The pace is frenzied: individuals jockey for position, constantly moving to maintain their spot against the flow. A promising look sparks a flurry of activity in the group, each hell-bent on reaching that final destination. At the point of convergence the weaker members give way, leaving a smooth ride in and out for the strongest and most motivated of the group. The heat of the moment gives way to a momentary calm that lasts until the next opening appears and the jockeying begins anew.
I’m not talking about corporate scandals, NASCAR, or pipeline (you can turn the volume down but wait for the wipeouts…); what I am describing is a common occurrence in almost any group of animals that desires access to a clumped, restricted or otherwise rare resource; in fact, it’s so common that it has it’s own name: the “lineup“.
You can think of a lineup as being a sort of stable hierarchy among individuals, where the stronger/more talented/more motivated/bigger/(add adjective) are at the top of the lineup, dominant to other individuals. This game plays itself out in crowded barnyards, crowded surf breaks, herds of gazelles, and flocks of birds.
(A lineup from my feeder in Sapsucker Woods: male downy woodpecker, female downy woodpecker, tufted titmouse, white-breasted nuthatch, black-capped chickadee)
If you watch your feeder carefully you will notice a pattern in who visits the feeder first, and who gets out of the way. The lineup extends not only to members of the same species, but also across species. For example, one black-capped chickadee may be dominant to the rest of his flock, but he gets the hell out of dodge when a tufted titmouse arrives on the scene looking for trouble. Usually males are dominant to females, older birds to younger birds, bigger birds to smaller birds. But sometimes it can be a bit confusing:
Tufted titmice are out-massed by white-breasted nuthatches; yet I have watched a white-breasted nuthatch consumed with impatience as a tufted titmouse takes his sweet time on the peanut feeder. The titmice are dominant to the nuthatches at my feeders (though it may be a bit different where you are-the relationship between nuthatches and titmice can be ambiguous), and the nuthatch spent his time pecking futilely at a branch in an act of displaced anger. Yet there wasn’t anything he could do about it, thanks to the rigidity of the winter lineup. And it’s not just access to food — the dominant birds also take the safest foraging strategies (.pdf) for themselves.
Not all birds will immediately fit into a size-based lineup. For example, red-breasted nuthatches are some of the most vicious little birds known to man, and despite their similarity in size to chickadees, they dominate them completely when a good opportunity presents itself. The carolina wrens appear to be utterly oblivious as they camp out at my peanut feeder, and some birds (like cedar waxwings) appear to get along all the time while feasting on abundant fruit.
So — when all is said and done, take a look at the aerial chaos surrounding a feeder and look for a pattern. Usually, you will find that it resolves itself in a very linear fashion — and that the entertainment value of watching a pair of woodpeckers squeak at each other is priceless.