Flies!

[Gt86]

We had another viewing on the house we're waiting to exchange on, and found that in one bedroom, the curtains are crawling with flies.

Any idea what would cause this?

The house has been vacant for about 7 months

Nearby farm
Bins
Dead animal in the loft

Cluster flies probably

Something is dead! Rat or mouse most likely! There might be a gap in the flooring or piping somewhere.

We went on holiday and returned to our flat covered in dead flies just like that. They'd clearly been flying around because there were fly poo marks on the light fittings and windows. We found a desiccated mouse under the sink 😱

I would vote a nearby dead thing!
In a former house we had mice in the basement. Once pest control came in and mice started dying, the flies arrived. Grim. 😬

Almost certainly cluster flies. Look them up on Google and see if they fit the description.

They are a nightmare to get rid of, because of their life cycle behaviour.

I ended up having to call in a professional to smoke bomb the loft after inheriting them in a house I purchased.

Another vote for cluster flies, they come into small spaces to hibernate for the winter (I think) but they get disturbed and and fly sleepily around. They are easy to kill because they don’t really fly away but there are often loads of them and they seem to come back year after year. We get them in the window seals of a couple of our windows.

Should add that if they are Cluster Flies your Vendor will almost certainly know about them.

If you haven’t exchanged yet, ask the question. If it was me I would ask them to pay the bill for their removal.

The house is in a market town, so not really rural, and the flies seem to be contained to one bedroom.

Would that be typical behaviour for cluster flies, or would there be evidence throughout the house?

Not unusual to just be in one room.

edit to add - there is a window in my in laws house they like to try and hibernate in (it is south facing) so they are often to be found in there but nowhere else

Given their size and number - cluster flies. Pull the curtains back and inspect the open windows fully. We had exactly this problem in a 10yo flat; hundreds of them nesting in the window frames, which meant we couldn't open them (it did back onto a field). The maintenance chap came and did something with some sealant or mastic or something which made them go away, but I was also told they return to the same location year after year, so it might be a problem a bit further down the line (it was a 2nd floor flat, finding a permanent solution wasn't easy).

Their other favourite place to nest is lofts.

Cluster flies.
Thanks for reminding me of another reason I'm glad I moved!

(Although the cats used to like catching the "sky raisins" and apart from the noisy buzzing in the hedges in April (and a bit in September) they weren't a massive nuisance)

They do look very like cluster flies. The key is to find out how they’re getting in — through a light fitting in the kitchen extension in our case — and block the entrance up. Then kill the rest. Fly paper actually works.

Given that you’ve not bought the house yet though, I’d request that they paid for someone to smoke them out.

Yeah, also known as casement flies for their tendency to hang out inside window frames. I once opened a window wide and sat on the edge of the frame to lean out and get a good view of some fireworks nearby - with the room light off obviously. Came away from the room 10 minutes later to find my hair full of them. Aaaaaagggghhhh!!!

But in a single contained room like that...I mean, you kill them, they die, you squirt disinfectant into an areas where you find eggs, it's a very fixable problem, I would say, just a bit yuk cleaning up afterwards.

Bats in the loft can be another reason for cluster flies. We solved our problem, but putting in new down lights that sealed properly so the flues couldn't get down from the loft.

The above are likely to be right but a close up picture from above would be helpful. The other option is autumn flies... slightly different. I'd need a dorsal picture. Control is also slightly different.

We have had this twice, can happen over night.

No flies then suddenly 100 large flies, its pretty easy fixed with fly spray. They must all come from one batch of eggs (emerge at the same time and don't reoccur once you get rid of that batch).

Flies are real easy, Ants are hard work because they keep coming back and you have to seal your house up like a dolphines butt hole.