Last year I sent photos of Eastern Bluebirds nesting in a white birch tree. It was in the front yard of our northern New York State home. Well, it happened again this year. I missed the fledge this time, but here is a photo of one of the nestlings peeking out at its future world.
A few days after they fledged I noticed a pair of Pileated Woodpeckers working on the rotted trunk that contained the nest. I decided that I should measure the nest hole. It was more rectangular than round and measured about 1 and 3/4 at its highest and 2 and 1/2 inches across. Here is a photo of it. So, this hole was considerably larger than the ideal size 1 and 1/2 inch round hole that is standard for bluebird boxes. A week later, the trunk collapsed to the ground.
But all was not lost. Some 80 feet away there is a bluebird box at the edge of our hedgerow. Last year was its inaugural year. It hosted Tree Swallows followed by House Wrens. This year it was claimed early by House Sparrows. After their young ones fledged, a pair of bluebirds moved in before I had a chance to clean out the box. They built right on top of the sparrow nest. Here is the male with nesting material.
I monitored the box closely until we went away for a week at the end of July. By the time we left, the adults had been feeding chicks for several days. I was kind of surprised to find them still there when we returned. I missed the fledge (again) a couple of days later. I waited for my friend, the box maker, to arrive from Florida for a visit. We went out and opened the box. Here is what we found. Note the bluebirds' pale greenish materials on top of much older materials that the sparrows employed. It could be that the sparrows use grasses and plant stalks from the prior year that have yet to decompose.