Wrens will eat 2,000 bugs in their first two weeks of life. Most wrens have anywhere from four-eight babies per brood and will have three-four broods per nest per summer. That is a lot of bugs consumed and off your plants. House Wrens eat beetles as well. Right now my Wren houses are in my Rose garden because I have such an issue with Japanese Beetles in the summer. It is handmade out of cedar and stained with Tung oil to protect it from the weather. It will grey over time like lovely barnwood. Vents on the side make it easy to clean when needed.