The small blue is the smallest of all the UK's butterflies. Adults are on the wing from May to August and can be seen feeding on common bird's-foot-trefoil or horseshoe vetch on chalk grassland, but only where kidney vetch also grows - the sole foodplant of the caterpillars. Males set up territories in sheltered places and the females lay their eggs on the kidney vetch; the emerging caterpillars feed on the flowerheads.
How to identify
Despite its name, the male small blue only has a small dusting of blue near to its body, otherwise it is a brown butterfly with pale, silver-grey underwings. The female is similar, but without the blue markings on the upperwings.
Did you know?
The small blue tends to live in small colonies of up to 30 individuals. Both sexes can be found in communal roosts, facing head down in the grass.
