Why dragonflies are worth learning to recognise

A garden pond is never just a pond. Once dragonflies find it, you have a hunting ground, a nursery and a stage for some of the most watchable behaviour in British wildlife. The trouble is that they move fast, and the three species you are most likely to meet in a garden or local wetland — emperor, common darter and southern hawker — all flash past in a blur of blue, red or green. The trick is to stop chasing them with your eyes and start reading three things instead: markings, flight style and where they choose to land. Get those three habits in your head and identification becomes surprisingly quick.

Emperor dragonfly: the patrolling giant

The emperor is our bulkiest dragonfly, roughly 78mm long, and it rarely sits still. Males are unmistakable in good light: an apple-green thorax and a bright blue abdomen with a bold black stripe running down the middle like a painted seam. Females are green throughout with a brownish tinge. Look for the eyes — green-blue and enormous, dominating the head.

Behaviour gives the emperor away before colour does. Males patrol a stretch of water, often ten to twenty metres of bank, flying low and level with a steady, powerful beat and occasional hovering pauses. Rival males are seen off with spiralling chases that rise high into the air. Emperors seldom perch; if you do find one resting, it will be hanging among reeds or on a tall stem. They are on the wing mainly from June to August, with egg-laying females dipping the tip of the abdomen into submerged weed while a male hovers guard above.

Common darter: the obliging perch-sitter

If a small red dragonfly keeps returning to the same stone, fence rail or bare patch of path, you have almost certainly got a common darter. At around 40mm it is compact and neat, and the males glow brick-red with darker red-brown markings along the abdomen. Females and immature males are a golden yellow-brown.

Two details settle the identification. The legs are black with a fine yellow stripe running down them — the similar ruddy darter has wholly black legs and a more club-shaped abdomen. And the posture is a giveaway: darters sit low and horizontally on warm, flat surfaces, darting out to snatch small flies before returning to the same spot. They are on the wing from July right through to October, sometimes November, which makes them the last dragonfly of the garden year and a fine subject for a sunny afternoon.

Southern hawker: the curious wanderer

Hawkers are the big, dashing dragonflies that never seem to stop. The southern hawker is our most garden-friendly one: dark, with two broad pale green stripes on the sides of the thorax and, in males, blue spots along a black abdomen that ends in a broad blue band on the last two segments. Females carry the same pattern in green.

Watch the flight path. A southern hawker patrols a circuit rather than a line, working along hedges, paths, shrub borders and woodland edge, often well away from water, and it will hover a foot or two from your face to inspect you — an unnerving and rather charming habit. When it rests, it hangs almost vertically from a twig or branch, usually in dappled shade. Look for it from late July to October.

Reading flight, season and perching habits

Use this quick check when something zips past:

• Big, blue and green, flying low and level over open water, never landing: emperor.
• Small, red, repeatedly returning to a low warm perch: common darter.
• Large and dark, looping along hedges and paths, hovering to stare at you: southern hawker.
• Early season (June to August): emperor at peak.
• Late season (August to November): darters and hawkers dominate.
• Perch position: ground and flat surfaces mean darters; hanging vertically in foliage means hawkers.

Making your garden and wetland work for them

Dragonflies are practical creatures, and a few simple features will bring all three species in. Leave a pond with gently sloping, planted margins and no fish, which will eat the larvae. Add native marginal plants, oxygenating weed and a few floating leaves for egg-laying females. Keep a patch of rough, unstrimmed grass and some log or stone piles nearby — these are the basking stations darters adore.

Bare earth and gravel paths, fence posts and warm stones are worth their weight in gold, so resist tidying every corner. Allow pondside plants such as reedmace, iris and water mint to stand through winter, and leave seedheads and stems uncut until late spring, since larvae climb these stems to emerge. Then on a still, warm day between late morning and mid-afternoon, sit downwind of the water and wait. Twenty quiet minutes will teach you more about dragonflies than any book — and once you can tell the patroller from the percher from the wanderer, every pond you pass afterwards will read like a familiar page.