A female Brown Argus at Rodborough Common, Gloucestershire. © 2008 - 2019 Steven Cheshire..
The Brown Argus has chocolate brown wings with orange spots near the edge and fringed with white. There is a black spot in the centre of the upper wing. The undersides of the wings are grey/brown with white ringed black spots and orange markings.
The males and females are similar although the sexes can be distinguished by the orange spots. These spots clearly extend to the leading edge of the forewing in the females, while in the males, the spots are very pale or absent at this point.
Care should be taken as the Brown Argus and female Common Blue are very similar in appearance. The Brown Argus lacks the two extra spots on the underside of the forewing which are present on the Common Blue.
Flying low to the ground, the Brown Argus has a silvery appearance, frequently stopping to perch or feed on flowers.
Brown Argus butterflies will often roost communally in sheltered areas although this species is rarely seen in large numbers... usually only one or two individuals are encountered at a site at any one time.
In Warwickshire, the Brown Argus occurs in small numbers in a range of habitats including woodland clearings, heathland, disused railway lines, road verges, and set-aside fields.
The larvae of the Brown Argus feed on Dove's-foot Crane's-bill (Geranium molle). The larvae will also feed on Common Stork's-bill (Erodium cicutarium), Meadow Crane's-bill (Geranium pratense), and Hedgerow Crane's-bill (Geranium pyrenaicum).
See maps below. Distribution text required.