actively target the plant nor avoid it. However, grazing by horses is best, as these animals actually dislike the plant and this can result in Devil’s-bit Scabious predominating. Of course, ploughing, fertilising or intensive grazing of any sort are all activities that are fatal for the plant and thus the butterfly.

The adults fly from late May to early July. Eggs are laid in large batches (like 'heaped caviar') on leaves of the foodplant with a preference for larger, more vigorous plants. By September the well known larval webs are easy to spot, especially in the morning when they are still covered in dew. The larvae hibernate communally and resume their feeding in the spring when they can again be found on their webs.

This is quite a small butterfly which is often very obliging in allowing the observer to get close so there should be no problems with the identification.