Chimney swifts are small birds that look somewhat like swallows. They fly in large flocks, chirping, eating insects on rising air currents. At night, they enter caves to sleep. Or in urban areas, they inhabit chimneys.

Here is a view of the chimney at Eglise St Jean Baptiste on Empress Street, on Ottawa’s west side. Chimneys do tend to be on the back of buildings, and this chimney is best viewed from the street behind, Upper Lorne Place. Many hundred swifts circle the chimney for some time, then fly straight down into it. Inside, they cling with their feet to the brick joint lines, using their stubby tail to support them against the bricks.

The video was taken at dusk, around 9pm, earlier this week. Because it was nearly dark, and the pocket camera isn’t great, and the photographer is a dork, the image quality isn’t fab. But squint away, and be amazed:  http://youtu.be/YRpxiRhkdjg