The Adonis Blue butterfly is the brightest of all the Uk's blue butterflies. The shade of blue can vary from area to area. The other distinguishing feature is the fine black lines that extend beyond the blue, to the edges of the wings. It is only found in southern England and Rodborough Common is well north of its normal population. It flies in May-June, but can have a second brood in August-September. It feeds on yellow horseshoe vetch as shown in the middle photo.