Hi Mark,
I noticed the same yesterday evening. We could see some kind of smoke in the sky, we found that the smoke was big clouds of flying insects. Over Ville-Marie there was 15-20 nighthawk + maybe a hundred gulls. Over Lorrainville, around 10 nighthawk and probably close to a thousand of swallows, mainly barn and tree. It was a great air show! Waxwings were feeding too in good numbers.
During the afternoon, a big bat was feeding above my house and neighbors. It looked bigger than a robin. I have bad pictures to analyze.