This is one of the most common dragonflies in Ireland. Adults are on the wing from June to late October or early November but are particularly conspicuous in August. The mature males are orange with yellow-striped legs. They are a common sight basking in the sun on bare ground beside water.
The larvae live in still, lowland freshwater, especially ponds and small lakes. They are rapid coonises of newly created ponds including garden ponds, and can also occur in slightly brackish water. The Common Darter is absent from upland sites (above 200m), rivers and streams.
The lifecycle of this dragonfly is completed in a year. The adults emerge in early summer, spending several weeks in woodland as they mature. They reappear beside the lakes in late summer, mate and the females lay the eggs. These hatch in early spring and the larvae then grow rapidly to full size in early summer.
The species is interesting taxonomically, as western forms in Europe, have been treated as separate species, including one Sympetrum nigrescens Lucas which is considered to be present in western Ireland, Scotland and south-western Norway. The evidence for this is not strong, but more research is needed.