Ruddy Darter and Common Darter

Common Darter or Ruddy Darter? Sympetrum is a genus of small to medium sized dragonflies of which there are about 50 species living in the temperate zones of the northern hemisphere. Two of the genus – Ruddy Darter (Sympetrum sanguineum) and Common Darter (Sympetrum striolatum) – breed at Marsh Lane. These two species share the same habitats at Marsh Lane and their flights periods overlap. Similarities in appearance cause some identification confusion but there are clear pointers in the detail of each species that will enable separation. Common Darter is, as its name suggests, one of the most common dragonflies in Europe. They are abundant in England, Wales and Ireland, less so in Scotland. At the start of their flight period – around mid June - a walk around the edge of Dragonfly Pool will put up a couple of dozen newly emerged Common Darters. Towards the end of the summer Common Darters seem to be everywhere, with a few still on the wing at the start of November. Ruddy Darter is found in the temperate regions of Europe as far east as Siberia and as far south as the northern Sahara. Its conservation status is secure, and UK numbers seem to be increasing in some locations such as central England. It prefers quiet bodies of water that feature semi- aquatic vegetation such as rushes and reeds. Ruddy Darter are found across Marsh Lane reserve – around the car park, the causeway, and dragonfly pool in particular - but sightings are very low in comparison with Common Darter. As an indicator you may see no more than ten (if you’re lucky!) Ruddy Darters – male and female – over the whole flight period (early June to early October). There’s probably many more – but they’re elusive and may remain in the reeds around the fringes of the pools. Comparing: The females of both species are very similar. Both are ochre yellow in colouring. The Common Darter is slightly larger but this is only useful if the two species are viewed together. Really the only way to separate female Common and Ruddy Darters is to look at the legs, which will mean close examination. Common Darter has a yellow line running along the outside edge of the legs, whereas the Ruddy Darter’s legs are all black. As the females of each species reach the end of their lives both take on some of the reddish colouring of the males. Whilst the males of both species have differences in colouring, shape and size – the Common Darter is slightly longer – care still needs to be taken to differentiate the two, particularly towards the end of the Common Darter’s flight season. Both species start off in the ochre yellow colouring of the female, but the male Ruddy Darter soon takes on a red colouring. As it matures the colouring becomes a deep blood red. As the male Common Darter matures it also takes on a red colouring but never quite reaches the deep red of the Ruddy Darter. As in the females the legs are a good species indicator – the same yellow line runs down the outside edge of the male Common Darter’s legs – although in very mature specimens this may not be clearly visible; the Ruddy Darter’s are all black. Again close, careful examination is needed. Viewed from above the Ruddy Darter’s body has a club-like appearance. The Common Darter’s body has only slight narrowing. Neither female has such narrowing of the body. The thorax of the Common Darter has two yellow panels; the Ruddy Darter’s is an unmarked reddish/brown – see images below. There are far more Common Darters than Ruddy Darters on show at Marsh Lane. If you see a red or yellow small to medium sized dragonfly at the height of summer presume it’s a Common Darter unless you can see the differences shown above. Of course there’s a very slim chance that you’ve found a migrant Red-veined Darter, a vagrant Black Darter, or something equally exotic! .

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