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.

Pecking Order—Part 2

The usual factors that determine wild bird pecking order are size, age, hormone levels, and how much ownership of the feeder a given bird feels at the moment (its belligerency level?). As younger birds mature, or their hormone levels change, they become more likely to challenge the existing order set up by their elders (sort of like teenage kids who challenge their parents). The underlying factor that powers the whole thing is reproduction: the drive to send one's genes into the future. Those who get the lion's share of food today are most likely to stay healthy and generate offspring.

We have observed minimal physical contact at our feeder, when pecking-order jousts occur. It's mostly a case of a show of bravado—like teenage boys strutting before each other in a menacing manner. No one really wants to fight—just to force his opponent to back down, in the face of his excessive swagger. Now and then, however, we do witness a real bird battle, as the contestants go a little too far in their bluff and now must save face by actually fighting. The confrontation rarely lasts more than a moment or two, and neither fighter gets harmed—one immediately blinks and the duel is over.

Researchers have also noticed two types of pecking order: what are termed despotic and linear. When a despot is on the scene, all other birds make themselves scarce. A blue jay arriving at the feeder will scatter all the little birds, who stay away until he's gone. In contrast, barnyard hens set up a linear pecking order, in which each one knows her place in line—never challenging those above her, nor challenged by those below. We also see that linear pecking order in our wild birds at the feeder—at least between species. A titmouse will never challenge a wren, for example. Again, the linear pecking order may be occurring within a species, but our inability to tell one chickadee from another keeps us from knowing this.

So I have come to realize that the pecking order established by birds is a way for them to reduce conflict between them, rather than just be a way of picking on each other, as I used to view their interactions. It's another of those situations when we must be careful not to project onto animals the nature or our human social interactions. When I think about it, I can see many kinds of human pecking order that get established—most always based on power. Some examples are within families (so-called hen-pecked husbands), within social groups (the macho guys dominate), and between countries (those with the bigger armies get to peck).

Because the human types of pecking order are more familiar to me, I don't tend to see the inherent injustices that they express, unless I step back, pay attention, and pick up on the power relationships going on. I would guess that birds who might watch humans interact with one another would wonder why some of them so meekly accept the hierarchical structures.

Pecking Order—Part 1

For several years we have been entertained by the various kinds of activity at our birdfeeder. Some dozen or so species come regularly for seeds—often in waves. There'll be not a soul out there for an hour or so, then when you look a moment later, it'll be swamped by 15 or 20 birds. Is this a follow-the-leader game or do they have specific times of day that are mealtimes and they all answer the call simultaneously? Why don't a sneaky one or two hit the feeder alone and have it all to themselves? Are they aware of being safer in a group, when many eyes keep a sharp lookout for predators? These are more examples of some of the mysteries of nature that I try to attempt to solve, by keeping a sharp lookout. As I said, it's one of our favorite forms of entertainment, and it's a blast when your field of research is also what entertains you.

When the feeder becomes crowded there is a definite amount of contention that arises between its visitors and it gets expressed in an explicit pecking order. As one might expect, the bigger birds generally are “top dog,” but size is not exclusively the determinant. Sure, a blue jay will scare off a titmouse and a wren will never challenge a cardinal. But one of the smallest birds is the fiercest: the diminutive goldfinch. He'll drive off a bird twice his size with a fierce display of that strong, threateningly open bill.

There is both an interspecies and an intraspecies pecking order that gets established at the feeder. We've watched the interspecies battles long enough that we can pretty well guess which kind of bird will intimidate another. Cute little chickadees stand on the bottom rung. Among the small songbirds, titmice come next, then juncos, wrens, and finally nuthatches.

But, as I said before, the smallest of the little birds—the goldfinch—rules the roost of the bantam birds. I sometimes wonder what gives them that level of bravado. If I could hold up a mirror to one of them—and if it could recognize itself and see how little it is—I'm sure I could destroy its puffed up self-confidence and cause it to cringe when a bigger bird comes round. But that's messing with Mother Nature—and that can get you into trouble.

My ability to understand intraspecies pecking order, however, is nil, since I am still unable to distinguish one titmouse from another. They certainly seem to be able to recognize one another, however. Oh how I wish I could put a dot of different color paint on the top of each of their heads! What might I learn?

The term pecking order originated long ago, when people watched how chickens in a barnyard flock set up a hierarchy. Once the order is established, it remains quite stable. Hens settle their squabbles and the order stays pretty much fixed—the one who becomes alpha fowl will tend to remain so. In the wild, however, bird hierarchy may shift through the season, as different species get ready for mating and hormone levels vary over time.

Researchers have also noted that an established pecking order reduces conflict within a flock of chickens. In other words, when a hierarchy gets set up, the birds engage in fewer battles than will an unordered flock. That surprised me, as all birds—especially chickens—seem to me to be constantly at each other. But I guess that's another projection of mine onto nature: what appears to me to be quarrelsome behavior is really a way of attaining a little peace for them. I can't expect birds to behave politely with one another, just as I can't expect politicians to care more for their constituents than they do for the big monetary contributions they receive.

Next time: Setting up the pecking order...

From Flocking to Fighting

One of the joys of spring is watching and listening for the return of migrating birds. Those first calls of the phoebe, the robin, the wood thrush, or the indigo bunting are sure to bring wide smiles to our faces and an excited, “Did you hear that!?” All’s right with our little vernal world when we know that our winged travelers have come back for the season.

But there’s another fascinating spring event that I like to observe: the year-round resident birds, as they morph from close-knit feeding buddies in a flock, to sparring rivals, who enter into courting rituals.

Throughout the winter we have chickadees, titmice, and goldfinches flocking at the feeder—maybe a dozen or more of each species. To my untrained eye years ago, they all seemed to be close-knit friends, but that was a bit of anthropomorphizing on my part. Birds rarely are friendly with one another—tolerant is a better word for it (at best). In fact, they most always aggressively establish a pecking order that determines who dominates. At the feeder, sweet little chickadees are the most submissive and intimidated. Titmice pick on them, while they in turn are subservient to finches and nuthatches. Small woodpeckers come next, topped off by the cardinals.

But there’s also a harder-to-distinguish pecking order that gets established within each species. It’s more difficult to follow, because I’m as yet unable to tell one titmouse from another. Thus I can detect a hierarchy process going on, but do not know which bird is boss, or if he stays boss for long.

Despite the pecking order dynamics, however, during the winter the birds flock together in a decently non-combative manner around the feeder. Come spring, though, inner mating urges begin to control their behavior. It’s combat time. Winter’s proximity gives way to spring’s territorial jousting. The birds begin to call incessantly, in order to establish their mating and breeding turf. It’s fun to watch their antics, as they begin to challenge each other for the nicest patch of ground. They dive, feint, chase, squabble, show off, sing vociferously, and just as quickly stop and perch next to one another, as if a truce was suddenly called.

I’ve read that the dominant male of each species (the one in command at the winter feeder) gets the first pick of breeding territory. Around here that means the clearing, as it’ll have the highest population of insects during the summer. Maybe someday I’ll learn how to trap and band birds, so I can identify individuals. Then I can verify if Dominant Tom Titmouse at the feeder is the same guy whose mate now reigns in the nesting box in the back yard, or if Submissive Sam managed to outwit Tom or sing better than he did, and get the prime location.