First of all, apologies for the lack of blogs in the last two weeks, we have had technical problems! However, all sorted now, so normal service is resumed!
Today’s focus is the clouded yellow, or Colias croceus to be scientific. Clouded yellows are beautiful butterflies and not a species we see very often here at Langford. The only recent records on site have been one in 2009 and an unprecedented 8 so far in 2013.
Their appearance really is stunning and unmistakeable, with bright canary yellow upperwings, edged with black and a small black spot in the yellow of the forewings. The undersides are almost a lime-green/yellow colour, with darker spotting and a white spot in the centre of the hindwing, ringed with brown.
Much like the more familiar painted lady, clouded yellows are immigrants to the UK, migrating northwards from north Africa and southern Europe. It is hot, dry weather that usually triggers this migration, as the butterflies foodplants dry up, forcing them to move north to enable feeding and breeding. The species occurs in widely varying numbers each year, depending on how many make it to the UK, some years with many thousands turning up and in other years, only a handful.
The butterfly does breed once it has reached our shores, with the larvae feeding on different species of clover, lucerne and bird’s-foot trefoil. Adults nectar on a wide variety of herbaceous plants and have been seen here at Langford feeding on knapweeds, clovers and vetches.
The best place to look for them is from the viewing screen on the public footpath as they have frequently been found on the grasslands surrounding Phase 1. And with 8 sightings already in the last couple of weeks, it certainly looks like a clouded yellow year, at least here at Langford.