Why a garden pond pulls in dragonflies

Of all the wildlife a small garden can offer, dragonflies are among the most rewarding and the most overlooked. They are not just passing visitors. A pond gives them somewhere to breed, and the larvae — the nymphs — live underwater for anywhere between a few months and several years before they climb out of the water to emerge as adults.

You do not need a large pond. A sunken barrel, a lined hollow of two or three square metres, or a well-planted old sink will all be found, often within a season or two. What matters is sun, still air and plants, not size.

Before you start, learn the two families apart. Dragonflies are stout and strong-flying, and they rest with their wings held open. Damselflies are slender, weaker fliers, and they fold their wings along the body when settled. Dragonflies also have eyes that meet in the middle of the head; damselflies' eyes are set apart like dumbbells.

Warm, still days are your window

Pick your moment. Dragonflies are sun-driven creatures and they are at their best in bright, calm conditions. An air temperature of roughly 18°C or more, with little or no breeze, will bring them out in numbers. The golden hours are late morning to mid-afternoon, roughly eleven until four, though southern hawkers and common darters will often still be on the wing into the early evening.

On overcast, cool or blustery days the pond can look empty. That is not a sign of failure. Wait for the weather, and they will return.

The season runs long. Large red damselflies are usually the first, appearing from late April. Numbers build through June and peak in July and August, and common darters can be flying into October, sometimes later in a mild autumn. A warm, settled spell after a spell of rain is often the best of all.

Where to stand and what to look at

Position matters as much as timing. Think of the pond as a series of zones, each used differently.

• Sunny edges: a south-facing bank warms first and holds most activity early in the day. Stand with the sun behind you so your own shadow does not fall across the water.
• Emergent plants: iris, soft rush, sedge and water mint are used as perches, look-out posts and egg-laying sites. Watch the tips of leaves and stems.
• Floating leaves: lily pads and floating heart make excellent basking platforms, especially for chasers and darters.
• Open water: the middle of the pond is the territory of patrolling hawkers and emperors, flying a regular beat.
• Shelter nearby: a hedge, fence line or tall border gives them somewhere to hunt and to roost out of the wind.

Move slowly and stand a couple of metres back. Dragonflies have excellent vision and will keep their distance if you loom over the edge. Settle somewhere comfortable and let them come to you.

Reading the behaviour

Half the pleasure is working out what they are doing. A male flying steadily up and down the same stretch of water is patrolling, defending a territory and hoping to intercept a female. Sudden erratic dashes and tight turns over the pond or into a hedge are hawking — feeding flight, catching midges, flies and small moths on the wing.

Some species, particularly darters and chasers, perch, returning again and again to the same stem or stone. If you find a favoured perch, you can watch it for an hour. A pair flying joined together, the male gripping the female behind the head, are in tandem, and may settle into the wheel position to mate.

Then comes egg-laying. Some damselflies and hawkers insert eggs into plant tissue, working their way down a stem; darters flick the abdomen down to tap the water surface, releasing eggs that sink to the bottom. It is worth watching quietly, because this is the moment your pond stops being a visitor attraction and becomes a nursery.

Making the pond better for them

• Plant up the margins with native species such as yellow iris, water mint, soft rush and greater spearwort.
• Keep a good proportion of open water clear of vegetation, so patrolling species have room.
• Leave stems and seed heads standing over winter — nymphs climb them to emerge.
• Think hard about fish. Even a few will eat nymphs and tadpoles. If you already have fish, provide dense cover and accept fewer dragonflies.
• Aim for at least six hours of direct sun on the water each day; shade from overhanging trees is the most common reason a pond stays quiet.
• Avoid chemicals, fertiliser runoff and blanketweed treatments. Clean, nutrient-poor water is what you want.

A few species to know, and how to record them

Start with the regulars. The common darter is small, with a red-orange male, and perches on bare ground and warm stones well into autumn. The southern hawker is large, green and blue, and famously inquisitive — it will hover and stare at you. The emperor is our biggest, a powerful blue and green insect that patrols mid-water. The broad-bodied chaser has a broad, flattened blue abdomen and perches very prominently on plant tips. Among the damselflies, look for the azure, blue-tailed and large red, all of which favour the margins.

Keep a simple note of what you see: date, weather, species, and behaviour. Records like these are genuinely useful, and your county record centre will welcome them. Over a few summers you will build a picture of your own pond that no book can give you — and you will notice the exact warm, still day when the season suddenly begins.