Brown argus

Brown Argus

Brown Argus ©Amy Lewis

Brown argus

Scientific name: Aricia agestis
The Brown argus favours open, chalk and limestone grasslands, but can also be spotted on coastal dunes, in woodland clearings and along disused railways.

Species information


Wingspan: 2.5-3.1cm

Conservation status


When to see

May to September


The Brown argus is a small butterfly that is on the wing throughout the summer, between May and September. Adults feed on Common Rock-rose, which is also the caterpillars' foodplant, together with various species like Crane's-bills. The Brown argus is found in dry, sunny and open habitats, including heathland and downland, and seems to be expanding its range as the climate warms up.

How to identify

The Brown argus has bronzy-brown upperwings with an orange band of spots across the edge of each wing. It is very similar to the female Common Blue, but tends to be smaller, with no hint of blue in the wings.


Found across southern and central England and parts of the Welsh coast.

Did you know?

A very close relative, the Northern Brown argus, is found in northern England and Scotland and is a Priority species under the UK Post-2010 Biodiversity Framework. The Northern Brown Argus does not usually have very prominent orange spots on the forewing.

How people can help

The Wildlife Trusts manage many grassland habitats sympathetically for the benefit of all kinds of butterflies, including the Brown argus. Careful grazing with traditional breeds, hay-cutting at the right time and scrub clearance are just some of the ways grasslands are kept in good condition - supporting invertebrates and, in turn, the larger animals that prey on them. By volunteering for your local Trust you can help too, and you'll make new friends and learn new skills along the way.