In late April through early May, house wrens return to their breeding range and start their first brood. The male house wren arrives first and marks its territory by building crude dummy nests. Wrens nest in natural cavities and human-made nest boxes, as well as any crevice they can find, such as old boots, abandoned hornet nests, or farm machinery. The female completes the nest construction at one of the dummy nest sites. She will lay one egg per day until she has a clutch size of 5-8 eggs. Incubation is by the female only and lasts for 12–13 days, depending on the temperature. The hatchlings fledge at about 17 days, and parental care continues for another 13 days.