Dragonflies

- Southern Hawker dragonfly. Photo: Kevin Baker

Description/identification

More are likely to be added to the list as more people watch out for dragonflies, and become skilled at recognising unusual visitors; and as the climate continues to warm and species known only on the continent spread across the English Channel.

Dragonflies are so popular that they have both excellent field identification guides and a society for dragonfly lovers: the British Dragonfly Society.

Dragonflies are quick to colonise new ponds, and are usually present in all good wildlife ponds. Contrary to advice sometimes given, the widespread dragonflies are at home in very shallow ponds and some species, such as the Broad-bodies Chaser, a frequent garden pond inhabitant, can tolerate periods of drying-out provided they can keep moist amongst leaves, plants or under dead wood. There are also some ‘temporary pond’ damselflies which you might be lucky enough to attract to your pond if it is really well-designed.

Which dragonflies will you find in your pond?

Usually the first dragonflies to come to a new garden pond, at least in the southern half of Britain, are species like the Common Darter or the Broad-bodied Chaser that like bare sediments. Amongst underwater plants you may find the larvae of Emperor dragonflies. In shady, silty and overgrown ponds you often find Brown and Southern Hawker dragonflies.

It is sometimes said that ponds need to be at least 4 square metres (i.e. 2 m x 2 m) in area for dragonflies, and at least 60 cm deep, though neither of these suggestions is really true. Observers from the Big Pond Dip reported finding dragonfly larvae in a quarter of ponds of less than 1 m x 1 m in area (i.e. no more than 1 square metre). All other things being equal, more species will be found in bigger ponds. However, in one good quality garden pond of just 2 m x 3 m, four species of dragonflies were recorded breeding which is more than the average for (much larger) ponds in countryside as a whole. This was because the small garden pond provided an unpolluted, clean water, habitat, whereas most ponds in the countryside are damaged by pollution.

Encouraging dragonflies to your pond

Getting dragonflies to come to a pond is easy: almost any water-filled hole will attract the adults, if only briefly. However, to ensure that eggs are laid and larvae survive to grow and emerge there are several things you can do to help.

First, unpolluted water will help ensure that the habitat overall is as good as it can be, although dragonflies do tolerate some pollution. Second: avoid making the pond too deep: in particular it is important to make sure that the pond is not to deep in proportion to its area, for example in a 2 m x 2 m square pond it is undesirable to make the pond more than 30 cm deep. Deeper water is not particularly needed by dragonflies which mostly live in the shallows. Provide plenty of cover: dead wood for egg-laying Southern Hawkers is a good idea, and sand and gravel to encourage the species that lay their eggs of bare sediment. Clean water will allow the water plants to submerged plants to grow that provide habitat for Emperor dragonfly larvae.

Although, almost all our common dragonflies can be found in garden ponds, at the present time none of the more selective species – especially those more associated with acid water in heathlands and moorlands, or those from lowland marshes – have been reported in gardens. However, it’s an exciting challenge for people lucky enough to live close to such areas to see whether these more demanding species could be attracted to specially-designed garden ponds. In these places providing really clean, shallow, water over natural sand and gravel substrates and thick with mosses and other water plants might be rewarded by some unexpected visitors. If you live near to moorland or heathland, an acid–water garden pond would be well-worth trying. The most likely candidates for this kind of garden habitat creation would be species such as the Downy Emerald, Hairy Dragonfly and Keeled Skimmer.