In the early 1990's Speckled Wood were recorded around Nichol's Wood, near Witherslack, in the south of the county. There are historical records of its presence in the county, but it disappeared in the early 20th century as the species underwent a contraction in range back to Wales and the South West. Although an expansion in range took place later, it is generally thought that its reappearance in Cumbria was an unauthorised release, as other colonies were too far away.

For the next ten years the species spread out slowly in the immediate vicinity of Witherslack but in the first five years of the 21st century it has exploded in all directions across the county.

It first crossed the Leven Estuary into the Furness Peninsula, for example, as the new millennium dawned. But in just five years, by the end of 2005, it could be found all over this area in large numbers; indeed it now probably occupies almost every suitable patch of woodland habitat in the Furness Peninsula. In 2005 I counted 87 specimens in September along a track near the Irish Sea coast at Askham.

Speckled Wood can be recorded in all months from April to October. This is because, uniquely amongst our British butterflies, it can over-winter as both a caterpillar and a chrysalis. Those over-wintering as a chrysalis emerge in April and peak in May while those over-wintering as a caterpillar produce a peak of adults in June. Both then go on to have over-lapping second broods which tend to peak in August/early September with a tail into October (in good years these may possibly be a third brood from those that originally over-wintered as a chrysalis). Thus, few tend to be seen in spring, more are normally seen in June but the largest numbers occur in late summer.

The Speckled Wood is a woodland butterfly preferring dappled shade - look for it where the tree canopy forms a tunnel with one end receiving good sunlight or where an adjacent hedge is enjoying good sunshine. Males like to perch on a shrubor branch in dappled sunlight. The eggs are laid on a range of coarse grasses.