On Wednesday there was a flurry of excitement in the Worcestershire Odonutters’ WhatsApp group, after Red-veined Darters were spotted at Ripple, a nearby private gravel extraction site, and Pirton near Croome. On Thursday several people went out looking at both Ripple and Pirton, but found nothing, leaving me glad that I’d stayed home – but then in the evening the best dragon spotter in the County found around twenty, including an ovipositing female, at Clifton Pits, which are on the outer reaches of the Croome estate. By yesterday morning they’d disappeared again – but as I said to R, they are migrants, so maybe the urge to keep moving north just got too strong for them. Still, I kept a keen eye out for them when R and I walked around the main lake at Croome yesterday afternoon, and though I wasn’t surprised not to see any, I’ll admit to being a tiny bit disappointed.
Then yesterday evening came the news that the RVD hunt was back on: the guys at Clifton Pits had reappeared. And this afternoon I got a message from the County Recorder, sweetly suggesting that I might want to get over there and take a look myself. So I went – failing to check the OS map for footpaths before I set out, and in consequence missing the route to the main lake where the Darters have been congregating, but finding four or five males, two of them cooperative, at the smaller north pit.
This was the most posey of the males, and also the most mature, so despite the irritating willow fluff on his wings, I’ve chosen him because he illustrates the species markings well. A male Red-veined Darter looks quite a lot like both our native Common and Ruddy Darters, without being easily mistaken for either. It’s about the same size as a Common Darter, and slightly bigger than a Ruddy, but has an almost straight abdomen, whereas the other two are noticeably waisted. Like the Common Darter it has pale stripes along its legs, and like the Ruddy Darter it has a red face with a black ‘moustache’ marking running down in front of the eyes, but its body colour is a quite distinct pinkish red – paler than the Ruddy Darter and less orange than the Common – and the sides of its thorax appear quite blue, with a single diagonal stripe in pale lemon. The real clincher is the eyes, which are red above but pale blue below – a feature the Red-veined shares with the even rarer Scarlet Darter, but not with either of our native red species. The wings are mostly clear, but with a yellow cloud at the bases, and red veins towards the front and base of each wing; the wing spots are pale, but edged in black. Females are yellow, but again have blue bases to the eyes and a blue-green appearance to the sides of the thorax, and yellow wing veins where those of the males are red.
The Red-veined Darter is common and widespread throughout southern Europe and North Africa, but it’s been a regular summer visitor to southern Britain for many years, and while the British Dragonfly Society – never the most radical of organisations – is still describing it as a “fairly frequent migrant”, there’s increasing evidence that it’s now managing to colonise some warmer southern areas, with larvae surviving milder winters. The current appearance of a group in the Shire, though, is due to a substantial recent wave of migration from Europe, with individuals being recorded over the past week from Norfolk to Pembrokeshire, and as far north as Lancashire and Yorkshire. There have been many sightings of females laying eggs at different sites, and if the weather continues hot these could lead to local emergences at the end of the summer, because larval development in the Red-veined Darter can take place in as little as four or five months. Some sources say that these autumn individuals are most likely to immediately head back southwards, in the same way that the Painted Lady does, but we don’t yet have enough data on this species in the UK to know if this is true or not. It will be very interesting to see which of the currently well-populated “RVD sites” across England and Wales have emergent individuals next spring.
R: L2, C10, D9.
