What's going on in Portland, Maine - the bug has come to big cities.

I know this sub is pretty international but it is absolutely insane that this bug is infesting the city of Portland. Just out of nowhere this summer they've started swarming on houses in single-family neighborhoods in a city of 70,000 people. Friends of friends and family who live in the city have started posting photos of their houses covered in them on Facebook, as they started showing up last week. That's how they travel right? By the wind? It's insane to me that a forest bug is now everywhere in Maine and its bugs are suddenly in our cities. Sometimes I walk around my house and there are like 20 of them crawling on the siding...they're literally everywhere.