Several folks have posted stills in the past so it's interesting to see your video.

If I recall correctly, they're fly larvae of a certain kind of fungus gnat. Only a curiosity; not a problem.

Perhaps rhizo will be along soon to confirm.

You recall correctly, Jean. This is a migrating 'herd' of fungus gnat larvae. Many species of fungus gnats behave this way; isn't it interesting?

In general terms, Tim, where are you located?

I meant to ask, Tim...have you put down any mushroom mulch or similar product lately?

You Easterners have some [redacted] critters.

Dan

I live in VA. This is a new house. There is some decaying straw that was put down a year ago or less. No mulch in that area.

Oh, well...just trying to learn more about why they mass migrate. It's a phenomenon that is not clearly understood and is rarely witnessed. There is clearly a damp, humus-y area somewhere nearby so that such a population of these insects could build up to this level. Might not even be in your yard.

I'll say one thing for sure: they are going to pupate soon, and there will be one big hoard of tiny little fungus gnat adults swarming all over the place! Fungus gnat life cycle is a very short one.

Thanks for the video. As Jean mentioned, we see pictures of this from time to time, and get the craziest descriptions, but I've not yet seen a home video!