I had a third floor @ Collingwood Apts. and we had a couple hundred of them living in a broken gutter/drain pipe about 40 ft from our balcony.
They would start streaking out in packs of 10 to 40 for an hour after sunset. It was a pretty crazy sight. There were many summer evenings spent drinking brews and watching the show. It was also great to see the reactions of the first time observers. I was surprised by how many people are totally freaked out by bats
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They would fly into the windows and wake us up occasionally but otherwise no incidents.