Grass is teeming with flys

[NC543212345]

I've just noticed our grass in the back garden is crawling with flies (is it flies of flys??)!
How do I get rid of them? The grass is kept short and there's no poo or anything on it so no idea why they have decided to congregate there.

It's this type of fly if that's any help

Could they be cluster flies?

Have they all just hatched? Maybe they'll all be gone by tomorrow.

No idea, they look fully grown though. They are all gathering together. Probably planning on how to invade the house next 🙄

Www.clusterfly.co.uk

I think they're preparing to invade earthworms

I think you might be right
Any idea how I get rid of them? All I can find online is how to get rid of them in your house, nothing about the grass.