The Blue-tailed Damselfly (Ischnura elegans) is one of the most common damselflies in Norfolk, able to survive low water quality. It is also the smallest damselfly in Norfolk. Because of its small size it is affected by winds, and is frequently found on the downwind side of ponds.
The blue tail and small size are the best clues to identy, but the bi-coloured pterostygma is diagnostic. The blue tail is shared with the red-eyed, small red-eyed, emerald and scarce emerald damselflies, but the eye colour, size and prunescence should distinguish between these species.
Males emerge with a green thorax (see photo above) before maturing to the typical blue, while females occur in several colour variants. Newly emerged females are either pinky-red (rufescens) or a delicate lilac (violacea). Rufescens turns into a yellowish-brown form known as rufescens-obsoleta (previously called infuscans-obsoleta) while violacea matures into either a blue form identical to males (typica) or infuscans which has a brown thorax and tail.
This photo shows violacea on the cusp of turning to typicaError processing SSI file