Yup, we have wrens. Babies in both nest houses — and the bluebird site says that when wrens find your houses you have wrens forever. They are aggressive towards other cavity nesters: bluebirds, chickadees… I bought another bluebird box to put up.. supposed to put them in clearings, not close to woods and brush — difficult here.
wren chicks - who could resist. So what if they are not bluebirds. Besides, one has to admire the tenacious parents.. it's a jungle out there in the prairie.