26-July Wings of Fire: London’s Dragonfly Identification Guide

The male has bluish eyes and a row of blue spots along his abdomen, whereas the female has yellowish eyes with a row of yellow spots along hers. They are generally seen near open water, including patches of water in parks and gardens. Here they glide with a characteristic burst of wing beats as they turn or loop. You can often see them late on warm evenings and occasionally in numbers if there are swarming ants.

The migrant hawker is smaller and can be quite difficult to separate from the others. It tends to fly higher over the water and especially around midday. It also likes to patrol treetops and woodland glades. It is dark brown rather than the light brown of the brown hawker and the male has more blue on his abdomen. The female is dull green with yellowish green spots. It gets harder as immature adults can be grey or even pale lilac. Migrant hawkers are darker than southern hawkers and less hairy than the hairy hawker Brachytron pratense. Fortunately, these species can be compared in Home Park, Hampton Court where they all occur together.

The last large newcomer this month is the southern hawker Aeshna cyanea, which often gets confused with the emperor, which has already been flying for a month. Luckily, both are common. The aptly named emperor is the most impressive of all our dragonflies. It is huge, looks like a top predator and has a great assurance in its flight. It tirelessly patrols over water, usually from some height, occasionally making dramatic lunges. The male is a brilliant sky blue with an unbroken, strong, black line down its back.

The female has a similar line, but on a more greenish background. The male southern hawker is more greenish and has a blue tail whereas the female is generally more yellow and green than her male counterpart. Southern hawkers also have another habit that marks them out. They particularly like woodland rides where the males have the habit of flying right up to humans as if they were inspecting them. They then disappear, only to reappear again as if they weren’t quite sure and decided to have another look. As they do this, you can sometimes see that their abdomen is slightly curved downwards and you may also hear their wings. Mating of this species takes place in the tops of trees, where they are sometimes noticed in the ‘wheel’ position. This may last up to two hours. In the past, they used to be collected using guns filled with dust shot. There is more confusion telling the common, migrant and hairy hawkers apart. These species are not so blue as the southern hawker and the hairy hawker is again much hairier than the rest. It is just possible the very rare golden-ringed dragonfly Cordulegaster boltonii might also be seen.

They are instantly recognisable by their large size and distinct yellow bands along the length of their black bodies. Their preference for heathland and woodland rides means Wimbledon Common is one of the few places they have been seen.

The smaller, fatter darters that are new this month are the ruddy, common and black darter. Darters haven’t really been seen until now. The black darter Sympetrum danae is the easiest to recognise as it is so small and so dark. The male is almost black with a slight waist and the female is mainly yellow and black without a waist. Both have black legs. Unfortunately, these colours can differ a little in the tendrils i.e. newly emerged adults and also in older individuals. They prefer nutrient-poor pools on acid heathland and so are rare in London. Esher Common and possibly Richmond Park are still places where they may be seen. If encountered, it is worth watching them to see if they go into the ‘obelisk’ position. This is when they point their abdomens vertically towards the sun to avoid overheating on hot days.

The common and ruddy darter are much more easily confused. Both are very common, but the male common darter is slightly bigger and has more parallel sides than the waisted ruddy darter. As its name suggests, the ruddy darter is redder. It is a bright crimson red compared with the more orange-red of the male common darter.

Once again, the females are even harder to separate. They are both a dull brownish-yellow and both have black legs; the only difference is in their forearms. These are yellow in the female common darter and black in the female ruddy darter. They also both like a range of habitats, most especially well-vegetated ponds such as those in Richmond Park. Like all darters, both these species are restless and like to perch a lot. Common darters will even perch on the ground in cool weather. If a male alights on a female in such a situation, some ‘rocking action’ is often observed.

There is also a red-veined darter which, although very rare, has been recorded on Wimbledon Common. The male is easily distinguished by the red veining on the leading edge of its forewings and the yellow basal spot on each of her hindwings. The female is equally noticeable with some yellow veining on the leading edge of her forewings and, once again, yellow basal spots on her hindwings.

Lastly, there are the damselflies. The new ones this month are the emerald, scarce emerald and small red-eyed. These join the large red, azure, common blue, blue-tailed, red-eyed and white-legged, all of which are still flying from last month. The small red-eyed Erythromma viridulum arrived in 1999 and was originally only found on just two sites in east London. Now it is widespread. In the male, not surprisingly, it is its smaller size and exceptionally bright red eyes that distinguish it from the other male red-eyed damselfly. Similarly the smaller size of the female small red-eyed damselfly is also helpful in separating her from the female red-eyed damselfly. Cornmill meadows and Esher Common are both places where these confusing species fly together and so can be more easily compared.

There could also be more trouble in separating the emeralds from scarce emeralds. Fortunately, in our area, scarce emeralds prefer coastal ditches and so are only likely to be seen in places such Rainham or Wennington marshes, whereas emeralds are more widespread. Male emeralds are a brilliant, metallic green with a blue tail and blue eyes.

The females are a duller green, without the blue tail and have green eyes. Any confusion with emerald demoiselles can also be helped again by habitat preference as emeralds prefer still water whereas emerald demoiselles are nearly always seen over running water.