The hind wing underside is often ocher to reddish brown and stands out from other species of the genus.
[2] It is sometimes considered a subspecies of the Carline Skipper (P. carlinae) as the two are known to interbreed where their ranges overlap in the Alps but can usually be recognised by the prominent squarish, rather than c-shaped, white spot near the costa of the forewing and the usually deeper red-brown underwings.
[3] A reliable separation in this genus, which is difficult to determine according to external characteristics, is possible through genital examination.
[2] According to current knowledge, there is also evidence from the Caucasus and Eastern Anatolia, as there are several isolated populations in north-eastern Turkey and in Armenia.
[4] The current habitats of Pyrgus cirsii are sparsely overgrown, with open ground interspersed, full sun dry grasslands in stony, shallow and base-rich locations.
Almost without exception, the current habitats are subject to regular and relatively intensive grazing, and they are also characterized by large pads of Potentilla verna agg.
A minimum size of the living space with corresponding open ground structures or the very close connection of these dry turf areas is obviously essential.
[2] According to current knowledge, Pyrgus cirsii caterpillars probably lives exclusively on cinquefoil species (Potentilla, Rosaceae).
The caterpillars live in the leaf bags characteristic of the Pyrgus species and can therefore be searched for in a targeted manner.
[2] Both sexes of Pyrgus cirsii are based on the structure of the terrain and specifically seek out the areas with little vegetation.
Increasing isolation might be a main reason for the strongly regressive population development of the species.