Clouded Yellow
Colias croceus
Tap image to enlarge · Wikimedia Commons
Overview
The Clouded Yellow is one of the most exciting butterflies to see on the Sefton Coast — a vivid lemon-yellow migrant that powers along fast and low over dune grassland. In good years (known as 'Clouded Yellow years') large numbers reach the Sefton Coast, the deep golden-yellow males and paler females feeding on Clover and Bird's-foot Trefoil. The frustrating thing is that it rarely opens its wings at rest, making photography a challenge. When it does open its wings briefly in sunshine, the vivid yellow-orange is extraordinary.
At a Glance
| Order | Lepidoptera |
| Family | Pieridae |
| Habitat | Open dune grassland · Coastal clover fields · Any open area with Clover or Trefoil |
| Diet | Adults: flowers — particularly Clover and Bird's-foot Trefoil. Larvae: Clover, Lucerne. |
| UK population | Entirely migratory; abundant in good years, scarce otherwise |
| Sefton Coast | Irregular — occasional singles most years, large numbers in good migration years |
| Conservation | UK Green List |
Where to See It
Open dune grassland and coastal clover fields. Difficult to see at rest — rarely opens wings.
Identification
Deep golden-yellow (male) or pale yellow-white (female). Dark border on upper surface rarely seen — usually rests with wings closed. Underside: yellow with orange spots and a bright orange circle on hindwing. Fast, powerful flight.
Viewing & Photography Tips
Walk open dune grassland in August–September in warm weather. Look for fast-flying yellow butterflies — much more powerful flight than Brimstone or whites. They settle regularly to feed on Clover.
Conservation Status
UK Green List
This species has a favourable conservation status in the UK and remains an important part of Sefton Coast biodiversity.
Frequently Asked Questions
What are 'Clouded Yellow years'?
Some years see enormous influxes of Clouded Yellows from southern Europe, when favourable winds carry large numbers across the Channel and into Britain. These 'Clouded Yellow years' (notably 1983, 1992, 2000) are memorable events for butterfly watchers. In good years, thousands may reach the Sefton Coast. The species cannot survive the UK winter — all individuals must either migrate south or perish.
Related Species
Plan your visit to the Sefton Coast
Marshside RSPB, Formby pinewoods, Ainsdale NNR — practical guides to getting there, what to bring, and the best spots for each season.