Carolina Wren

So, I spent most of last week at work essentially playing a giant game of whack-a-mole with a local black bear that keeps destroying our bluebird boxes and eating all the chicks inside. After searching the literature a bit, we came up with an idea to dissuade the bear by spraying down the boxes with hot pepper wax and grapefruit seed oil (both of which are irritating to bears and not birds), but before we could try out the idea, I had to first rebuild all those boxes.

A Carolina wren removing eggshells from his nest in a workshop cubby.

While was working in the woodshop, I noticed two Carolina wrens that kept entering the barn through a little hole in the side and hopping around, eying me carefully. This isn't especially strange behavior - Carolina wrens are known for making use of human structures and exploring holes and crevices like little flying mice. They have even been recorded nesting in used boots and old coat pockets and, as such, I started to wonder if this pair perhaps had a nest somewhere in the building. The next time one of the birds came in, I put down my tools and watched. She was carrying a caterpillar in her mouth and, sure enough, after making her way across the work bench on the far side of the room, flew up to one of the storage cubbies on the wall above where there was a small nest full of peeping mouths. After feeding her chicks, the wren flew over to the window and slipped out of a crevice. 

A Carolina wren bringing a caterpillar to her nest full of newly hatched chicks.

A little while later, another bird entered - the male, I believe, since I heard him singing outside before he came in. He also had a caterpillar, but upon seeing me, stopped and began to call loudly. A few moments later, the female came in and, after what I suppose were some reassuring chirps from her, the male flew up to the nest and fed the chicks his caterpillar. He then removed a bit of eggshell from the nest and flew out the same gap near the window that the female had used earlier. 

This went on for most of the day, with one member of the pair coming in every few minutes with a worm or caterpillar to feed their growing family. I wasn't able to get an exact number, but I would estimate that I saw them come in with a few dozen insects at least. Early in their lives, baby birds need to be fed almost constantly, and having helped to raise birds for a rehab program, I do not envy their work. At least the pair has each other though - Carolina wrens divide the labor of raising their young evenly between the male and female partners and, unlike many other bird species, pair bonded individuals stay together for as long as they are both alive, defending a territory together even during the winter months. The family doesn't seem to mind the noise of the saws too much, so as long as we make a point of limiting our time near that particular work bench, I am sure that the babies will be able to fledge successfully!