About purple martins (see Tuesday’s post, “gourds and cans”): they have become entirely dependent on humans for nests in which to breed along the North American east coast.
Susie at pbmGarden sent me the link to a short (about 8 mins.) NPR documentary about the songbirds and the threats they face in the modern world (the fault is partly in Shakespeare).
Check it out here: “The Mystery of the Missing Martins” by Adam Cole
enclos*ure 
Wow, wow, wow! Amazing video!! Guess we need to get our martin houses that my dad made out of the basement!
Glad you enjoyed the video Cindy. Thanks for the mention.