Clouded Yellow Colias croceus


The Clouded Yellow is an unpredictable annual migrant to Britain arriving from southern Europe in spring and dispersing northwards, occasionally occurring in huge numbers - about once every decade. It may be expected in many habitats where there is an abundance of nectar sources.


It has rich deep-yellow wings with solid black borders, which, on the female, are dotted with yellow spots. There is a pale female form helice. It almost always rests and feeds with its wings closed.

Flight times

The first arrivals are usually seen in May and June, with further immigrations possible between July and September. Numbers are supplemented by locally bred butterflies as it has a very rapid breeding cycle. It may be recorded until October.

Food plants

Food plants are clovers, Lucerne, and Common Bird's-foot-trefoil.

Distribution Maps

Clouded Yellow distribution map 2000-09
Clouded Yello distribution map 2010-14
Clouded Yellow distribution map 2015
2015 Summary
No of tetrads 23
First sighting 05/06/2015
Last sighting 21/10/2015
Clouded Yellow distribution map 2016
2016 Summary
No of tetrads 17
First sighting 03/06/2016
Last sighting 14-09/2016

Photo Gallery

Similar or Easily Confused Species and ID Hints

The rich golden yellow of the Clouded Yellow and bold black margins on the upper sides make it unlike any other British butterfly.

Brimstone Gonepteryx rhamni

The pale "Helice" form of the Clouded Yellow could be confused with a Brimstone. All forms of Clouded Yellow and Brimstone rest with their wings closed, hiding the bold black margins. The key differences being the shape of the rear edge of the wings and the shade of yellow, Brimstone having a slightly greenish tint, particularly the females.

Brimstone - © Simon Jenkins