Shooting Times & Country Magazine
Rule britannicus
In early June this year, a friend took me to the Norfolk Broads to see swallowtail butterflies, which we did without too much trouble. I gathered that these spectacular butterflies are restricted in Britain to the Broads, and that they can only be seen for three or four weeks in June and early July. Thus I was surprised to see what looked like an identical butterfly flying, in some numbers, in Majorca in September. Was it really the same species?
Yes. However, the British race of the swallowtail, Papilio machaon britannicus, is slightly smaller than its continental cousin, Papilio machaon gorganus, and with more extensive dark markings. Intriguingly, the difference in behaviour is more 50 • SHOOTING TIMES & COUNTRY MAGAZINE the British swallowtail, is only found in the Norfolk Broads marked then the difference in the markings. Our swallowtails live in self-contained colonies, always in close proximity to the caterpillars’ food plant, milk-parsley, which flourishes in mixed fenland vegetation. In contrast, the continental swallowtails roam freely around the countryside and can be found in a variety of habitats. Their caterpillars feed on a range of umbellifers, including fennel and wild carrot. Our swallowtails usually have a single brood, but the gorganus insects have two and can be seen on the wing for several months of the year.
There is evidence that gorganus swallowtails were established on the downs in Kent and Dorset until the exceptionally cold summer of 1816, when they died out. The trend to warmer summers may well see this butterfly becoming established once again in southern England. DT