Big Bad Bird

I've written before on the pecking order that birds establish at our feeder. Certain species of birds dominate or intimidate other species, in order to get first dibs at the feeder. Most often, the hierarchy appears to be determined by the relative sizes of the birds—but not always. While the larger cardinal will invariably dominate the smaller titmouse or chickadee, the smaller goldfinch will easily chase off the larger titmouse.

How can the more petite finch intimidate the bigger titmouse? I doubt that the small finch is conscious of its more diminutive size, since I would guess that most birds have no comprehension of how large they are. If they can't recognize themselves in a mirror (which they adequately demonstrate by pecking at their own reflection in a window), how can they have knowledge of how large they are, relative to another bird? It's got to be more than size.

In the case of a goldfinch facing off a titmouse, even though the former is smaller, its bill is far stronger. The finch can crush a hard seed with its tough beak, while a titmouse must lodge the seed in its claws and bang away repeatedly with its weaker bill, until the seed yields its hard shell. If the two of them were to engage in a battle for pecking order, the smaller goldfinch could deliver a painful bite that the titmouse would long remember. I think that Nature has built into the titmouse an innate knowledge that it would be foolish to challenge the finch. So the safe thing for the titmouse is to defer to the finch, wait, and go for a seed after it has satisfied itself.

The term pecking order comes form the jostling that occurs between barnyard hens, as they establish their hierarchy. The chickens' process must be different from songbirds, however, because chickens are one species, are similar in size, and in beak force. Their pecking order seems to be determined by experience; by conflict. It can be a rather vicious process to watch, but once the chicken hierarchy is resolved, relative peace reigns. For them, it’s not a case of an instinctive response, as it is for songbirds. Chickens learn it; songbirds inherit it.

On rare occasions I have observed a lower-order bird challenge a superior one, at the feeder. Aha, I think, it’s going against its inherited tendency! Something interesting is happening here. Is the normally less-dominant bird ignorant of its place in the pecking order? Is it foolishly taking a chance? Maybe it just accomplished a feat that required unusual bravery and is high on its audacious stunt? In these cases, sometimes the challenger wins, but I suspect that it will later come to its senses and once again defer to its evolutionary overlord, at its next trip to the feeder. Evolution does prevail, in the long run. The pecking order is perennial.