Our bird house has a tenant. Not the ideal tenant, but not House Sparrow riff-raff either.
For the first couple of months the bird house we put up in the drainage slump next to our house went unattended. By the middle of April I had just about given up on any birds taking up residence there. But last week, just out of idle curiosity, I lifted the lid of the box and was surprised to see the beginnings of nest in the box--lots of twigs, the bottom ones bent into a rough circle. A couple of days later there were more twigs, and on Saturday the box was really full of twigs to the extent that one was protruding through the entrance hole.
We were hoping for bluebirds. They're easy to find back in the WMA, but we haven't seen any in the slump for quite a while. We'd occasionally see them at dusk perched high up on the dead tree, but not lately. Today, I looked down the hill with my binoculars to the box and was lucky enough to see a bird dart out of it. Too fast to identify, but I knew it wasn't a bluebird. I waited a minute or so and the bird flew back into the box, again, a blur. When it stuck it's head out a moment later, I saw that we'd attracted a House Wren.
House Wrens are very aggressive birds, so there is not much concern that the House Sparrows I've seen around will push out the wren, and with the entrance tube we attached, I'm fairly certain that the Brown-headed Cowbirds won't be able to squeeze in to lay their parasitical eggs.
Now we'll just wait to see if we get a brood of wrens. Since I was dubious we'd attract any birds to the box, I'm pretty pleased with the results.