Wednesday, December 12, 2012

Behold the Wren’s Nest, for it is Compact!

Wrens are noted for their secure building practices! They seem to pack a lot of refuge into a small cavity and tamp it down enough that the material just doesn’t want to disintegrate. Contrast that to a Dove’s nest that seems like four sticks laid on a fork in my Holly tree.

I have a canopy over my basement door (called a garden level entrance in architecture parlance) where the roof is corrugated metal. In the rails that support the roof, which double as rain gutter, the wrens routinely attempt to build nests. Of course, depending upon how often I go in and out of the door, I either chase them off their construction site or they get invested in a new nest and stick it out. What has always amazed me is that when it rains surely the flood waters must rise a bit and I can’t but help wonder how much water in their bedroom will they tolerate.

One other time I was away from home for couple of days during nesting season (wren nesting season really seems to run for quite some time) and they had started a nest above my porch light next to my side door into the house, under the porch ceiling. I took a broom and destroyed the nest simply because I knew it would be very messy very soon, which is to say it would have been unhealthy, and I didn’t want that at my back door.

My friend India Watkins discovered a wren nest perched on top of a deck broom propped against the wall. The deck broom had been up on tool forks for some time, so the wren family homesteaded between the bristles of the broom and the soffit, a clearance of about six inches. They’re opportunistic with their nests.

But they don't always follow their own rules. You’ll find all kinds of wren house designs with precise hole sizes and depths. Well, sometimes the wrens read those books and sometimes they don’t. I have two houses with ten feet of each that are opposites designs but wrens occupy both houses constantly.

In these two pictures there a couple of things to notice. The square outline is defined by the house itself and underneath the nest is the box’s removable floor. The wrens pack their housing materials in tight enough that when I pull out the floor the nest retains its shape. The sticks all seem to be magically the right size almost as if they’ve been sawed or else somebody spent a lot of time measuring sticks.

The other thing to notice is the Little Debbie wrapper which somehow wondered into the nest. That I don’t understand. Then there is the white string. They really like to use grass clippings and bits of straw because they’re flexible. String is always nice to use as well as fishing line but I’ve not seen any long strands of monofilament yet. Bits and pieces of thread are popular. Can’t say as I’ve found shoe laces, yet. Lint is ever popular.

The nest material has to be slightly flexible to get in the doorway, then bent to fit, but stay put, too. I’ve watched one parent poke a blade grass through the hole, then whoever is inside pulls it the rest of the way. The delivery parent is gone as soon as the one inside gets a grip and starts pulling. One box has a perch. The other does not. But, at nest building time no one stands around being a sidewalk foreman.

What might surprise us is that the number of sticks seems like they must have made a billion trips. Quickly, too. They build nests in a couple of days. Constant, running back and forth from the yard to the house. Chattering and trading off duties. It’s quite a project.