Over 50 blue bottle flies in the bedroom!!!

[VanityKase]

We went away this weekend (Friday & Saturday night); came home today (Sunday) to find over 50 dead / dying blue bottles on & around the bedroom window sill! 🤢

Some made their way to the bathroom & one or two were on the stairs.

There isn’t any OBVIOUS source (bibs, recycling & food waste taken out on Friday’s bin day, & kitchen door was closed & fly-free). Haven’t seen any flies downstairs at all.

Have we got a hidden rotting carcass somewhere waiting to be horrifically discovered?! 😫 We do have 1930’s wooden floors under our carpet & a shoddily-blocked-up fire place in the bedroom.

What do we do from here??
Advice welcome!

Could be you've had a dead mouse or something in the loft or chimney or elsewhere. Had you had any smells before you went away? It only takes one fly to get to the carcass and lay eggs and a week or so later you're inundated with flies who will come out of any cracks or gaps (I'm telling you this from lived experience ☹️)

It might be a type of nest in the outside bit of the window - are they wooden window frames|?

Do you have a cat? Years ago we had similar and found a dead mouse under our bed...

Yes, look for nests
any obvious smells? Could something have crawled into the pipes?

We had this with a dead bird in the boarded up fireplace in our 1930s house. It was like a horror film. We couldn’t rip off the wallpaper to get to it, because we were renting. But it only lasted three days, presumably until the maggots had all hatched and squeezed out.

Yes, there is probably a carcass somewhere. It's unlikely you will be able to find it- it could be in the wall cavities or under the floorboards- anywhere. Good news is it should only last a few days (until all the maggots have hatched...😬)

…or are they actually cluster flies?
They’re not very metallic.

I remember a similar situation in my son’s Victorian house. An unbelievable amount of dead and dying bluebottles on the bedroom windowsill. Sweeping them up with a brush and dustpan 30 or 40 at a time. Then by morning there would be lots more. Pest control officer quickly identified the source was a dead bird in the old unused chimney. He said by the end of the week the hatching cycle would be over and the problem would end and that’s precisely what happened.

Look like cluster flies to me. I had them. Bloody nightmare. Had bin liners full of them after the pest man came out. They were in the loft. The electrician opened the loft hatch before I could warn him before the pest man came back to collect them in the bags and they fell on him. He screamed. They also were in the water tank and I had to put a pair of tights over the taps in the bath to filter them out. Got it sorted eventually but then I moved out.

We had this with cluster flies about 2 weeks ago, on windows in 3 rooms. Couldn't find a reason at all. It stopped after about 4 or 5 days. Everything I read online said to keep windows closed but the flies that were alive were trying to get out so we actually found it reduced numbers to have the windows open during the day. Hopefully yours will pass as quickly if you can't find the cause.

Thanks all!

I do think they look more like house flies or cluster flies but I didn’t see all of them on the window sill close up before DH hoovered them up. Heard the one above doing their last buzzes from inside a plant pot so it’s the only one I could photograph.

No odd smells (so far…); no unexplained scratching noises at night from in the fire place; no wooden window sills just PVC ones. We do have a cat but she’s indoor only so wouldn’t have been bringing us in a present & we’ve had no mouse issues in this house (have had them in previous place so would recognise some tell tail signs if we had some).

Glad to hear the phase doesn’t last long and hopefully most of the hatching happened when we were away.

@m00rfarm oh my days!!!! That sounds horrendous! Do you live on a farm as your user name suggests? I’ve read they are more of a rural issue is all and I’m not particularly rural here so hoping it’s not as extreme as your experience! That is surely the worst experience that electrician has had though 😂

@Veenah what kind of numbers did you have over the course of the days? Did they start off low in number and build up or suddenly all appear at once? Just trying to prepare myself 🙈

@VanityKase we had them and no matter what I tried every morning they reappeared. In the end we got rid of them with those sticky strips. Hung them by the window and eventually they disappeared. I think they have a poisonous odour or when touched so be careful handling them.

Are they a bit sleepier than normal flies? That’s what I had when there was a dead bird in the chimney. Horrendous- good luck OP

They started off low, then peaked then tapered off. We weren't gone for a few days like you so it's hard to judge numbers as we were constantly clearing them. I'd clear the windows probably 4 times a day and each time every window had about 8ish if that helps you judge and compare. Sounds about similar to yours if we had left for a couple of days

There a fresh batch of them at the window this afternoon.

On closer inspection, they look a bit iridescent so blue bottles mean something decaying or rotting near by 🤦‍♀️🤢

I’m isolating each room to see if they’re coming from the bedroom or bathroom. I dear not look under the bed yet!

Any recommendations on good fly killing techniques? Cat friendly ones.

Is everything OK next door?
I'd worry that something had happened to the neighbour...

Oh dear. Good point.

They do look like cluster flies, we had a mini infestation last autumn. They were inside & outside around the window & when I used a fly spray absolutely loads came out of a gap in the brickwork so they were all in the cavity wall.
I consoled myself that they are harmless & don't have the filthy eating habits of bluebottles.
Not sure fly spray is safe with your cat but it put a stop to it.

I had this a couple of times- both times it was a dead bird in the chimney, which was blocked ish, but not enough for maggots to not get through. It was horrible, worse when at the larvae stage as I was literally finding maggots on the floor. If you're at the fly stage, it will pass soon, get the chimney swept and a lid thing put on them at the top.

Have you watched Amityville Horror? 😄

It'll be that your house is possessed like in Amityville!

OR

Do you have a chimney in that room? Could be a dead bird etc in the chimney

@WhisperingAutistic @EmmaEmerald next door are all fine! I was around their house this evening. I didn’t ask whether they were getting flies but I was looking out for them there - none!

@CocoPlum @FloofCloud We have a blocked up fire place in our bedroom, yes. Builders were supposed to add a cage thing at the top of the chimney when they repointed it but I’m starting to think perhaps they haven’t. I’m so glad I’ve not seen any maggots!! I’m hoping by the end of the week we’ll be fly free!

@FloofCloud @identifyingasmrblobbytoday ooooh! My first potential haunting!! 😂 I love to good horror movie so let’s see how this pans out! 😂

Def a dead bird in the chimney. We had this exact same thing. Def get a cowl on the chimney asap. We had this two years running one year maggots and one flies. Ours was two dead jackdaws, nearly sent me insane trying to figure it out!

I had this in my garage. Just kept fly spraying, took about a week but they eventually all died. Mine were in a cycle about 20-30 a day. No obvious source, it was very odd