Flies.

I was going to write a little urban pastoral bit about the interesting wildlife in my small city back yard. Or, I was going to write a complainy little piece about Daphne's current difficulties. Would've depended on my mood.
Instead, I am moved to write about my fucking disgusting fly infestation, and my absolutely gross late night incident involving thousand of dead flies and stinky water.
By 7 am, my covered back porch is a lazy, swirling fog of flies and there they stay until nightfall. Fly vortexes. They shimmer over the back yard and rest on the house walls. This has been going on for over a month. I have had city back yards, rural houses with chickens, and multiple dogs for years; never had this before.

What have I done? Raked all straw, dead leaves and shreds of debris in case they were breeding in decaying organic matter. (No sign of any subterranean insect activity except worms.) Pick up dog poop shortly after it hits the ground. No dog bones outside for now. Any food bowls get whisked inside immediately after use and cleaned. Crawled under the deck to check for fly breeding sources - nada. Trash covered, poop bucket sealed. Have hosed down the back deck with bleachy water and soap, several times. Have sprayed entire back area with vinegar (supposed to repel flies.) Checked adjacent yards for sources and activity. It all seems contained to my back yard, though.
Got a bunch of fly traps. The kind with awful smelling attractant you add water to. However, note the word "attractant". It attracts them, they drown in great numbers, but I have an unending supply of flies, so while satisfying to see them dead, it doesn't diminish the population. I've tried placing them in various places, but my back porch is still fly haven.
Which brings me to the revolting part. These traps are basically heavy plastic bags with a plastic thingie with holes on top. Flies crawl in, can't get out, die. Works great. I swear to doG they fill up with a good pound of dead & dying flies within a couple of days.
So last night I come home late and decide it will be less gross to dispose of the traps when it's dark and I can't see them. I reach up to take one down right outside the back door. (Luckily I'd left the dogs inside....) It slipped out of my hand and smashed on the deck, spraying a tsunami of dead flies and stinking attractant all over my legs, deck, and, did I mention all over my legs.
So at midnight I have a broom, the hose, a gallon of bleach and I am swearing and sweeping and hosing and anything to get rid of 5000 reeking, marinated dead flies. This morning, wash, rinse, repeat; taking care to get them out from between the boards which are a black sticky mass of fly corpses.
Finally the back deck is sparkly clean. But you know what? By 7 am, again, the fog of flies in back, thick as ever.
I want to be able to take my coffee out on my back deck, I want to sit out in the evening. But it's too gross.
Where are they coming from? Why my back yard? There's no uncovered trash. Nothing dead under the deck. I probably have the cleanest back yard in the city right now. I simply do not understand this. They are not cluster flies; they're outside and not clustering. These are common houseflies.
My next step will be, what? Chemicals?
But Daphne has inhalant allergies; and I really don't want to fog my back yard with pesticide for a number of reasons. I really don't. I don't know if it was the bleach (though I kept the dogs in and rinsed thoroughly) or what, but she came back in with her poor stupid little eyes all swollen up. I have rx eye goop, so she got that and TavistD and hopefully will be OK soon.
But I may have to try the big guns if I cannot figure out another solution. That, or just stay off my back porch until October. Yuck.