Brown Argus

National Status

Occurs in England as far north as Yorkshire with range expanding northwards and eastwards. Population Trend: 10 years -11%; since 1976 -25%.

West Midlands Status

The West Midlands is towards the western margin of its range. Well distributed in Worcestershire and Staffordshire but less common and probably under-recorded in the other two counties. Evidence of range expansion. Population trend 10 years – increasing but with wide variation from year to year.

Habitat

Grassy slopes on chalk or limestone with Common Rock-rose Helianthemum nummularium. Increasingly, the butterfly has utilised various Geraniaceae spp. as foodplants and is now found in a wide range of new sites with early successional habitats including set-aside farmland, gravel workings, sewage wor

Flight Period

Can be double brooded and on the wing from early May to early October. The spring brood is poorly developed in the West Midlands.

Hotspots

Bredon Hill, Llynclys Common, Manifold Valley. Sites Trench Wood, Grafton Wood.

Caterpillar Food Plant

The main foodplant is Common Rock-rose (Helianthemum nummularium). Common Stork’s-bill (Erodium cicutarium) and Dove’s-foot Crane’s-bill (Geranium molle) are also used.