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Zombies at my window: What’s with those cluster flies?

JAY DART/The Globe and Mail

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The windows of my old house are covered with cluster flies, dopey creatures that spend their time trying to get inside in the fall and trying to get out again in the spring. They are feckless creatures who seem to exist only to annoy.

The cluster fly is not like the mosquito, which is canny and has personality. It is stupid and sluggish and has no interesting abilities.

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It doesn't suck blood or transmit deadly diseases, but instead preys upon a more modest life form: the hapless earthworm. The cluster fly lays its eggs in the soil in a newly plowed field so that, when a curious earthworm wriggles to the surface to look around, these fly offspring can attach themselves to the innocent worm and proceed to eat him up. So worms expire and I get more flies in the house. What is the point of all that?

Once inside, these flies have nothing better to do than wander around on windows and then fall to the floor as if dead.

After a few hours of lying motionless, they get the bright idea to fly up to the window again for another look. Then back to the floor they fall again, where they may spin around on their backs for a while and then play dead for a day or two.

That's the really perplexing thing about cluster flies. At any point in their life, they can appear to be dead, half dead, almost dead or nearly dead, but, like zombies, they never quite expire. How many times have I bent down to pick one off the carpet only to discover that the corpse has a few good buzzes left in him?

I once thought the cluster fly was just a run-down house fly, but real houseflies, which are a bit smaller, are frisky and task-oriented, determined to sit on your dinner – or whatever – any time they get the chance.

Cluster flies don't give a hoot about dinner. They prefer the light bulb on the ceiling, where they walk about aimlessly while considering their next moment of death. As we dine below, giant fly shadows travel around the room, giving us the impression that cars are going by. Shadows are tolerable, but we know what comes next. The butter usually breaks their fall.

Cluster flies are filled with glue. I have tried all manner of cleaning potions on the window sills to no avail, though I have removed a considerable amount of paint. Did I mention that when cluster flies really do die, they explode and leave a fine grey spray of guts in unreachable places? The only way to get rid of fly specks is to scrape them off with a fingernail, which makes for a good day of farm fun.

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Those bug zapper tennis racquets are dandy for mosquitoes, though you have to be a pro to fry a genuine house fly. The cluster fly will land on the electric grid of its own volition. A few gleeful zaps cause it to bounce and roll about a bit, but of course it doesn't die. Instead, the shock treatment seems to revive the darned thing so it can careen off to drop inside someone's collar. Funny!

The last person in the house to turn out the light is bound to be bunking with a couple of cluster flies. They love to spin around inside that halogen hell that is the reading lamp, and, being cluster flies, they don't burn to a crisp, they just bash about until near death, then drop out to cool off in your hair. Or, they stay very quiet until you turn out the light and then they plop onto the pillow.

The sensible thing to do is to leave the bathroom light on all night so all the flies in the house can happily congregate there, and at sun-up they can buzz on over to the window for the day.

This is the time to exact my revenge, which comes in the form of glue paper. One sheet stuck to the window will catch dozens of insects in short order. They land, they stick, they buzz a bit, and then they just sit quietly … not quite dead, of course.

A small breeze will bring them all to life at once, so whenever you walk by the window, a chorus of cluster flies will rise up, calling to be set free.

When the glue paper is well populated, it's disposal time. This is not for the squeamish, because as soon as those nearly dead creatures feel the motion of being carried to the bin, they all try to lift off at once, which makes the trap vibrate uncomfortably, and the hair on my arms stand on end too.

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I once tried to vacuum the not-quite-expired bodies off one of those pricey glue papers, but all I got was a bunch of flies minus their feet. Too cruel, I decided.

One spring day, as I was removing yet another fly-laden glue paper from the bathroom window, I was surprised to see a tiny flycatcher out on the ledge, the one who has her mud nest stuck up under the eaves.

She is the most successful of our yard birds, raising two batches of babies per season and returning year after year to the same nest.

And she was happily pecking cluster flies off the outside screen. She eats cluster flies! Mother Nature is not crazy after all.

Marcia Taylor lives in Ottawa.

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