From my visit to Lake Minsi when Joan and Rachel were visiting. These unique birdhouses are designed specifically for Purple Martins, the largest swallow here in the Northeast. Starlings usually take over Purple Martin nests, but these imitation gourds are designed so that the Martins can get in, but the Starlings can't due to their body shape. The Purple Martin population had dropped significantly in our area, but this "condo" and seven others just like it scattered around the edge of Lake Minsi have brought their numbers back up to a healthy level again. There is a constant amount of motion around them as you can see by the numbered of birds perched on this one.
Thank you everyone for the views, comments and favs! It's a unique design and great to see it's working.