Clouded Yellow Butterfly

©Margaret Holland

Clouded yellow

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Scientific name: Colias croceus
The clouded yellow is a migrant that arrives here from May onwards. Usually, only small numbers turn up, but some years see mass migrations. It prefers open habitats, particularly chalk grassland.

Top facts


Wingspan: 5.2-6.2cm

Conservation status

Migrant species.

When to see

May to November


The clouded yellow is a medium-sized, golden-yellow butterfly. It is a migrant species that flies here from North Africa and southern Europe. Clouded yellows are appear in small numbers most years, but occasionally turn up en masse - long remembered as 'Clouded yellow years'. Adults may arrive at any time during the spring and summer, and can be found in a variety of open habitats, although, in southern England, they are particularly fond of chalk grassland. Foodplants of the caterpillars include wild and cultivated clovers and common bird's-foot trefoil.

What to look for

The clouded yellow has bright yellowy-orange upperwing surfaces, lined with broad, dark edges, and a yellowy-green underside. It rests with its wings closed; two silver-white spots can be seen on the hindwings in this pose.

Where to find

Can turn up anywhere, but most frequent in southern England.

Did you know?

Clouded yellows are unable to survive winter in the UK, but they may become more common, or even residents, if temperatures rise as a result of climate change.