Best time to see: late Jul to mid Oct

Key facts

A medium-sized dragonfly of late summer and autumn

Habitat: ponds, lakes, gravel pits and slow-moving rivers; can tolerate brackish water

Common in south-east England, with regular migrations from Europe in late summer

Recognition

Males mainly blue, females brown and dull yellowy-green; yellow triangle at base of abdomen is distinctive

Often seen flying at treetop level in woodland glades or along hedges; males patrol low down along the waterside

Fly from July well into October, preying on flying insects

Lifecycle

Females lay eggs in plants such as bulrush or yellow flag, often above the water line and usually alone

Eggs survive over winter, larvae hatching in spring and developing rapidly

Larvae crawl up a plant stem in late summer or early autumn and emerge as adults