When you sit in your backyard watching the bird feeders as regularly as I do, occasionally you get lucky and see something really out of the ordinary. I had one such a sighting on a June afternoon. I was reading my book in the yard, keeping an eye on the feeders and my camera on my lap, just in case. I noticed that I had a Carolina Wren on my feeder. While I have had House Wrens and Carolina Wrens in my yard before (just last summer a pair of House Wrens occupied one of my birdhouses) they are still a rare enough visitor to illicit a little extra excitement from me. So I was happily snapping away for quite a while. Long enough to realize that it wasn’t one Carolina Wren visiting my seed feeders, but a pair. They seemed to be visiting the feeder, stocking up and flying off. To feed a baby I assumed, which is a safe guess regarding that type of behavior in June. After a while I thought about the situation in more detail. Wrens had been in my yard before, but never visited the feeder because…suddenly it clicked that they only eat insects. They do not eat seeds or feed them to their nestlings. So what the heck were they doing carting off all my seeds?!
At the rate they kept disappearing and reappearing I decided they couldn’t have been going very far. So I decided to investigate. Very slowly I got up from my chair and slowly skirted my way around the bird feeders, making a very large circle so as not to scare and scatter the other birds eating. From my new vantage point I could see that the Carolina Wrens were landing on a low branch in one of the trees that represents the boundary between our yard and the neighbors’. So very, very slowly and making many long pauses along my way, I slowly advanced toward the branch in question.
Once I made it more or less directly under the tree, the whole picture began to take shape. What I found on the branch was a giant fledgling. Well, giant compared to the Carolina Wrens. It was exhibiting typical fledgling behavior, making lot of noise, moving awkwardly and opening its mouth to indicate that it was hungry. While I was trying to determine exactly what this fledgling was and how it fit into the larger mystery of the Carolina Wrens and my birdseed, one of the wrens landed next to this massive baby and began to feed it the seeds. And it all became clear. Well sort of.
After some research I was able to determine that the fledgling I had seen was a young Brown-headed Cowbird. As I mentioned in my post about them, Brown-headed Cowbirds do not incubate or raise their own chicks. Instead they lay their eggs in the nests of other birds in the hopes that some will survive. Many birds recognize the Cowbird eggs as impostors and either remove the eggs from their nest or destroy the eggs. However, still other species, such as the Wrens that feature in this story, keep the Cowbird eggs and treat the chick as their own.
Of course one could choose to look at this tale with cynicism and negativity. Yes, it is awful to think that the Carolina Wrens eggs likely perished and the pairs was left with this huge demanding impostor. Almost an ugly duckling story, if the ugly duckling had been less sad and much more demanding (which, in reality, as a young swan, he probably would have been). And then there is the obvious question…how dumb are wrens that they think this thing could possibly belong to them? Even as a baby he towered over them both. But what really grabbed at me was that they had figured out to feed him what it was he needed to eat. How many other animals would have realized… “honey he really doesn’t seem into the spiders and the grubs, maybe we should try seeds and see what happens?” How did they know? Instinct? Because if it is instinct, that opens an even greater realm of possibilities. If they have the built in instincts to feed the Cowbird babies, perhaps nature gave them the instincts so that the Cowbirds, rejected from so many nests, would find one species of willing foster parents. So while many bird lovers are bemoaning the fact that the Brown-headed Cowbird kills the eggs of so many different songbird species, maybe they should stop and consider that nature does everything for a reason. The Cowbirds are just as necessary as the Carolina Wrens.