Blow fly?

[pwnell]

Is this a blow fly (Calliphora vomitoria)? It is winter here and for some reason I have a hundred of these flies in my house. Sometimes they cluster on windows, they fly sluggishly and keep on arriving even though I have captured and killed at least 60 of them. If I can identify what they are, perhaps I can understand where they come from. I do not have garbage older than 7 days in my house.

[Chris S.]

Unfortunately, my guess would be a dead mouse somewhere out of sight. (Don't ask why this comes to mind!)

--Chris S.

[razashaikh]

Nice Work.

[pwnell]

[Olympusman]

Yep - I agree. Dead`critter in the house. The female fly laid only so many eggs. After those maggots have matured and you have spent a couple of days swatting, you will see no more flies. Had a similar experience last spring.
To save time on the swatting, go to an auto parts store and get some cold weather quick start spray which is very effective on flies and wasps, and if you don't ventilate effectively, you will get a nice buzz.

Mike
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Michael Reese Much FRMS EMS Bethlehem, Pennsylvania, USA

[pwnell]

[MarkSturtevant]

Looks like that species. I agree it is from 'something' that they can grow on.
I had the same experience here in Michigan toward the onset of winter once. They kept turning up in numbers, and then one day about 200 appeared. Must have been a synchronized emergence from wherever.
All I can say it that it passes.
_________________
Mark Sturtevant
Dept. of Still Waters

[ChrisR]

I gave up trying to catch flies, thinking that they'd be an easy subject, to do a careful anatomical investigation. I couldn't encourage any, even with festering pet food or droppings.
A case of being careful what one wishes for...
_________________
Chris R

[pwnell]

Well, they have all gone now so at least there is that. Not sure where they came from - could not find anything in the house. But then there is a lot of attic space and there is the central heating ventilation ducts too. Guess this will remain a mystery.

[Deanimator]

I had a similar problem with tiny gnats earlier last year.

I thought I'd taken all organic garbage out, but I couldn't get rid of them.

Turns out I had a plastic sack of potatoes in a rolling bin that I'd forgotten about when my A1C started going up.

It was a nasty mess and within a couple of days of throwing it out and washing the bin, they were all gone.

Of course now I have no living things of which I can take macro photographs...

[pwnell]