What a great find not only for garden decor but I'm sure the Wren's will find it a very fitting home too!
Over the years I've seen Wrens build nests in all sorts of spots! Last year a pair of Carolina Wrens built a nest at the corner of the house wedged between the house and the AC Unit. Unfortunately a critter (likely a snake) got to the eggs before they hatched; one day I found all but one egg missing entirely and the next day the remaining egg was broken and empty; not broken like it had hatched but like something had pierced it a few times and cracked it open .
Before downsizing when we retired, I had a large collection of decorative birdhouses. I donated loads of them to a thrift store but kept a few and sat them outside. They didn't hold up long in our Florida humidity but this is one I sat on the brick ledge outside the bedroom window about 3 years ago and it was used by a pair of Wrens to raise a brood.
The nest isn't visible in this old photo but a pair of wrens built a nest in this fern basket.
25 or so years ago, one of my nephews gave me 2 Purple Martin Condos and my husband mounted them on poles in different parts of our property. We never attracted Martins but the Wrens used both of them every year for nesting!