A tree frog moved into my wren house. He's enjoying the view from the front porch.
The Wren house is a hollow plastic ball that I drilled a 1 1/4 inch entry hole and drainage holes. I've tried wood Wren houses but Sparrows always peck at the entry hole until it's big enough for them to fit in....the Wrens are chased away. The plastic ball has worked. A Wren couple moved in last Spring.