Every evening, with patience, you will glimpse chimney swifts dropping into and launching out of one of our chimneys. This year we have at least four in there. The stack they inhabit is not for a fireplace. It is used by the heater in our basement, but it's still hard to picture how they survive. Imagine a life spent entirely on vertical surfaces or in flight - amazing! Even bathing and drinking water are done on the wing.
This site has some great photos of their nests. Once you learn their twittering call, its easy to find them in flight above. Just look for "cigars with wings", usually in groups of at least 2 or 3 (sometimes many more), eating flying insects. To learn about these amazing birds and what YOU can do to make your home hospitable for these airborne bug zappers, check out the PDF handout available on this page.