Cluster flies are pretty much harmless, as insects go (unless you happen to be an earthworm, but that is another story). They do, however, become a problem in the autumn – and periodically on warm sunny days throughout the winter and early spring – as they enter buildings to hibernate. They get their name from their habit of clustering in vast numbers at such times. They will often return to the same building year after year. In my case, their preferred winter venue is the ticket office. They love it. It has everything a cluster fly needs for that perfect hibernation destination.
This means that every time I enter our ticket office it’s like a scene from the Amityville Horror. The fly clustering scene, most particularly. The windows are black with lazily buzzing flies, the sills and floor covered in drifts of the fallen. These fallen flies should not be confused with dead flies. They are the fallen undead, with randomly reanimated individuals suddenly flying back up toward the light in dozy circles.
Tackling these beasties is problematic. Chemicals are not only ineffective but could well have a detrimental effect on the other friendly creatures that live in the building. Bug zappers can only handle so many bugs at a time. That leaves our method of sucking them up the hoover. This needs to be done daily, as the clusters of flies return, biblical plague-like, within hours. Emptying the hoover afterwards can be a traumatic experience if you haven’t thought it through.
I recall a day last year when I proudly took the ticket office staff a gift of a cordless handheld vacuum cleaner, for fly busting activities. I spent a happy few minutes hoovering up all the cluster flies that had magically reappeared since the last big blitz. The “handy-vac” was by now full and lightly thrumming with the vibrations of innumerable flies. I took it outside to empty it. This was a Stupid Thing to Do. As I took the unit apart hundreds of undead, somewhat dusty, flies swirled upwards to get in my face and hair. The resulting squealing like the great big girl I am and leaping around, frantically brushing out my hair, was witnessed by every visitor walking by on the path at that time.
This year I am going to continue my quest for a better solution to my cluster fly problem. Experiments with super large spiders continue.