When nesting, the House Wren typically builds their nest into small cavities and makes their bed from a variety of twigs, grasses, feathers, hair, string and discarded plastic amongst other items. They typically lay a clutch of between three and 10 eggs at the rate of one egg per day.
Once the eggs are laid the incubation period lasts from between nine to 16 days before the young wrens start to hatch.
Problems can occur however if the temperature outside the nest box goes above or below certain temperatures. If a nest box is warmed above 106 degrees Fahrenheit for around an hour, the young birds in the eggs will begin to die.
Furthermore, if the nest suffers from temperatures lower than 65 degrees for more than a day, the chicks in the eggs can also perish.
Given these factors and dependent upon how many eggs are in the nest and the ambient temperature at the time, a House Wren's egg can take as little as nine or 10 days to hatch from being laid, or can take as long as 17 days.
A nest containing more eggs generally will take longer due to the fact that the wren only produces one egg a day, therefore the more eggs a wren produces, the longer it will take to hatch them in the nest.
Once they have been hatched, the young chicks will typically spend between 15 to 17 days in the nest before they become fledglings and leave.