A friend e-mailed me information on an antique print entitled "Swallows flying south, swarming," from an old Frank Leslie's Illustrated magazine.

When I clicked on the link and saw the above print, I thought: Chimney Swifts. Knowing how many folks are big Chimney Swift fans around here, I thought I'd pass it along. 

(I think that Chimney Swifts may have been considered swallows back in the 1800s.)
 

The link to the print is here.