House Wren Mating Habits
The House Wrens mating habits are very complex with the male possibly pairing with two female birds at the same time or mating with one at the start of the season and then mating with a second (or even third!) female as the season passes.
The House Wrens mating habits are very much intertwined with the marking of the territory since they are very territorial. As soon as the male wren arrives it isolates itself and marks off its chosen territory by singing a territory song. The territory song serves as an announcement to other birds that the area is already occupied and tells them to stay away. The song also has another purpose, which is to announce to female birds the presence of the male bird. It serves to entice female birds into the male wrens territory in hopes of mating with the female bird.
The territory song turns into a mating song when a female wren arrives at the scene. The change in the male wren while singing is noticeable since it sings the territory song rather mechanically until it spots a female bird wherein it starts singing in a visibly more enthusiastic manner. If another male house wren has a nearby breeding territory the two male wrens launch into a singing competition by singing even more energetically to entice the female wren into choosing their territories.
After the female wren arrives in a territory the wrens, since they are songbirds after all, launch into earnest courtship starting off with a vast repertoire of songs and call notes sung to each other. Both birds exhibit excitement (although irritation as well) by quivering their wings. The male birds tail also starts tilting upwards when excited. The longer the courtship song progresses the higher the male birds tail tilts. During the time of copulation the male wrens tail actually tilts forward or at least assumes a vertical position.
The building of the nest is also part of the House Wrens courtship ritual wherein the male starts building dummy nest even before the female arrives. The female chooses the final nest to be used. Sometimes while the female bird is incubating the eggs the male builds an extra nest and sings the courtship song. This is how the male House Wren sometimes gets another mate.