Identifying Dragonflies and Damselflies at Lakes

Two Families, One Lakeside

Almost everything you see skimming a British lake in summer belongs to one of two groups, and telling them apart is the single fastest way to narrow down what you are looking at. Damselflies and dragonflies are close relatives, but they behave and look quite different once you know what to check.

The easiest field marks are these: at rest, damselflies fold their wings along the body or hold them half-open, while dragonflies hold all four wings out flat, like a tiny aircraft. Damselfly eyes sit apart on either side of the head, giving a dumbbell look; dragonfly eyes are huge and meet in the middle. And damselflies are slender, needle-thin insects, rarely longer than a matchstick, whereas dragonflies are chunky and powerful. Once those three habits are in your head, half the confusion disappears.

Watch the Wings: Patterns That Give the Game Away

Wing detail is where identifications become enjoyable rather than frustrating. Near the tip of each wing sits a small coloured cell called the pterostigma — a diamond or oblong patch that differs in colour and shape between species. On the darker species it can be the clincher.

• Banded demoiselle — the male has a broad smoky blue-black band across each wing, quite unlike anything else at a lake edge. Females have pale greenish wings with a small white false pterostigma.
• Brown hawker — amber-tinted wings, obvious even when it is sailing past at speed.
• Four-spotted chaser — dark patches at the base of the hindwings and dark bases to the forewings, giving the "four spots" of its name.
• Emerald damselfly — sitting with wings half-spread rather than folded, a habit that instantly separates it from other blue-and-green damselflies.

Read the Body: Colour and Markings

The blue damselflies cause most head-scratching, so learn two of them properly. The azure damselfly shows a thin blue stripe on each side of the thorax and, near the base of the abdomen, a small U-shaped or goblet-shaped mark. The common blue damalfly — the one you will see most often over open water — carries two broad black stripes on each side of the thorax and has more extensive blue on the abdomen. If in doubt, look at the thorax stripes first.

The blue-tailed damselfly is far simpler: a mostly black abdomen with one brilliant blue segment near the tip, as if someone dipped the end in paint. Among the dragonflies, males of the broad-bodied chaser are blue with yellow spots along a noticeably flattened abdomen, while females are golden-brown. Common darter males are dull brick-red with yellow flashes on the sides; ruddy darter males are deeper crimson with a slightly club-shaped abdomen and entirely black legs.

Flight Behaviour: How They Move Tells You a Lot

Behaviour is often quicker than binoculars. Damselflies flutter weakly and low, settling frequently on reeds, iris leaves and floating vegetation, usually within a metre of the water. Dragonflies patrol with purpose.

• Emperor dragonfly — a big blue-green male cruising a regular beat along open water, often a metre or two up, rarely settling.
• Southern hawker — bold and inquisitive, frequently hovering close to check you, with green and blue spots on a dark body.
• Four-spotted chaser and broad-bodied chaser — perch on a stem, dart out to snatch prey, and return to the same twig. Superb to watch and easy to follow.
• Common and ruddy darters — low perchers, often on bare paths, stones, fences and warm ground well away from the water's edge.

Temperature matters as much as species. On a cool morning, look for insects basking on sunlit leaves or fence posts; once the day warms, they take to the air. Cloud and breeze shut things down fast.

Lakeside Species Worth Learning First

Lake margins — reeds, sedge, iris, floating lily pads and sheltered bays out of the wind — hold a fairly predictable cast through June to September. Start with the common blue and azure damselflies over open water, the blue-tailed damselfly among emergent plants, and the emerald damselfly in rushy, acidic-edged pools. Add the emperor on big open water, the brown hawker over trees and glades nearby, the four-spotted chaser around boggy corners, and the common darter on almost any warm path. Learn those eight and you will confidently name most of what you see.

Making the Most of a Waterside Walk

Choose a still, warm, sunny day and head out between late morning and mid-afternoon, when insects are most active. Walk slowly with the sun behind you where possible, and stop often — a surprising amount of wildlife turns up because you simply stood still. Close-focus binoculars, the sort that focus down to two metres, are ideal; a monocular works well too. Kneel or sit at the water's edge and watch a single perch for five minutes rather than striding the whole bank.

Take a notebook and jot down date, weather, and what you saw. Records of common species are genuinely useful, so send them to your county dragonfly recorder or local wildlife trust. And remember the quiet rule of lakeside watching: disturb nothing, handle nothing, and the insects will come to you.