Ground Moths

Factual Questions
1

Walking through Montreal today, I saw close to 20 moths all fluttering furiously into the ground. They were flapping their wings but not flying at all, scraping their thoraxes into the dirt and occasionally bouncing a few inches in the air. And these were all individual moths spread out over a 2km path, so it seemed likely that this was the normal, independent behavior of these bugs.

Any idea what they were up to?

2

Could be laying eggs, if it’s a species whose larvae live on grass roots or some such.

Or it could be a mating thing - either a specific motion to attract a mate visually, or releasing pheromones.