In Defense of House Wrens:

The Great Wren Debate Re-revisited

 by Karen Lippy

I take up my pen with trepidation because I know I am about to do battle against decades of demagoguery of the house wren. Perhaps more ink has been spilled across the page in vitriolic hatred of this little bird than even the house sparrow. I know, because I have spent the past few days perusing the archives of bluebird-l and reading comments about wrens. One must look hard and long through these writings to find a single favorable comment about the bird.

Aletha Sherman wrote the following words: "If, when a felon is on trial for high crimes and misdemeanors, he is confronted by numerous eye-witnesses who are trustworthy and fully competent to testify; if by their evidence it is proved that for upward of twenty-five years, he has been seen committing the most flagrant crimes against his neighbors; if the depositions of these expert witnesses have been spread upon the public records and printed in volumes accessible to every one, it would appear that they ought to demand, for the good of our country, that the felon be sentenced and that the sentence be executed without dangerous delay." In the American justice system, the accused has a right to be defended by counsel. Since no wiser and more qualified person has stepped into this breach, I feel it my duty to do so. Barbara Boyle's article recounting Aletha Sherman's writings against the wren encapsulates all of the complaints brought to bear against house wrens. Let me attempt to refute those claims point by point.

Aletha Sherman was recognized in her day for being a self-taught biologist who studied and wrote about birds. Her writings were included in the scientific journals of the day. She gained the grudging respect of her peers, mostly men. However, she committed the greatest sin of a true scientist with the wren--she became emotionally involved in the lives of her subjects. That involvement colored her study of the wren and skewed her translation of the results.

First, wrens not only expanded their territory because of the nest boxes provided for them, but because the national landscape had forever been changed by expanding human populations. Bird species of all varieties were affected by this change--many declined, some expanded their range. The house wren began pioneering into Aletha's woods. At first, with only a few wrens, things went well. As the population grew, competition became fierce for nesting cavities. But not one wren ever showed up in Aletha's woods with a premeditated plan to exterminate all other species in the area. The birds were incapable of forming such a plan. Aletha judged the wrens not as a member of the bird community, but by her moral standards and found them wanting. A response from a contemporary of the day replied to the effect--"tried in the court of man, the wren is found guilty. But tried in the court of his fellow wrens, his behavior is exemplary." (God forbid that other species should ever be allowed to hold us to their standards and punish us as they see fit!)

She was not alone in attributing human characteristics to wildlife. Ben Franklin found the eagle "a consumer of carrion and a wanton coward". Men climbed mountain peaks in spring and fall with guns to kill migrating hawks because these 'evil' birds killed songbirds and game such as rabbits and squirrels which they wanted for their own table. Bears, wolves, cougars and all other predatory species were looked upon with the same scorn and eliminated without conscience, changing forever the environmental balance. Aletha saw the wren invasion of each nest as a total loss of opportunity for breeding success of the affected birds during that entire season. Not necessarily true! Birds are more adaptable than that--a fact that, for all her study of birds, she did not seem to recognize. Since most of the competition occurs soon after the arrival of wrens, it is generally early enough in the season for the bird with lost eggs or chicks to go elsewhere and try again. Thus, no serious lasting impact is caused to any particular species. Aletha's wrath turned against the wren and she took down her boxes, encouraging all she could persuade to do so as well.

Her crusade against the wren is still in full cry today. What happened when she took down the boxes? "The wrens then destroyed the families of Downy and Hairy woodpeckers, flickers, bluebirds, and others, securing the cavities for themselves.." The driving force of all living things is to procreate. If we remove the boxes or destroy the nest, the bird looks for another site. Every year, nest monitors do the same thing--remove wren nests as soon as they are placed in nest boxes, then become angry and discouraged when the wrens attempt to nest elsewhere. I am convinced that these monitors, not the wrens, are to blame for the majority of wren disruption.

Aletha and Barbara ascribe to the theory that all who disagree with them are "entirely ignorant of the destructive tendencies of House Wrens, or worse, those who admired the wren and would not allow their beliefs to be challenged". I offer a different perspective, not of ignorance, but from experience.
I began with the Codorus Bluebird Trail in 1984. At that time, we were encouraged to remove wren nests. As a beginning monitor, I did as I was told. The result was constant disruption by wrens for the entire nesting season. In 1988, I took over as coordinator of the trail. I changed this policy. We now allow wrens and all other species to utilize our nest boxes. And yes, it is dismaying to have a chickadee, titmouse, or bluebird thrown out. But wrens do not kill the adults as do house sparrows. The birds can go elsewhere to nest. Once the females arrive and select a nest site, we remove the dummy nests. This often takes a period of 2-3 weeks for the birds to settle down. If, after 3 weeks, the nest contains no eggs and the wren does not seem to be guarding the box, the "dummy" nest is removed. It generally doesn't take long for another species to claim the box. Weekly monitoring will keep you abreast of the dates activity begins. Wren disruption from this period on is generally minimal. And as we discontinued our interference with the wrens, their combativeness seemed to abate.

It appears that often wrens that have had success in a nest the prior year will remain close to that site in successive years, limiting disruption. Some years, the wrens seem more aggressive than others. Could it be that many of the dominant males have failed to hold their sites and the new territorial holders must assert their dominance by such aggression? I'm not sure. I only know that since we initiated this program wren numbers have held steady. They have not, as Miss Sherman was sure they would, eliminated all other cavity dwellers in the area. The following table lists bluebirds, tree swallows, house wrens, tufted titmice and Carolina chickadees fledged from 170 boxes:

Contrary to Barbara Boyle's statement, "The years between Miss Sherman's observations and now have provided more opportunities to prove her theories and it is so.", no species mentioned as being in jeopardy of destruction by wrens has been eliminated solely by them. If wrens have not managed to do so in 75 years in spite of expanding their range, we should not assert that the vilification of an entire species deserves any merit. In fact, if Miss Sherman had monitored enough nest boxes for a length of time, she may have learned that bluebirds, tree swallows and other cavity nesting species also practice the habit of removing eggs and chicks of previously nesting species. I concede that not as frequently as house wrens, but the wrens have been 'trained' for years to utilize this survival tactic to the utmost.
The problem lies not with the wrens. Boxes placed in brushy areas and wooded edges will primarily be utilized successfully by wrens. Boxes placed in more open habitat should be more successfully utilized by tree swallows and bluebirds. Boxes deeper in wooded areas allow more success for other species. But the adage "Never say NEVER and never say ALWAYS" holds true in all cases. You can no more teach wrens not to utilize boxes placed in their appropriate habitat than you can force a round peg into a square hole.

For many years I have heard it said that you can remove wren sticks as long as they have not laid eggs. If you do so before the hen has arrived to choose her nest site, you are interfering with the nesting cycle of these birds. If the intention is to prevent successful nesting of a protected species, it would seem we are seriously bending the intent of the law. If we elect to choose which laws we will obey, doesn't that put us in the same category with those who stood on mountaintops and shot those passing 'bad' hawks? As stewards of nest box trails, shouldn't it be our duty to obey all laws (including those we don't agree with), such as protecting ALL native species?

I stand before you an unashamed admirer of house wrens. I have presented the facts to the best of my ability. Gentlemen and gentlewomen, the fate of the house wren is in your hands. You check the ballot by the manner you receive your first house wren of spring.

Posted with permission and slight modification for this format.

Maps