Like the Painted Lady, the Clouded Yellow is an immigrant from Southern Europe and North Africa, but it is one which arrives in a much more irregular pattern. 2006 seems to have been a particularly good year but the last time before that when it was seen in good numbers in Cumbria was 2000, with only a handful of isolated records in the years between.

This species is always warmly welcomed by butterfly enthusiasts as there is no comparable sight in this country to that of this bright yellow and black butterfly fluttering about amongst our native plants .............and it could be ten years or more before he or she sees it again!

Despite travelling thousands of miles they often arrive in a very fresh state - wear only starts when they begin moving around in the undergrowth. The current consensus is that immigrant females normally arrive already mated and ready to lay their eggs, which generally happens in late May or early June.

This species has difficulty breeding in this country as it seems that cool wet weather kills the larvae and chrysalises. However a spell of dry hot weather will aid successful breeding and help numbers to build up - and July 2006 kindly obliged with a mini-heatwave! In those rare years when this happens sightings therefore occur around mid August and early September as the adults emerge.

Foodplants of the larvae include clover and bird's-foot trefoil. The species liking for the former means that it is the only one of our butterflies that readily breeds on improved grassland (sown with clover).

Sightings are most frequent around the coast of the county, especially the northern shores of Morecambe Bay and up the west coast. Bardsea, Aldingham and South Walney held good numbers in August 2006.

Visitors to the churchyard and shore at Aldingham, for example, were able to see good numbers nectaring on the valerian on the retaining wall throughout August and early September, suggesting that they have indeed bred nearby. There were up to 10 on many sunny days in August and early September 2006, together with up to 35 Small Tortoiseshell, numerous Painted Lady and innumerable Silver Y moths (an immigrant moth that often arrives on the same weather systems as Painted Lady and Clouded Yellow).

Rather annoyingly, this species never settles with its wings open, so the beautiful sulphur yellow and black markings of the upperside of the wings are not easily seen. They are best glimpsed as the butterfly takes off for flight or just occasionally when at rest when they briefly flex their flight muscles. However, when seen at rest against the light the intense yellow colour will often show through to the underside.

Females generally appear brighter, slightly larger and more strongly marked. The uppersides of the wings have a wide black borders but in the female they are broken by ragged yellow spots and these often show through to the underside (see photo above left). Males are a touch smaller and the black spotting on the underside of the wings may be less pronounced (photo right).

Close inspection reveals that this species has a wonderful green eye and a long proboscis (see below)!