House wren

This feisty little songbird has the greatest range of any native songbird in the western hemisphere. It is easy to find and can be found from central Canada all the way down to the tip of South America.

Five Amazing House Wren Facts

• These tiny birds are not above puncturing the eggs or kicking out the hatchlings of other birds that nest in cavities. They even do this to other wrens whose eggs they find in their territory.
• Females, as well as males, sing competitively. Females who sing the most lose less of their eggs to ovicide.
• A person who wants to lure house wrens with a nest box should paint it red or green, since these seem to be the wren’s favorite colors.
• House wrens use all manner of materials to build their nests, including paper clips, wires, staples, tacks, nails, hooks, fasteners, and bobby pins. The cup itself is lined with softer materials such as grass, hair, lint from a clothes dryer, and feathers.
• House wrens have a lifespan of as long as seven years, though seven years is considered unusual.

Where To Find House Wrens

You can often find house wrens in your backyard, as they are tolerant of humans and pollution and have benefited from urban development that fragments forests into smaller green areas. They’re also found in the open woods, brush, thickets, near rivers, and in savannas, especially in the southern states.

Classification and Scientific Name

The house wren’s scientific name is Troglodytes aedon. Troglodytes is from the Greek words trogle, which means “hole” and dyein, which means “dive in.” This refers to the wren’s habit of nesting in cavities and diving into holes and crevices in search of food or shelter. Aedon is the name of the queen Zeus changed into a nightingale.

Troglodytes aedon has at least 30 subspecies, and some scientists believe that some of these subspecies may be separate species altogether.

Appearance

House Wrens are tiny, stocky birds that are shades of brown all over, though they have a barely noticeable white stripe above their eyes. They are 4.3 to 5.1 inches long and weigh 0.35 to 0.42 ounces with a 5.9-inch wingspan. The plumage of male and female birds is alike, but males may be a bit larger. The beak is long for the body and has a slight curve, and when the birds perch, they hold their short tails up. The feet are big for the bird’s size, and the legs are pinkish.

Behavior

Despite their size, house wrens are bold and even belligerent creatures. Most of the responsibility for defending a territory goes to the male, and he will confront an intruder by dropping into a crouch, lowering his wings, fanning out and lowering his tail, and raising his hackles. House wrens are notorious for destroying the eggs and nestlings of other birds that try to nest in their territory, even eggs and nestlings of conspecifics. Females take on other creatures that try to invade the nest, even if they’re larger. If a pair finds a nest inside their territory, they’ll fill it up with sticks so that it can’t be used.

House wrens are diurnal, which means they’re active during the day. They hop when they are on the ground and do not fly high, though their flight can be fast and steady. This little songbird also has a great repertoire of songs and calls. Scientists have counted at least 130 of them. Males can sing for 10 minutes at a time, and they sing a quiet “whispering song” as they mate. They can be said to be humming this song, for they don’t open their beaks as they sing. Biologists believe this is to keep the location of their mate a secret from other males.

Migration Pattern and Timing

House wrens who live in the northern part of their range migrate to the southern United States and Mexico for the winter, typically starting in mid-September and continuing through early November. Once there, they’ll live in thickets and brush. They’ll return in late winter or earliest spring through early May. The males arrive first to scout for nesting sites.

The House Wren Alarm Call

The house wren gives an alarm call when it senses large predators in the area. It is a series of staccato cheeps or chittering.

Diet

House wrens are insectivores and forage for caterpillars, grasshoppers, beetles, bugs, flies, and crickets in the lower branches of trees or on the ground. Wrens will also take spiders, millipedes, and insect pests such as cabbage worms, tent caterpillars, ticks, and locusts. They also eat snails, as they need the calcium from their shells.

Predators and Threats

Being a small bird that often flies and nests low to the ground, the house wren is part of the diet of a good number of predators. These include the ever-present pet cat, rats, foxes, opossums, raccoons, squirrels, snakes, and birds of prey such as kites and owls. Woodpeckers, whose eggs may be destroyed by wrens, also avenge themselves on the little birds. But the pugnacious little songbird doesn’t hesitate to counterattack. It will strike the predator with its beak and claws while giving its alarm call.

The nests of house wrens are somewhat filthy even before the eggs hatch. They are full of mites and bacteria and may even contain blowflies, even as the parents are careful to remove fecal sacs, dead chicks, and dud eggs.

Reproduction, Babies, and Lifespan

When the males return from their wintering grounds, they start to look for suitable nest sites. These are usually in cavities or holes, and they can include not just empty woodpecker nests and nest boxes but abandoned items of clothing, gourds, and flower pots. He’ll start to construct nests in several places, then sing loudly to get the attention of a female. If she’s interested, she will finish the nest. The male continues to sing after he’s mated, but not as loudly.

The house wren’s breeding season falls between April and September, and most eggs are laid in mid to late May. They are oval, the size of a dime, brown, and speckled. Wrens are monogamous for one breeding season. If there are two broods in a year, they will most likely not mate with the birds from the first brood. Once in a while, a male will mate with a second female, but these broods are less successful. This is because he’s too busy tending to the chicks he had with the first female to help with the second. The second female not only doesn’t have a helper, but if she leaves the nest to find food, her babies are subject to predation or downright infanticide by other unmated wrens.

After finishing the nest, a female lays between four and eight eggs. They are incubated for 12 days, and the chicks are blind and helpless when they hatch. Though they’re brooded by the female, they are fed by both parents. They get their first feathers 15 to 17 days after they hatch and, one by one, leave the nest. Still, their parents feed them for about two more weeks.

After the wrens establish their own nests and start incubating eggs, the ovicides (egg destruction) and nestling murder go way down. Scientists believe this is so house wrens won’t accidentally kill their own children like Aedon!

House wrens are able to breed when they’re a year old and can have a lifespan as long as seven years.

House Wren Population

The population of house wrens is estimated to be around 190 million individuals. The songbird’s conservation status is Least Concern, and its population seems to be stable.