There was a time in the not too distant past when bluebird sightings were a cause of celebration. The advent of the Peterson bluebird box and The Virginia Bluebird Society has reversed that. Now, it’s not unusual to see the blue streak of the male racing across the yard to the roosting place. In the last five years I have at least one successful brood, most years two, and one year three. That comes out to about three dozen new birds over the time I have been working at this.
Much has been written about box design and placement. Ten yards or so from a wooded area, five feet above the ground, and preferably facing northwest should bring results. I have found that not everyone is so fortunate.
Sparrows, of which there are several thousand varieties (so it seems) and tree swallows are also cavity nesters that are more than happy to fight for squatter’s rights. The tree swallows are not nearly as serious as the sparrows in competing with the bluebirds. After whirling around the box for a day or two they usually give up and move on, Not so with the sparrows. Not only will they take over a box that has a bluebird nest in it, they will kill the bluebird, attack the hatchlings and then build their own nest. The trick is to destroy any nesting attempts they make in an empty box, but once the bluebirds are brooding then it’s up to them to defend their turf, which they frequently fail to do.
In talking with bluebird aficionados we have picked up a few tips. While I have never had any trouble in my yard, Beloved has never been able to have a successful nesting. The sparrows have always won, leading us to give up and close the box down rather than find a dead bird in the box. House wrens are equally viscous, but less in number.
Sparrows like an unobstructed flight line into the box. Hanging a weighted fishing line in front of the hole is supposed to be a deterrent. It worked for a while, until a red-winged blackbird got tangled up in the line and was about to kill himself struggling for freedom. Fortunately, he finally escaped. The sparrows may have been watching, because the next day they ignored the warning string and started a nest which we promptly removed before they were near completing.
This year we heard of another tactic. Sparrows apparently don’t like things waving in the breeze in a landing zone. This seems counter-intuitive when you think about leaves in the wind, but we thought we would give it a try. We attached an American flag to the back of the box and bravely did it wave. The birds, all of them, were curious and inspected it from a distance but by the second day, it was obvious who had the upper wing, so to speak. A male bluebird was perched on the top of the flag watching his mate pick feathers from under her wing . . . a sure sign they were going to nest. The next day, the nest was complete, as neat as a pin and totally unlike the mess the sparrows throw together. Soon we had four hatchlings.
Bluebirds are naturally easy-going. They don’t mind you opening the front of the box and checking on them. Early after dawn, they lay their eggs, one at a time. They do not start brooding until the clutch is complete, usually four to six eggs. They will hatch in about 16 days after the last egg is laid.
The sparrows watched all this, figured out (even though they are English) that the flag was no threat, so in they went. Beloved then had an excellent idea: hang a yellow plastic ley (courtesy any Polynesian restaurant) on the side of the box. The sparrows freaked out, the bluebirds built a nest and now we have four more chicks.
After they fledge it will be interesting to see if the sparrows return. If they do, a wind chime is the next step.
This is great fun and you likely will be rewarded. It’s worth the effort. They don’t call them the Bluebird of Happiness for nothing.