I was anxious to check the nest boxes this morning. With all the torrential downpours we’ve had lately I worried for the nestlings in the two remaining active nests. As it happens, it wasn’t the rain I needed to be concerned about.
The birds in the Cow Pasture nest next to the Train Tunnel seemed content as I opened their nest box. It’s difficult to see but it appears all five birds are still present. They will surely fledge before I peek into this box again.
The Bungee Jump, Sail Boat Pond, and Amphimeadow nests are all empty. I don’t expect any more activity in those boxes. I was surprised, however, to see the start of a House Wren nest in the box next to the Picnic Dome. I’m betting, though, that the bird or birds don’t follow through with this nest, wrens sometimes start nests in several locations and never finish. I’ll be checking as part of my routine just to be sure.
Here’s where the story gets interesting. The first thing that I saw as I approached the nest box at the Butterfly House was an adult male bluebird. It wasn’t sitting on the box or even in a nearby tree, it was belly up on the ground two feet in front of the nest box. The bird had no apparent injuries and hadn’t been dead for long.
The nest was empty and I thought for a moment that the nestlings had fledged, whatever had happened to the adult happened afterwards. I took a quick survey of the area surrounding the nest box. Scattered on the ground were pieces of wings and many wing feathers. The nest had been raided and at least some of the nestlings eaten, there were enough feathers present on the ground for perhaps two or more birds.
The others may have fledged but it doesn’t seem likely. Judging by the feathers found, they didn’t seem old enough to safely fledge, they couldn’t yet fly. Even if they survived the initial assault and were forced out of the box prematurely, they would not have survived long without being able to get up off of the ground.
It seems clear enough that some of the nestlings had been eaten. But why was the adult dead, but untouched. Why hadn’t whatever it was that ate the nestlings also taken the adult? I’m going to have to ponder this for a while. This nest box will have a predator guard installed before next season.
In the mean time, we have only one active nest, the Cow Pasture nest with five bluebird chicks. Although a wren nest has been started in the nest box near the Picnic Dome, I’m not counting on that nest being completed. But, as usual, we’ll have to wait and see what develops.