The Brimstone is an early arrival in the gardens, being one of the few UK butterfly species to hibernate as an adult. After a winter sleeping in holly, ivy or bramble bushes, it emerges during the first warm spring days. We also see the Brimstone a good deal in early autumn, when it is busy seeking out nectar to build up its energy reserves for the coming months.

 

It's a comparatively large butterfly and when roosting the angular shape of its wings closely resemble leaves. 

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The bottle-shaped eggs are laid singly on the underside of young buckthorn leaves growing in the surrounding hedgerows. The bluish-green caterpillars emerge towards the end of May and can quickly decimate the buckthorn foliage. The chrysalis is green with purple markings and shaped like a curled-up leaf, so can be hard to find.