Chimney Swifts?

My grandma made these gingerbread houses years ago 
and they were just given to me, so I brought them to school.  
The kids loved them!  One boy looked in the chimney and 
said, "Well!  There are no Chimney Swifts in this chimney!"  
That was pretty funny! In case you didn't know, Chimney Swifts 
are a unique bird that sleep in chimneys, but otherwise 
they fly all day long without stopping.  They eat, drink 
and bathe while flying!  That is such and interesting 
bird behavior!