My last post concerning the fate of the Grey Partridge was slightly depressing, so I thought I would redress the balance with something positive. It is still a few months before the butterflies start to appear and today is grey and wet. For a ray of sunshine I bring you ….. The rise and rise of Argynnis paphia, the Silver Washed Fritillary.
It was in 2010 when I saw a report of a Silver Washed Fritillary in a North Norfolk wood not too far from home. At the time it was dismissed as someone releasing a captive bred specimen, possibly for a moment of fame, or to fool those who would rush to see such a rarity. Might sound a strange thing to do but people have been doing such things for a couple of hundred years! Indeed the Chalkhill Blues at Warham https://blhphotoblog.wordpress.com/portfolio/iron-age-blues-2017/ , and the Brown Hairstreaks in Ipswich https://blhphotoblog.wordpress.com/portfolio/pipers-vale-brown-hairstreaks/ , are two recent examples.
However this was not the case. The numbers increased and colonies were discovered in other woodlands.
These magnificent butterflies start to appear in July. They are the largest of the British Fritillaries with a 3 inch (75mm) wingspan. The males are a striking bright orange when fresh. They are powerful fliers and will glide for quite some way along a woodland ride, stopping briefly to nectar on bramble flowers. The males can be told apart by the four very prominent raised black veins on the upper forewings. These are called sex brands and release a scent during mating. The females are slightly larger and duller in colour. An unusual feature of the SWF is that a very small percentage of females turn out a fantastic blue/green in colour. These are the Valezinas and sightings are something to cherish.
So why are Silver Washed Frits doing so well when other members of their family i.e the Pearl Bordered and High Brown are disappearing fast? A lot depends on habitat. The latter two require special conditions. Since woodland was left neglected, or worse planted with conifers, they started to die out. They needed areas cleared on a regular basis so they could lay their eggs on violets, the food plant of their caterpillars. The Silver Washed lays its eggs on tree trunks (and my jeans on one occasion!). The caterpillars after hatching descend to the ground to seek out violets. As I said these are powerful fliers and this has enabled the species to spread and colonise and now provide a delightful sight in a high summer woodland.
For a few more images of these butterflies https://blhphotoblog.wordpress.com/portfolio/silver-washed-frits-2017/
Now that’s cheered me up!