(This column was first published in the July 11, 2004 issue of The Buffalo Sunday News.)
One of the cheeriest songs heard around country homes is that of the house wren. Neltje Blanchan describes it well: "Like some little mountain spring that goes rippling along over the pebbles, tumbling over itself in merry cascades, so this little wren's song bubbles, ripples, cascades in a miniature torrent of ecstasy."
The presence of a pair of these energetic little birds in a yard can amuse and delight the meanest spirit. They are the developers of the bird world, each individual, whether male or female, frantically building homes in every niche it can find. A male may even continue to construct nests when his mate is incubating.
Wrens build in bird houses but they also construct nests in almost any available crevice -- in a tin can, a teapot or flowerpot, an old boot or shoe, a pump nozzle, the end of a hollow railing or the pocket of a scarecrow. They sometimes drive off, take over and reconstruct the nests of other birds -- even the hanging nests of orioles and the bank burrows of kingfishers. One observer reported on what must have been the most unusual pair, however. These wrens nested on the rear axle of a car that was used daily. When the car was driven, the wrens followed along. Remarkably, the eggs in this strange nest were successfully hatched and the resulting brood all fledged.
Another strange pair of wrens was observed raising young in two nests at the same time -- one in a gourd, the other in a birdhouse. They acted like a divorced couple, the male and female incubating and then caring for separate families.
The nesting materials are equally interesting. Twigs, feathers, leaves, twine, pieces of cloth, bark and weed stalks are often used but odd materials may also be found. An inventory of a single nest listed, among other things, "52 hairpins, 68 nails (large), 120 small nails, 4 tacks, 13 staples, 10 pins, 4 pieces of pencil lead, 11 safety pins, 6 paper fasteners, 52 wires, 1 buckle, 2 hooks and 3 garter fasteners." This pair of wrens could easily have stocked a flea market table.
When they build in birdhouses, they often face initial difficulty getting a longer stick through the small entrance hole, but these intelligent little wrens soon learn to turn the twigs lengthwise and, once they have mastered this method, they use the technique without hesitation.
The mating instinct of these feisty birds is obviously strong and occasionally it is extended to support for other species. For example, one house wren was seen bringing food to a pair of rose-breasted grosbeaks at their nest. The grosbeaks readily accepted the food, sometimes eating it themselves instead of feeding it to their young.
There is also a down side to wren behavior -- their frenetic activity too often turns to aggression. A journal article entitled "Down with the House Wren Boxes" found house wrens guilty of destroying the eggs or killing the young of other birds -- and bluebirds in particular. Indeed this is a serious problem, especially for those who care for trails of bluebird houses.
A few weeks ago I joined Steve Labuszwski in Nature View Park where we visited the dozen bluebird nest boxes he had built and set out. Unfortunately, none had been used by bluebirds; most were filled instead with the identifiable sticks of the far more feisty and opportunistic house wrens. (One produced something quite different. When Steve opened the box, a little white-footed mouse jumped out onto my chest and scampered down my leg into the underbrush. Unprepared for this surprise, I jumped even farther than it did.)
But many serious ornithologists come to the house wrens' defense. In particular their food is almost exclusively grasshoppers, beetles, caterpillars and spiders with over 95 percent of these invertebrates considered pest species. One economic ornithologist went so far as to argue that wrens are more beneficial than "most of the species whose eggs it occasionally destroys."
I suspect that some readers will have trouble with that argument, but we have come to accept predators like hawks and owls. We'll just have to put up with an occasional act of infanticide from these otherwise welcome neighbors.-- Gerry Rising