Admirably adaptable strategist
I nominate the brown-headed cowbird as Canada’s national bird. Yes, even though the cowbird is almost universally reviled, I nominate it as a reminder of the invisible human hand in the environment.
I admit it’s not easy to watch a tiny fly-catcher desperately feeding the giant cowbird chick that she has faithfully raised, while losing most of her offspring at the same time. She didn’t volunteer for the task; she was outmanoeuvred. But you have to admit it is a brilliant evolutionary strategy. Why waste time and energy solidifying your genetic future when someone
else will do it for you? This practice, called nest parasitism, has evolved in many species around the world, but the cowbird is the Canadian representative.
Well, OK, it’s in the U.S. too, but when it comes to nature, borders are irrelevant (think whooping cranes). So, why argue that cowbirds should become a permanent reminder of human interference in the environment?
Cowbirds are admirably adaptable: they established themselves in North America
by following the vast bison herds (or even the large mammals of the Pleistocene
before that), eating the insects flushed out of the soil by the ungulates’ hoofs or attracted by their droppings, and for centuries the birds’ range was delimited by those animals. When Europeans did their best to extinguish the bison, was it lights out for the cowbird? No, they simply switched to following cattle.
But they got their big break when we humans began to clear the forests for farmland. That clearing exposed many forest-dwelling birds to cowbirds for the
first time, especially along the forest edge. Not only does that mean that the most vulnerable species simply haven’t had time to adapt to the existence of a bird that will hijack their parenting, it also points the finger of blame squarely at us.
So the revulsion we feel when we see cowbirds victimize some of our most
beautiful songbirds is real. At the same time, we have to admit that we are as
responsible as they are.