House Wrens (Troglodytes aedon) are aggressive and adaptable nestlers. They will build their nests in just about any container left out in the open: flowerpot, empty tin can, a pocket of an old coat, as well as tree holes and nest boxes.
They often bully other birds, ejecting them from nest sites and even destroying eggs and young. Two broods a season are raised. The male frequently changes partners in mid-season, so that while his original mate is still feeding chicks, another female is sitting on new eggs.