Hanging With Bats

Whiling away under the Yolo Causeway and the adjacent causeway for the Capitol Corridor. Forest fire smoke from Northern California loomed above:

What is it like when the bats under the Yolo Causeway emerge at sunset? I wanted to find out.

I saw very few bats actually emerge, and the ones that did seemed to drop like stones from their cracks. They came in waves, and circled about under the bed of the freeway, their wings making a crackling sound. A wind tunnel of thousands of bats.