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Clouded Yellow

Photograph by: 
Peter Orchard

An immigrant from northern Africa and southern Europe coming in variable numbers each year in late summer.


  • Clouded Yellow: the green-eyed monster

    Post date: Tuesday, 5 August, 2014 - 00:00

    Although we get an influx of immigrant clouded yellows (Colias crocea) in most years it always gives me bit of a thrill to see one. I suppose, when you first glimpse one, you know you have seen something slightly out of the ordinary. Some years they can be seen in good numbers; other years you barely see one! Occassionally we get an absolute invasion of them. They originate from northern Africa and southern Europe.

    Being on the south coast Dorset is the first landfall for some of the incoming insects and you can see clouded yellows here at almost any time from late summer right through until November if the weather remains warm. In some years they arrive earlier and those adults lay eggs which hatch out to give even greater numbers when the autumn arrivals hit land. Sadly, any eggs laid by the autumn team are doomed to die when the temperatures drop later in the winter. 

    Seeing one close up under the camera lens one can't help but be struck by its large green eyes and its brown toupee!


  • Clouded Yellow in Dorset: what your tweets tell us ...

    Post date: Wednesday, 10 April, 2019 - 21:13

    The clouded yellow is a relatively common migrant species arriving in Dorset in variable numbers each year and in some years there can be a major influx with clouded yellow being seen just about everywhere along the Dorset coast.. Most arrive in late summer and autumn but it is not unusual to see them much earlier in the year. They originate from north Africa and southern Europe and it is amazing that these relatively small insects can travel such great distances and even cross wide expanses of water to get here. They do lay eggs here and ones laid early in the year may well hatch and add to the immigrant population but the later ones rarely survive the English winter and so there is no real British population.

    The weekly reports show clouded yellow being seen in Dorset from as early as week 8 in February and small numbers are seen regularly from week 12 at the end of March right through until week 38 in mid September and then the number of reports climb and reach higher levels for about a six week period before tailing off. September and October are undoubtedly their peak season here.

    So far there are reports from almost fifty different sites in Dorset with the coast from Hengistbury Head, through the undercliffs at Boscombe and Bournemouth and then around the Purbeck coast to St Aldhelm's Head seeing the most. Certainly, the bulk of reports come from coastal, or near coastal, locations. You can encounter a clouded yellow almost anywhere along the Dorset coast on fine days in October. 

Common Name Clouded Yellow
Scientific Name Colias crocea
Species Group Pierid Butterflies Whites
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Similar Species

The records for this species have been organised into reports, charts, maps and photos. Click a pic below to see the detail:

Notebook Distribution Map Sites List Some Charts Some Photographs Recent Records Guidance Notes

To see related species click here: 

Pierid Butterflies Whites