This species can be easily identified by the conspicuous yellow patch at the base of the hind wings, often extending up to the node. The fore wing is usually also yellow at the base, although less broadly so. The legs are black with yellow stripes.
Wing venation is black Male abdomen is slender, very straight-sided, not clubbed, deep orange rather than pure red, and have a complete black line running on each side of the abdomen.
Female abdomen is yellow, bluish-grey underneath and has typically a complete black line on each side. This line is usually partially interrupted in other species. Females vary quiet frequently, about 1 in 20 have reduced yellow on the wings.
The yellow wing bases may cause confusion with S. fonscolombii but S. flaveolum has darker wing venation and pterostigma. It does not overlap with yellow-winged Trithemis kirbyi.
This species is invasive in large parts of its range. It may be absent in a particular area for long periods, breeding there for a few years after the arrival of large swarms or migrants.
It can usually be found easily by going out in tufty, partly flooded pastures or grassland. Males will keep a small territory and under good years a lot of them their density will be relatively high. Males perch 20-50 cm up on vantage points in or between tufts, often returning tot he same after short dashes. They are very hardy and will keep their territory even on windier days. Those days they perch harder and one can come quite close to them.
Females are found in the same environment as the males but most of them are found a bit further away, in neighbouring vegetation. Flight is weak, bouncing or dancing in the air, reminiscent of a demoiselle.
Eggs are oviposited in vegetation that stands on dry land but will be flooded in early spring, when they hatch. Larval development is quick and can in hot summers be even quicker. Exuviae are left low and exposed in or very near water.
Sympetrum flaveolum occurs in the cold temperate zone of Eurasia and is common and abundant in most of its range. It is generally confined to mountains in the south of its range. The species is common and abundant in large parts of eastern and central Europe and the southern half of Fennoscandia. It has a permanent presence in most of the mountainous areas in western and parts of southern Europe, including the Pyrenees, the Massif Central, the Alps and the Dinaric Alps. Its occurrence in the lowlands of western and southern Europe is largely dependent on influxes from central and eastern Europe, which are associated with eastern winds. These invasions, such as those in 1995 and 2006, can be substantial and often result in the establishment of numerous temporary populations. In 1995, swarms of several tens of thousands of individuals reached Great Britain and there was a single record for Ireland. The resulting lowland populations are short-lived and in most cases become extinct after a few years. This pattern of influxes followed by decline and extinction is especially evident in Great Britain, with the species being absent or very rare in years between influxes.
In the core of its European range, S. flaveolum is found in a wide range of standing waters, which are neither too eutrophic nor heavily shaded. In the west and the south, it shows a strong preference for standing waters with shallow banks, which partially or completely dry out during summer. Suitable conditions occur at temporary flooded meadows, shallow dune lakes and small depressions in fen lands, bogs and quarries. The stable mountain populations of southern and western Europe are found at Sphagnum peat bogs, small alkaline or acidic lakes and temporary ponds.