do house wrens kill other birds

The House wrens have taken over my backyard, chasing out the chickadees and other cavity nesting songbirds. Two bird houses build for different species of birds, a welcome sign and a fake birdhouse have become nests for raising little wrenlets.

A couple of weeks ago while I was trying to take a nap in my backyard I was interrupted by some noisy baby birds calling for food. Hardly three feet away from my sleepy head I watched as a pair of house wrens made multiple trips in and out of the top hole in the “welcome” sign.

The pair must have thought the “welcome” meant for them, not for my guests that will brave my backyard.

The parents were very busy as they first delivered caterpillars by the dozen to their hungry kids. In a 30-minute period they delivered 22 creepy crawlers to the nest.

They also provided a diaper service for the growing family. After about every third food delivery, the adult would wait a couple of seconds and were given a white bag containing the kid’s soiled waste as they tried to kept their house semi clean. Bill Schiess, EastIdahoNews.com

Last week I noticed the soft food had been replaced by crunchier grasshoppers and beetles. Even a stinkbug was delivered and I wondered what that tasted like. But no, I will not try one. Two days after the food change the young were pushed out of the nest and took up residence is a pile of wood where they are being taught how to fend for themselves.

The female became a working single mom and it appeared that she was joined by another female with her brood as there were about 11 young with two adults living in the wood pile. Grasshoppers are being consumed by the dozens and since most of those insects cannot fly yet, the young wrens are fast learning self-sufficiency from the working moms.

Meanwhile back at the nest, the male had found a lovely female and after a few modifications to the nest she is rarely seen, while he spends a lot of time perching on top of the sign chimney. Occasionally he will bring in some morsel of food and disappear into the nest. Bill Schiess, EastIdahoNews.com

House wrens are notorious bullies, especially the males. The males start building several nests to allow a female to choose one and if another cavity nesting bird, like a chickadee has already started nesting, they will drive them out and destroy the nest.

Now don’t feel too sorry for the abandoned female for after a week or two the stronger and smarter kids are on their own. The others have been eaten by wild cats or other predators and the female may move to the territory of another male to raise another brood.

I really don’t mind having these aggressive little buggers around as they live on bugs. I don’t have to feed them and they do not eat my berries, but they eat a lot of insects that are after my garden.

In fact, I may make a few more nests. I just hope they will leave my tree swallows alone as they are my mosquito control machines and I want them around. Bill Schiess, EastIdahoNews.com Bill Schiess, EastIdahoNews.com

There were roughly 11 children and two adults living in the wood pile when the female, who had become a working single mother, appeared to have been joined by another female with her brood. Numerous grasshoppers are being devoured, and since the majority of those insects are still too small to fly, the young wrens are quickly picking up self-sufficiency from their working mothers.

I noticed last week that the crunchier grasshoppers and beetles had taken the place of the soft food. I was curious to taste the stinkbug that was delivered. But no, I will not try one. The young were forced from the nest two days after the food was switched, and they made their home in a pile of wood where they are being taught self-sufficiency.

Now, don’t feel too bad for the abandoned woman because the more capable and intelligent children will be left on their own after a week or two. The female may relocate to the territory of another male in order to raise another brood after the others were devoured by wild cats or other predators.

The parents were incredibly busy when they first gave their hungry children dozen caterpillars at a time. They delivered 22 spooky crawlers to the nest in a half-hour.

House wrens are notorious bullies, especially the males. The males begin constructing multiple nests so that a female can select one; if a chickadee or other cavity nesting bird has already begun to build a nest, the males will drive the other bird out and destroy the nest.

Perhaps it would be better if the bird waited its turn with grace and patience. But evolution rarely rewards patience. Indeed, House Wrens are fiercely impatient across the board. A male House Wren will frequently entice a second mate to relocate to a nest site on his property while the first mate is still caring for their clutch. Alternatively, he might sneak off to court the female on the territory of a nearby male and then destroy her eggs or young, forcing her to lay new eggs (his eggs) in their stead. And a man may bravely try to seize a territory by force if he does not already own one. Occasionally, the usurper is successful in forcing the native male to leave, taking his mate, and killing her eggs or young, forcing her to start over. The most successful males are the fiercest ones, and they pass on their fierce genes to their progeny.

At the time, some ornithologists wrote Sherman off as overly emotional—to which she countered that they were the emotional ones, too attached to their little brown birds to see them for the monsters they really are. “They are fond of their bird and are angry when the truth is spoken about it,” Sherman wrote in The Wilson Bulletin in 1925. “They act precisely like the parents of vicious children, refusing to believe the evil things their darlings do.”

Sherman, though, remained unpersuaded. She even went so far as to include a clause in her will prohibiting her backyard wrens from reproducing on her homestead even after her death. However, despite her campaign, the species is currently one of the most common songbirds in North America—undoubtedly aided by the same opportunism that Sherman found to be so morally repugnant. At least in terms of ecology, the House Wren appears to be doing something right.

When Althea Sherman in Iowa started to notice House Wrens building nests in her backyard in the early 1900s, she was thrilled. House Wrens are opportunistic nesters that will make their home in almost any empty crack or crevice they can find (a House Wren family is shown nesting in an old hat in an illustration by John James Audubon). Over the course of the following few years, as Sherman hung birdhouses in her yard, more wren tenants eagerly filled the vacancies. Ten pairs of them were once nesting on the property and raising a minimum of five chicks a season. Sherman, an aspiring ornithologist and artist, painstakingly documented the birds’ meetings, arguments, courtships, and challenges as parents throughout this time.

However, the wrens kill for survival rather than for retribution. There is intense competition among cavity-nesting birds, particularly for those that are unable to make a home for themselves, such as the House Wren. It needs to find an already-existing hole to make its nest; if one isn’t available, it will take whatever necessary action to live and procreate.

FAQ

Are wrens aggressive to other birds?

Territorial Trials Territorial House Wrens even attack the open-cup nests of species such as the Gray Catbird and American Robin. Larger birds readily chase House Wrens, which suggests that they recognize the threat the smaller birds pose.

Do wrens kill other baby birds?

House Wrens, Troglodytes aedon. are notorious for destroying clutches of other birds, including those of conspecifics. The destruction usually involves pecking holes in eggs and removing the soft lining from the nest cup; ifsmall nestlings are present, they may also be killed (Kendeigh 1941).

Are House Wrens good or bad?

These tiny birds can be aggressive, even towards much larger birds. It’s not uncommon for House Wrens to actually scare birds off after nests have already been built. It’s hard to believe these tiny little songbirds have such a big bite!

Do wrens raid other birds nests?

And indeed, over the last century, several studies have confirmed Sherman’s observations: Wrens will puncture the eggs of bluebirds, woodpeckers, nuthatches, sparrows, chickadees, swallows, Bobolinks, and warblers, and occasionally take over their nests.