Bog Fritillary Boloris eunomia (below) and Marsh Fritillary Euphydryas aurinia (Mike Watson)

Another long-standing dream realised. In the early nineties, when I spent much of my spare time (apart from winter… and even then) watching butterflies, I had a thing about seeing Bog Fritillary Boloris eunomia. There were sites in the Pyrenees that I hoped to visit. I even had Richard Lewington paint the species for me! Well, I can now sit in ‘library corner’ and look at this lovely painting having seen it! I was very lucky to be able to join János Oláh’s inaugural Sakertours Serbia butterfly tour in June and Bog Fritillary was one of three main targets. There were lots of other targets, so it was an opportunity to good to miss and turned out to be one of my all-time favourite tours, even allowing for ‘recentism’.

Bog Fritillary has a wide circumpolar distribution from the boreal zone northwards but only scattered, widely separated colonies south of here. In Europe it occurs from the Pyrenees eastwards to the Balkans with a few colonies in the mountains of southeast Serbia. Bog Fritillary is well-named, occurring in bog side habitats, where its caterpillar food plant bistort occurs. The two colonies we visited were at Babin Zub on the Stara Planina (‘The Old Mountain’). The first was a tiny spring-fed bog with several flourishing stands of bistort Bistorta at 1515m ASL. It was very easy to find the fritillaries at 0700 in the early morning sunshine of 12 June, sometimes flying in the vicinity of Violet Copper Lycaena helle, which often shares the same habitat, a delightful combination. We returned in the evening until 1915 and found several Bog Fritillaries basking in the evening sun. we estimated a total of eight adults at this site [plus six Violet Coppers L. helle]. The row of halos on the underside hindwing is a unique pattern.

The following morning an early start saw us at another colony, a much more extensive bog with a lot more bistort at 1457m ASL, although we only found four Bog Fritillaries B. eunomia until 0800, roughly the same time as out visit to site no. #1. Numbers here dwindled to two the following day, one the next and then none on 16 June. Bog Fritillary is not considered threatened owing to its northern populations, but its southern outposts must surely be threatened by change of land use not to mention climate change and the fact that colonies are widely separated without stepping sone populations to repopulate lost colonies.

BLOG

BOG FRITILLARY