Insect and Spider Identification: Huge swarms of tiny flies every spring, 0 by AmandaLaud

AmandaLaud wrote:
Hi there,

We moved into a new home last April, and through most of the spring there were huge swarms of thousands of these tiny flies in my front yard. They would swoop around in unison - almost like a starling murmuration. Sometimes there are so many it looks like it is raining right in my front yard. They seemed to disappear deeper into the summer, but now that the warm weather is finally back, they have reappeared (worse than last year even). They cover our front window and our cars and have to be fanned away any time we want to walk outside the house. Oh, and when they land, the majority of them pair up by the abdomen (pictured).

Can anyone identify what these flies are, where they are coming from and is there anything I can do to reduce/get rid of them?

The house we moved into is very close to lake Ontario (less than 1km away), and less than 500m from a pond, so it can be quite damp/muggy. There was also fresh sod put down in the fall before we moved in.

Any insight would be greatly appreciated!