While watching Eastern Red Bats and Big Brown Bats on Thursday, I ran into a bird watcher studying Chimney Swifts that roost at 944 Fifth Avenue at 75th.  It turns out the best place to watch them is the "hawk bench" where "regulars" watch Pale Male's nest in the spring.

The swifts swarm around the roost and then around 6:30 into the video they start to enter the roost.  In a few minutes, they are almost all inside.  Thank goodness for pre-war buildings.