The butterfly loosely resembles a small Meadow Brown, but the brown colour of the wings appears noticeably paler in flight. Unlike the Meadow Brown and other common members of Satyrinae, the Small Heath is a lateral basker, only ever resting with its wings closed and angled at 90° to the sun.
The larvae have lifespans of varying length, even within the same climate, thus the imagines of one generation may be seen over a long period. The butterfly usually has two, occasionally three, broods and is on the wing from mid May until early October (late June to mid August in colder climates). The insect overwinters in its larval stage.
The Small Heath, like its cousin the Wall Brown, has been in serious decline across much of southern England for reasons unclear, and was accordingly designated as a UK BAP Priority Species (research only) by DEFRA in 2007.