St Mark's Flies

St Mark's Flies

Near the end of April and the beginning of May, on those warm sunny days that punctuate spring showers, the country air is filled with large glossy black flies. These ferocious looking creatures drift in the air above the hedgerows, trailing their legs in a most menacing manner but zooming off suddenly if approached. In fact they are completely harmless and simply looking for a mate.

AKA Hawthorn Flies

They are known variously as St Mark’s Flies – because they emerge around St Marks Day (April 25th) – or as Hawthorn Flies because of their predilection to group over hawthorn bushes in hedgerows.

This year (2012) they must have had a hard time of it, for despite fine weather around Easter, the last several weeks have seen rain of almost biblical proportions and they have had few sunny days to fly and breed. Like mayflies, their adult lives are short, they will survive only a couple of weeks and will die soon after mating, however their eggs will hatch into grubs which live in the soil for years, until they emerge again in early May for a few brief days in the sun.

All material © Philip Stone 2012