Clouded Yellow

• Latin name: Colias croceus
• Family group: Whites and yellows
• Countries: England, Scotland, Wales, Ireland
• Size: Medium

Regular migrant

The Clouded Yellow is one of the truly migratory European butterflies and a regular visitor to Britain and Ireland. Although some of these golden-yellow butterflies are seen every year, the species is famous for occasional mass immigrations and subsequent breeding, which are fondly and long remembered as ''Clouded Yellow Years''. A small proportion of females are pale yellow (form helice), which can be confused with the rarer Pale and Berger''s Clouded Yellows.

Conservation status

• UK BAP status: not assessed
• European threat status: not listed

European/world range

North Africa and southern Europe and eastwards through Turkey into the Middle East. It occurs throughout much of Europe as a summer migrant, but very few individuals reach Scandinavia.

Foodplants

A range of leguminous plants is used, including wild and cultivated clovers (Trifolium spp.), Lucerne (Medicago sativa), and less frequently, Common Bird''s-foot-trefoil (Lotus corniculatus).

Habitat

Clouded Yellows may be seen in any habitat, but congregate in flowery places where the larval foodplants grow. As clovers are still commonly cultivated, the Clouded Yellow is one of the few butterfly species that has no difficulty locating breeding habitat in the modern farmed countryside. In southern England there is a preference for unimproved chalk downland.