While out on the patio today, I was constantly serenaded by the boisterous song of a house wren.
Later I noticed it was constantly busy carrying great mouthfuls of some stick-like material into a nest box. It is a strange nest box that a friend made some years ago and brought to me to try it out. It is supposed to attract swallows because the entrance hole is in the bottom of the box, but from the day I put it up, it has been used by house wrens every year.
If any swallows ever looked at it, the wrens never gave them a chance to become serious about it. The house wrens arrived earlier than the violet-green swallows do, so they are usually well entrenched before the swallows arrive. My yard is too far from any body of fresh water for the tree swallows to be interested in it, so my bottom-hole swallow box is well established as wren territory.
House wrens have been a part of my spring ever since I was so small that my mother had to lift me up to see into the nest. Along with chipping and song sparrows, they nested in our yard every year, and I always knew where all three of these birds were nesting. I watched them feed their young and said good-bye to them each fall.
They were then and still are a sign that spring has finally arrived. I heard the house wren singing for the first time this year in late April. They may return as early as late March in the warmer regions of metropolitan Denver but usually do not come up into the mountains until we have warmed up a bit.
Just a little smaller than a chickadee, they have a loud bubbling song that can be heard easily. By nesting in yards, they manage to escape most predators other than house cats. They are cavity nesters and will use any small cavity for a nest.
They are well known for nesting in strange places. I had one nest in my clothespin bag one year, and there are reports of their nesting in many nest boxes, garbage cans, tea pots, flower pots, the bottom of large bird nests, such as hawks, etc., in the pockets of scarecrows, old boots or shoes, yard pumps, etc.
The males establish a territory by singing and are then very busy building or starting nests until the females arrive about 10 days later. He attracts any female that wanders into his territory and presents her with up to half dozen nest choices.
She chooses which one she wants and completes the nest. The male usually constructs the main nest by filling the cavity with sticks, leaving a passageway to the rear. The female completes the passage way and builds a cup at the rear, which she lines with soft grasses, feathers, plant down, etc., in which she lays her eggs.
An average clutch is five to seven eggs but they may lay 12 or more. Incubation is usually about 13 days, but it may vary depending upon the temperature. Once the young leave the nest, they usually do not return but they’re still fed by the adults for 12 to 13 days until they learn to find their own food.
The feeding instinct is so strong that wrens will feed almost any young bird they see with its mouth open. Females almost always have a second brood, sometimes with the same mate and sometimes with another.
She often starts incubation of the second clutch while the first clutch is still being fed by the male. After the young are on their own, they become more secretive and may still stay around into autumn, but they are no longer singing and are not easily found. Their song is so loud in the spring and summer that they are found by it. The Chippewa Indians’ name for the wren actually means, “a big noise for its size.”
The controversy over wrens comes from the fact that they often destroy other bird nests or eggs to have a nesting cavity for themselves, which we judge as bad, especially if it is a bluebird’s nest, which is destroyed, but they eat a very large number of insects, almost all of which are enemies of our crops and gardens, which we consider as good.
I think their cheery song is well worth having them around, but Bill couldn’t find anything good to say about them after they destroyed a Williamson’s sapsucker’s nest that he and a friend had been photographing.