Editor's note: The original version of this column was published Nov. 26, 2011.
It's Thanksgiving week and time to crank out one of these columns without a time element. So I thought I'd test our collective knowledge this morning with a phenomenon familiar to most folks.
It's that season of the year again. You know what I mean if you've been watching the November skies across Arkansas at all.
Those enormous flocks of birds heading south for the coming winter are flying in unison when suddenly, their dark cloud makes a radical turn or dives precisely together as an airborne wave in a split second.
Not one wing nudges another as they suddenly swoop and climb and swerve this way, then that.
So how do they know? Who's in charge of this flight, for gosh sakes?
I was pondering just such a flock above my windshield the other day. And one day later, my daughter, Anna, called: "Dad, I have a question. How do those flocks of birds in the fall know when to turn together at the same instant?"
I had to laugh.
Of course, being a father, I hated to confess that at this stage of life I still had not a clue. So I made something up that sounded good.
"I think there must be a leader who somehow transmits an instant message, honey."
Hey, it sounded reasonable.
Later I did confess my ignorance, which led me to do a bit of research, assuming many of you have pondered this question as well.
Turns out these impossibly coordinated movements of flocks actually present one of the most intriguing questions in nature. Some who've studied the mystical question believe electromagnetic communication must be a part of it, or perhaps even the transference of a common thought between the flock.
But the phenomenon also has been called an example of "emergent behavior" among the flock itself.
"There is no leader, no overall control; instead the flock's movements are determined by the moment-by-moment decisions of individual birds, following simple rules in response to interactions with their neighbors in the flock," one explanation, posted on The Straight Dope website, reads. I had to read that passage twice and still scratched my head.
"Research by Wayne Potts, published in the journal Nature in 1984, helped explain how flock movements are initiated and coordinated," the site says. "Potts, through a frame-by-frame analysis of high-speed film of sandpiper flocks, found that any individual can initiate a flock movement, which then propagates through the flock in a wave radiating out from the initiation site." These 'maneuver waves' could move in any direction through the flock, including from back to front. However, the flock usually only responded to birds that banked into the flock, rather than away from it. Since birds turning away from the flock run the risk of being separated from it and getting picked off by the predator, others will not follow them. Besides its obvious benefits for individuals, this rule helps prevent indecision by the flock and permits it to respond rapidly to attack."
But there remains plenty of mystery to this question because once the wave movement begins, Potts found that it spread across the flock more rapidly than could be explained by individual birds' physical reaction times.
In the laboratory, a bird's mean startle reaction time to a light flash was measured at 38 milliseconds. Maneuver waves spread through the flock at a mean speed of fewer than 15 milliseconds. "However," reads the essay, "the first birds to respond to an initiator took 67 milliseconds to react. Potts proposed that birds farther away from the initiation site were able to see the wave approaching them, and could 'get set' to respond before it actually reached them."
Say, wait a minute. You don't suppose this phenomenon might be responsible for many of those massive bird deaths when they might mistakenly turn as a wave into catastrophic danger that wipes out the entire flock, do ya? Just thinking aloud.
And now we know that, while we humans (who usually wind up proved wrong over time in most things) might claim we understand why this occurs, there's still much to it about which we share not 15 milliseconds of authentic understanding.
------------v------------
Mike Masterson's column appears regularly in the Arkansas Democrat-Gazette. Email him at mikemasterson10@hotmail.com.
Editorial on 11/24/2015