The first Scottish Holly Blue record came from Dr John Walker, the ‘mad minister of Moffat’, seen in the Manse garden there in 1773. There have only been sporadic records from Dumfries and Galloway since, although the Holly Blue is well-established in Cumbria with colonies in Carlisle. In contrast, the southeast of Scotland (especially East Lothian and Edinburgh), has numerous colonies and it has been spreading slowly since around 2010.

However, the Holly Blue had an extraordinary year in Scotland in 2023, with records from Aberdeenshire, Stirling and Argyll. East Lothian recorded a 130% increase in the number of records, and in Dumfries and Galloway the four records submitted in 2022 were followed by 65 in 2023!

Identification

The Common Blue is sometimes mistaken for the Holly Blue but the latter has silvery blue underwings. Of the blue butterflies it is the one most likely to be seen in gardens or parks, as it is not dependent on flower-rich grasslands, unlike the Common Blue.

Life cycle & flight period

The Holly Blue has two generations a year, the adults flying from mid-April to late May, and again from early July until mid-September. Overwinters as a caterpillar.

Larval foodplant

In spring the females lay their eggs primarily on Holly, while in the summer they usually choose Ivy, the caterpillars feeding on the developing berries of both species. Other plants may be used however, and south of the border the spring brood has been reported as using Common Spindle and Common Dogwood, while the summer generation females can use Common Buckthorn, Snowberry and even Gorse.

Habitats

Most sightings come from urban areas and the Holly Blue is traditionally associated primarily with gardens, parks and churchyards. However, it can also be found in the countryside, for example along woodland edges rich in Holly and Ivy.