Best time to see: Aug to Oct

Key facts

A metallic green damselfly that has colonised Britain from the continent recently

First seen breeding in East Anglia in 2009, it has spread rapidly west and north since then

Habitat: ponds and slow-moving streams with overhanging trees, on which eggs are laid

Recognition

Metallic green like the emerald damselfly but longer (up to 48mm) and without the blue eyes and blue pruinescence

Spend much of their time basking on waterside trees, particularly willows and alders

Lifecycle

Females lay eggs into the bark of trees;these overwinter and hatch in spring, falling into the water below

Larvae start to emerge in July; adults are long-lived, sometimes lasting into November