House Wren Courtesy of Terry Sohl

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The house wren (Troglodytes aedon) is a small brown native bird with a cocked tail and an attitude to match. Its outsized chattering is incessant during the breeding season. If you have a house wren nesting in your yard, you will know it.

If you set up a nest box hoping to attract bluebirds, chickadees, or purple martins, your guests might also include house sparrows or house wrens. All are cavity nesters. House sparrows were first introduced to the U.S. in 1852. These non-native birds out-competed other cavity-nesters, particularly the docile bluebird. In the 1920s and 1930s, inventive pioneers began to design and erect nest boxes specifically for bluebirds. Anyone who has volunteered to monitor these “bluebird trails,” has quickly learned about the competitive house wren.

While their preferred habitat is shrubby woodland edges, the house wren’s common name suggests adaptability. They like human conveniences and will stuff their twiggy nests into any handy hole or space. They do not excavate their own holes. J. J. Audubon’s drawing of a house wren shows nestlings begging from an old hat.

The house wren is a species of the western hemisphere. Some subspecies are called the Southern house wren and live their entire lives in South and Central America. Our house wren, often referred to as the Northern house wren, migrates to and from its wintering grounds in the southern tier of the U.S. and Mexico. Northern and Southern house wrens rarely meet.

The basics: House wrens are four to five inches long, brown above and lighter below, often with darker brown strips on wings and tail. Their coloration varies slightly by region. They eat insects and spiders. The cocked tail position, while fairly typical of the house wren, is the rule in its relative, the winter wren. They typically lay seven small, glossy white eggs so deeply speckled with reddish-brown that the white is almost obscured. They can have three broods a season in our area, giving them the potential of 21 offspring per year! Both parents feed nestlings and young. Males will often feed fledglings while the female gets right to work laying another clutch. They often return to their previous breeding grounds.

At one time, it was thought that house wrens were monogamous and “cute.” However, in a 1878 essay reprinted in A Treasury of Bird Lore, the author explains that the house wren “morals are not of the best” and that “two respectable old ladies took down their wren boxes when it was discovered some years ago that house wrens are likely to change mates in the middle of the season.”

According to Cornell’s Birds of North America Online, the house wren is probably the most studied perching bird in North America because of its affinity for human locales. Research on the house wren began in 1921 and continues to this day. Considering 88 years of study, it is noteworthy that the house wren has revealed so little of itself.

Perhaps European folk tales provide a clue, even though they describe the closely- related winter wren. The stories celebrate the little bird’s wily ways. In a contest for king of birds, as one tale has it, king is the highest-flyer. “The wren wins by riding on the eagle’s back, thus being the highest.” The version wherein the enraged eagle removes part of the wren’s tail, causing flight problems, explains why the wren is usually found on low branches or wires. In an opposite tale, where the king is the lowest flying, the clever bird wins by flying down a mouse hole.

Male house wrens arrive on their breeding grounds a few days before the females and begin transporting sturdy twigs about an inch long into a nest hole. Prior to egg laying, house wrens often prey on other birds’ nests and eggs. They go so far as to prick holes in eggs and remove them, one by one, from the nest, or remove nestlings, or remove nesting material, or simply build their nests atop eggs or young. While the logical hypothesis is that this reduces competition for food in the breeding grounds, the value of this behavior remains a mystery to humans.

Males don’t restrict themselves to one nest, instead making dummy nests in several desirable holes. They then sing to attract a female, who inspects the nests. When she selects a mate and a nest, she lines the low, back portion of the nest with soft grasses. The basis upon which the female chooses architect and architecture is unknown, as is the benefit to the male in expending the energy in so many construction projects.

In addition, the males may insert spider cocoons among the twigs, giving the appearance of little white cotton balls sprinkled throughout. Researchers hypothesized that the purpose is decorative and would appeal to females, but studies show that females are unimpressed. Researchers hypothesized that the emerging spiders consume mites that might interfere with nestling health, or that spiderlings serve as food; neither hypothesis was confirmed. According to a 2005 study from Normal, Illinois, males who add cocoons are apt to breed later and thus have fewer offspring. The study concluded: “Why males add cocoons during nest building is an enigma.”

House wrens delight and intrigue scientist and layperson alike. Their energetic antics and lively trill in our leafy suburb are a sure sign of summer.

If you set up a nest box hoping to attract bluebirds, chickadees, or purple martins, your guests might also include house sparrows or house wrens. All are cavity nesters. House sparrows were first introduced to the U.S. in 1852. These non-native birds out-competed other cavity-nesters, particularly the docile bluebird. In the 1920s and 1930s, inventive pioneers began to design and erect nest boxes specifically for bluebirds. Anyone who has volunteered to monitor these “bluebird trails,” has quickly learned about the competitive house wren.

While their preferred habitat is shrubby woodland edges, the house wren’s common name suggests adaptability. They like human conveniences and will stuff their twiggy nests into any handy hole or space. They do not excavate their own holes. J. J. Audubon’s drawing of a house wren shows nestlings begging from an old hat.

The house wren is a species of the western hemisphere. Some subspecies are called the Southern house wren and live their entire lives in South and Central America. Our house wren, often referred to as the Northern house wren, migrates to and from its wintering grounds in the southern tier of the U.S. and Mexico. Northern and Southern house wrens rarely meet.

The basics: House wrens are four to five inches long, brown above and lighter below, often with darker brown strips on wings and tail. Their coloration varies slightly by region. They eat insects and spiders. The cocked tail position, while fairly typical of the house wren, is the rule in its relative, the winter wren. They typically lay seven small, glossy white eggs so deeply speckled with reddish-brown that the white is almost obscured. They can have three broods a season in our area, giving them the potential of 21 offspring per year! Both parents feed nestlings and young. Males will often feed fledglings while the female gets right to work laying another clutch. They often return to their previous breeding grounds.

At one time, it was thought that house wrens were monogamous and “cute.” However, in a 1878 essay reprinted in A Treasury of Bird Lore, the author explains that the house wren “morals are not of the best” and that “two respectable old ladies took down their wren boxes when it was discovered some years ago that house wrens are likely to change mates in the middle of the season.”

According to Cornell’s Birds of North America Online, the house wren is probably the most studied perching bird in North America because of its affinity for human locales. Research on the house wren began in 1921 and continues to this day. Considering 88 years of study, it is noteworthy that the house wren has revealed so little of itself.

Perhaps European folk tales provide a clue, even though they describe the closely- related winter wren. The stories celebrate the little bird’s wily ways. In a contest for king of birds, as one tale has it, king is the highest-flyer. “The wren wins by riding on the eagle’s back, thus being the highest.” The version wherein the enraged eagle removes part of the wren’s tail, causing flight problems, explains why the wren is usually found on low branches or wires. In an opposite tale, where the king is the lowest flying, the clever bird wins by flying down a mouse hole.

Male house wrens arrive on their breeding grounds a few days before the females and begin transporting sturdy twigs about an inch long into a nest hole. Prior to egg laying, house wrens often prey on other birds’ nests and eggs. They go so far as to prick holes in eggs and remove them, one by one, from the nest, or remove nestlings, or remove nesting material, or simply build their nests atop eggs or young. While the logical hypothesis is that this reduces competition for food in the breeding grounds, the value of this behavior remains a mystery to humans.

Males don’t restrict themselves to one nest, instead making dummy nests in several desirable holes. They then sing to attract a female, who inspects the nests. When she selects a mate and a nest, she lines the low, back portion of the nest with soft grasses. The basis upon which the female chooses architect and architecture is unknown, as is the benefit to the male in expending the energy in so many construction projects.

In addition, the males may insert spider cocoons among the twigs, giving the appearance of little white cotton balls sprinkled throughout. Researchers hypothesized that the purpose is decorative and would appeal to females, but studies show that females are unimpressed. Researchers hypothesized that the emerging spiders consume mites that might interfere with nestling health, or that spiderlings serve as food; neither hypothesis was confirmed. According to a 2005 study from Normal, Illinois, males who add cocoons are apt to breed later and thus have fewer offspring. The study concluded: “Why males add cocoons during nest building is an enigma.”

House wrens delight and intrigue scientist and layperson alike. Their energetic antics and lively trill in our leafy suburb are a sure sign of summer.