Really, we should have known this wouldn’t be easy. As I wrote last week, a sparrow has made a nest and laid her eggs in our hanging planter. I’m rooting for these eggs to survive, as we’ve (the eggs, that is) had a three-year bad luck spell.
Luckily, I thoroughly enjoy learning about the animal kingdom because I now know more about cowbirds than any of you. That will soon change. (Bear with me — there’s a question I’d like to pose to you at the end. It’s an interesting one, I think.)
It seems a cowbird has laid an egg in the sparrow nest. This is bad because cowbirds hatch sooner and they are bigger. The bigger hatchling will most likely gobble up any food the sparrow brings back for her own brood, thus causing most or all of the other hatchlings to starve. And sometimes cowbird hatchlings push the others out of the nest. The prevalence of cowbirds has probably contributed to the decline of some songbirds (among many other factors, like our own prevalence).
Cowbirds are called brood parasitic because the mama bird will do this–lay her egg(s) in another’s nest and then that foster parent has to do all the hard work. In the past, this cowbird behavior has been attributed to everything from laziness to genius. I read several opinions that I should snatch the egg, shake it, and be done with it; I was even given this opinion by a wildlife biologist.
Not so fast. It used to be thought that the mama cowbird lays her egg and moves on. But a groundbreaking study found that some mama cowbirds watch the nest to make sure the foster parent is doing a good job. If her egg is removed, the mama cowbird will return and destroy the rest of the eggs. She will retaliate. These cowbirds mean business.
Add to your newfound knowledge the fact that cowbirds are a native species and are thereby protected by law. I’d technically be breaking the law if I shook that egg–though, from my brief research, it seems everyone does it.
I’ve always said I could never be a National Geographic photographer because I couldn’t just stand by and watch a lion stalk a baby elephant. I would have to save the elephant. But the lion cubs need to eat, too, and I agree with the principle that when possible, we should not mess with nature.
So–nature or nurture? I’ve pretty much made up my mind. What would you do?
P.S. I didn’t even tell you half of what I now know about cowbirds.