Regional Species


Clouded Yellow
Colias croceus

Photograph by Janet Graham (Morfa Harlech)

Regional Species

In most summers this migrant butterfly is seen in very small numbers, if at all. Occasionally, however, there is such a large influx that it becomes a familiar sight in flowery places throughout North Wales. The last two such good years for the Clouded Yellow were 1996 and 2000.

An interesting feature of this species is that a small proportion of females are a much paler yellow - form helice. These have occasionally been mistaken for the very rare Pale Clouded Yellow or Berger's Clouded Yellow. The only other yellow butterfly is the Brimstone.