The Box on the Snag

At the top of the cutbank behind the house stands a small American chestnut snag that I’d brought home from the Big Woods many, many years ago. As I would do with a wooden post, the snag was set in a hole about two feet deep; it stands roughly five feet tall. In the post was a cavity, a hole about eight inches deep with an entrance on the side of the post. The hope was that some of the birds in our area that are dependent on cavities for nest sites would use the hole in the post.

Use of the snag has been sporadic. During the first few years it was unused; then, each spring, as they often do, male house wrens began filling the cavity with twigs. Sometimes a pair of wrens would nest in the snag and raise a brood of young wrens –

During the winter some of the cavity-nesting birds, like this black-capped chickadee, would roost in the snag during the night –

Once a pair of tufted titmice nested in the snag. After the female had a clutch of four eggs a house wren punctured all the eggs and the titmice deserted the nest. House wrens often destroy the nests of other birds or may even kill the nestlings.

The snag had originated as a tree that was killed by the chestnut blight about 60 years before I’d brought it home. After another 20 years in the yard the buried portion decayed to the point where the snag fell over – the fall broke open the back of the cavity and snapped off part of the snag’s top.

Following that, I drove a metal fence post into the ground and used lag screws to hold the snag to the post; then a wooden nest box was fastened to the snag. Surprisingly the box, in the 20 years it’s been on the snag, has apparently been more attractive to birds than the original cavity.

House wrens stuff the box with twigs, just as they did the cavity in the sang – but the box is much easier to clean out.

And every few years the wrens raise a brood in the box –

Titmice and chickadees roost in the box on winter nights –

Black-capped chickadees often inspect the box as a possible nest site, but must find it unworthy because they’ve never nested there –

Other than house wrens, the nest box appears to be of most interest to eastern bluebirds. Beginning in 2015 eastern bluebirds have shown up at the box each spring; the male perches atop the snag and sings to declare his possession –

Shortly afterwards females also arrive and inspect the box –

But they too have apparently found it unworthy as a place to raise their young. What’s the problem? Is the box too large, too small, the wrong shape? To my eyes this box isn’t different than others of the same size and design that I’ve put in other places and where bluebirds have raised young. Do the surroundings have too many trees, too much mowed lawn, too many other birds, too many feral cats or don’t they like the neighbors? If only I could ask the birds.

This spring after the bluebirds appeared, the female began building a nest in the box on March 31 –

She worked on the nest steadily for several days following which the birds’ visits were few and far between.

Then on April 12 a pair of house sparrows appeared and began examining the box. Within minutes the bluebirds attacked the house sparrows. The female bluebird entered the box, came out immediately with the female house sparrow in a whirlwind of wings and feathers and both birds fell to the ground as the bluebird gave the house sparrow a thorough drubbing. My camera was in a distant room (*&%$#@*+@%) so there are no photos of the battle.

After the house sparrows fled, both bluebirds repeatedly displayed with widespread wings and much vocalization and fluttering –

By then the nest was completed but there were no eggs. There were still no eggs on April 30 and the bluebirds had vanished, so it appears the bluebirds have moved on once again – oh well, maybe next year.