Clouded yellow

Clouded Yellow Butterfly

©Margaret Holland

Clouded yellow

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.

Species information


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.

How to identify

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.


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.

How people can help

The Wildlife Trusts manage many grassland habitats sympathetically for the benefit of all kinds of butterflies, including the Clouded yellow. 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.