We’ve got an infestation of flies in our house–not your regular housefly, but these giant ponderous hairy beasts that are twice the size of a normal housefly. Given that it’s winter outside, where could they be coming from?
I’d sorta like to know, because if we’ve got some icky fly-breeding place in our house I’d like to eliminate it.
I had this problem last winter, and we were pretty sure that a rat had died in our basement’s crawl space. You’re not going to stop them from breeding until whatever they’re breeding in is gone, but you can keep them from spreading by placing lots of flypaper around your windows to catch the breeders. Because the infestation in our house was (mostly) confined to the basement, I took a can of RAID down with me, emptied it into the crawl space, closed the hatches, and then fogged the hell out of the basement. I did that three times in one week, and the infestation dwindled.
An exterminator will be able to do a better job of it, and not coat all of your household goods with deadly poison.
I had that problem a few years ago, we tried EVERYTHING. We cleaned the kitchen…nothing. Sealed the entire house…nothing. Went the opposite way, figured the fly concentration was higher on the inside, so we kept the windows open…no difference. Finally found it. The previous tennents had left two 6# bags of potatoes in the house. The potatoes had rotted away and what we where left with was two 5# bags of slimy maggots. There were literally (literally as in literally, not literally as in figurativley) hundreds of maggots in each bag. Get rid of maggots, get rid of the problem.
The first thing that came to my mind is cluster flies. They lay eggs inside walls and when the weather warms up, even transiently, the flies hatch out and enter the house. Then they swarm to any light source. I’ve never seen them myself, but they are supposed to fly more erratically than normal houseflies, often bumping into people.
I agree with the dead rat hypothesis. Maybe another animal, but most likely a rat. The same thing happens to me every few years. Be sure to seal up any small holes that might be enticing the little critters into your attic or basement.
A building I worked in was infested with these flies. It actually took years to get rid of them because maintenance didn’t consider them to be a problem. Strangely, you could leave food on your desk and they wouldn’t go anywhere near it. Don’t know what they actually ate.
Finally they sprayed enough poison into their hiding places and the problem finally disappeared.
Bob
3 years back, ours were caused by dead birds in the chimney.