Your post reminds me of the bat tower that was built in the Florida Keys. Back in 1929 a bat tower was built to help house bats in hopes of helping with the bad mosquito population in the keys (that we still have). They story goes that the bats were released into the tower and promptly flew away never to be seen again. The bat tower stood all these years and was eventually added to the register of historic places. In 2017 Hurricane Irma knocked the bat tower over. My understanding was only 14 bat towers of this design were constructed and only 2 remain standing.