This very cool thing is happening in our town right now. The Purple Martins are on a stop-over on their way to South America. They roost each evening in a line of Bradford Pear trees (no fruit) that line the edge of the parking lot by the Farmers' Market down in Shockoe Bottom. It's amazing. The sight of hundreds of birds flying low over our heads into the trees and the sound is amazing. I've never seen or heard anything like it before. A friend send me these photos as I couldn't capture any images the night we were there.