A nest hidden in the arbor

Earlier this summer, we were enjoying watching a cardinal pair that seemed to have taken up residence in or near our backyard. I had figured they must have a nest nearby somewhere, perhaps in our neighbor's lilacs, or in one of the trees that have volunteered along the fence. By midsummer, the juvenile cardinals were everywhere calling out in their one piping note. They had not yet learned to whistle melodiously like their parents.

And then there was the plain brown young bird that was acting like one of the cardinal brood but did not look like a cardinal. We finally figured out it was a cowbird. The cowbird lays her eggs in other bird's nests, one here and one there, leaving it to the unwitting adoptive parents to feed and raise her chicks. Often, this is to the detriment of the host bird's offspring, but judging by all the young cardinals chirping about in our backyard, the intruder doesn't seem to have done them any harm. (Jim Williams wrote about cowbirds in his Star Tribune birding column here.)

They eventually matured and scattered and I pretty much forgot about them.

Then, a couple of weeks ago, I spotted a small broken speckled egg on the pavement under our narrow arbor leading into the backyard from the alley. We planted an American bittersweet vine on either side of it about five years ago and the vine has grown into a thick and rampant canopy. I looked up to see if I could spot where the eggshell came from and that's when I saw the well-hidden nest in the tangle of vining branches.

The location and size of it fits the description of a cardinal's nest provided by the Cornell Lab of Ornithology on their website All About Birds. The eggshell, however, could be that of a cardinal or a cowbird, they are similar enough that I really couldn't say — I'm certainly no expert, and I no longer have the eggshell to examine it.

I've recently seen and heard juvenile cardinals in our yard again, an apparent second brood, possibly from the same pair, but they don't use the same nest twice, and the one in the bittersweet does indeed look abandoned. 

No sign of a cowbird this time around.

(When researching information about cowbirds and cardinals for this blog post, I came across this terrific collection of photographs on a site called Wild Love Photography.)