House Wren
| Scientific Name | Troglodytes aedon |
| Survival Strategy | Medium-distance migrant |
| Arrival in Upper Midwest | Late April to early May |
| Departure | September to early October |
| Destination | Southern US, Northern, and Central Mexico |
| Conservation status | Least Concern |
Spring
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.
Summer
If a house wren attempts a second brood, it takes place in late June through early July.
Fall
House wrens leave the Upper Midwest in September through early October. Collisions with communication towers suggest that they migrate at night.
Winter
Their winter range includes the Southern US along with Northern and Central Mexico.
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Behavior
Egg-destroying Behavior
House wrens are territorial and will peck open the eggs or toss out the nestlings of other cavity nesters. They are thought to be a significant reason for nest failure among bluebirds, tree swallows, and chickadees. Breeding Bird Survey data shows that the house wren population in North America is on the rise, increasing 1.6% per year.
House wrens are native songbirds, making it illegal to kill them or interfere with their nesting activities. Boxes for bluebirds or tree swallows should be kept away from woody areas to discourage the wrens’ territorial behavior.
Mite control
House Wrens collect spider egg cases and bring them inside the nest cavity. Spiders hatching from these egg cases may help reduce the population of mites in the nest.
Physiology
It Takes Guts to Migrate
Very little is known about how the physiology of the house wren changes before or during migration. However, one study found that after being exposed to cold temperatures, house wrens increased the length of their small intestines. A longer intestine would increase the efficiency of the digestive system by extracting more of the nutrients from its prey (Think, better gas mileage).
Diet
House wrens are insectivores. Their diet includes grasshoppers, moths, caterpillars, beetles, and other small invertebrates.
Lifespan and Mortality
The average lifespan of a house wren in the wild is seven years, and bird banding data showed that one individual lived to be nine years old.
Predators
House wren eggs or nestlings are seen as an easy meal by predators such as domestic cats, raccoons, mice, tree squirrels, and woodpeckers. Other house wrens will destroy eggs and toss out nestlings.
Cats, foxes, falcons, hawks, and owls are common predators of adult house wrens.
Climate Vulnerability
Climate models indicate the range of the house wren will likely be shifting farther north.
Never stop learning
Etymology
The house wren’s scientific name is Troglodytes aedon.
“Troglodytes” is from Latin trōglodyta, which means “cave-dwelling people.”
In Greek mythology, Aedon was the wife of Zethus, who changed her into a nightingale.
References
| Johnson, L. S. (2020). House Wren (Troglodytes aedon), version 1.0. In Birds of the World (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.houwre.01 |
| Brown, J. 2001. “Troglodytes aedon” (On-line), Animal Diversity Web. Accessed October 24, 2021 at https://animaldiversity.org/accounts/Troglodytes_aedon/ |
| Klimkiewicz, M.K., R.B. Clapp, and A.G. Futcher, 1983. Longevity records of North American birds: Remizidae through Parulinae. Journal of Field Ornithology 54: 287-294. |
| House Wren | Audubon Field Guide https://www.audubon.org/field-guide/bird/house-wren |
| Dykstra, C. R., and Karasov, W. H. (1992). Changes in gut structure and function of house wrens (Troglodytes aedon) in response to increased energy demands. Physiol. Zool. 65, 422–442. doi: 10.1086/physzool.65.2.30158261 https://www.journals.uchicago.edu/doi/pdf/10.1086/physzool.65.2.30158261 |
| House Wren- Climate Change Bird Atlas https://www.fs.fed.us/nrs/atlas/bird/7210 |
| Journey North: Wren Facts https://journeynorth.org/tm/spring/WrenFacts.html#House |