THE DOWNY EMERALD DRAGONFLY IN CUMBRIA
- We are fortunate in Cumbria to have a few reasonably strong populations of the scarce Downy Emerald dragonfly. Most English colonies are found in the south-east from Dorset to Kent. Otherwise the strongest populations are in Glen Affric in Scotland or Killarney in Ireland.
- In the South-east of England typical habitat is found on ponds and lakes on large country estates. In Cumbria it is associated with tarns in old woodland. Indeed, the species probably occupies some of the most beautiful sites that you could hope to find for a spot of dragonfly watching (see above and below)!
- As one of the early species, the Downy Emerald is usually on the wing in Cumbria from mid-May. Apart from the damselflies, the most likely species to be around at this time is the Four-spotted Chaser.
- It’s not the easiest of species to identify as it rarely comes to rest in accessible places and identification in flight is the only way. It is most likely to be encountered in ones and twos at the tarn edges as a medium sized, bronze coloured dragonfly. Males patrol in a low fast flight, pausing to hover at intervals. As the species turns towards you the most striking feature can become apparent….the bright green eyes. A pair of binoculars will help with this feature, but are of little use in picking out the hairy abdomen from which the species gets its name. Even less likely to be visible is the yoga-like way it places its front legs behind its head when hovering!
- After emerging from the larval state the species spends ten days or so maturing in the woodland before returning to water. Even then, males spend much of their time feeding and resting in trees, only visiting the waters edge for 30 minute spells to look for a mating opportunity. In this way the best sunny inlets are used on a time-share basis by several males. Females are more likely to be seen ovipositing early and late in the day, thereby evading the attentions of the males.
- The key habitat requirement for the species seems to be undecomposed leaf litter (the larva of other species prefer more fibrous, decomposed, muddy litter or growing vegetation). Oak and Beech, which are so typical of Lakeland woods, are notoriously slow to decompose and may help the species to survive here. The larvae are amongst the slowest of all dragonflies to develop, taking three years or more to reach maturity in the south. In the colder waters of the Lake District it is possible that they may take even longer.