House wren known as the 'nonstop nester'
While many birds curtail, so to speak, their nesting efforts during the summer, the house wren does not. They just keep going. Let's take a closer look at this clamorous, nonstop nester.
This diminutive bird is only 4.75 inches from stem to stern, with a six-inch wingspan. From afar, a wren is uniformly brownish gray, a classic LBJ, or little brown jobbie.
Upon closer examination, you'll note that the throat and chest are light gray while the head and back are a consistent shade of brown.
A wren's most distinguishing characteristic is its tail. It is finely barred in black and almost always cocked upward at a nearly 90-degree angle to the bird's back.
It is hard to believe that such a small bird can project such a loud and complicated call, a call that defies phonetic description. The songs usually last from 1.5 to 2.5 seconds, but that's just the beginning. In the spring, from the time the male migrates back to the nesting territory until the eggs hatch, the wren repeats his song 100 to 600 times per hour every morning. He's one busy little vocalist.
What amazes me is that "this song-ball of tongues," as described by poet Ted Hughes, is able to keep singing while he is busy building not just one but many nests.
House wrens will build their nests in almost any enclosed space. A partial list of nesting sites includes: nest boxes, mailboxes, flowerpots, drainpipes, hats, cans, teapots, folded awnings, old boots, fish creels, parked cars, and in the pockets of pants hung out to dry.
Wrens also use natural cavities such as old woodpecker holes and rock crevices.
Two wren nesting studies found that house wrens prefer nest boxes with old nests in them. So much for cleaning the next box out each spring.
Let's talk about the nest or, should I say, nests. When the males return, they can build six or so extra, or "dummy,," nests in every available cavity in their half-acre sized territory. Wren nests are largely composed of sticks with the male adding more than 400 or as few as 10 sticks to his dummy nests.
These extra nests are model homes that the male shows to the discriminating female. Once she selects her favorite model and pairs with her mate, further nest modifications, such as lining the nest cup with soft materials, becomes her responsibility.
They start laying their first clutch of six to eight eggs in early May. By early July, most wren pairs will be working on a second clutch of four to six eggs.
Invertebrates eaten by wrens include grasshopper, leafhoppers, beetles, caterpillars, earwigs, snails, and ticks. In many cases, the wrens are dining on both the larval and adult forms of insects. Remember, they're not just feeding themselves, but hungry nestlings as well.
• Mark Spreyer is executive director of the Stillman Nature Center in Barrington. Send your comments or questions to him at firstname.lastname@example.org.