(This column was first published in the October 13, 2003 issue of The Buffalo News.)
It is that time of year again when skeins of Canada geese fill the sky, their mournful honking reminding us, as if the falling temperature did not, of the end of another growing season. Meanwhile other bird species gather into vast flocks that rise and wheel in the wind almost like smoke.
There are many questions that intrigue me about such aggregations. For example, I once watched a peregrine falcon approach a huge flock of starlings in flight. The response of the smaller birds was immediate. They tightened from a loose collection into a mass so dense that it was nearly black. I could also see the resulting conglomeration rotate as a single entity. Individual birds seemed to exchange positions within the flock so that each was on the side toward the predator only briefly. The hawk was apparently confused by this strange activity because, after flying parallel to the flock for several minutes, it veered off and dropped into a tree.
How in the world could the starlings accomplish these spectacular feats? The birds appeared to move as one with no apparent signal. Any marching band conductor would have been extremely jealous of their precision. Surely there must be some signaling going on within the flock, but how is it transmitted with such split-second timing? And how do the birds learn these maneuvers? Do they practice at night when we aren't watching?
Less rapid but just as intriguing is the V-formation flight of those geese. Are there physical savings to individual geese to be gained from such flight patterns? If there are, does the leader share in those gains or is that goose simply imposed upon? On a less serious note: is the leader goaded into accepting this role as a kind of show-off macho behavior?
I was hospitalized briefly during World War II with several Navy pilots and I asked them if they felt what their planes gained from flying in close formation. Their response was that energy gains were illusory and that the tight company was solely for military purposes. And they even provided evidence: they told me that on long flights there were no differences in fuel consumed between leaders and wingmen (it was strictly men then).
I remained convinced by their argument until recently when twice I had bicyclists closely follow my scooter. I asked each of the bikers if they felt they gained significantly from this and they both claimed a real advantage. They didn't have to pedal as hard.
So intrigued have I been about these matters that I have read several books on flying. My favorite is Henk Tennekes' The Simple Science of Flight: From Insects to Jumbo Jets. I like everything about his book except that word "simple" as the ideas seem most complex to me.
But then I found a 1988 article by John Badgerow of Syracuse University. He performed carefully controlled studies that compared formation and solo flight on two factors: energy consumption and the associated visual communication. Although many of his tests proved inconclusive, the results he does claim (partly from prior studies) are most intriguing.
"The geese realized an average savings of about 10% over solo flight," he tells us and he continues, "The advantage could translate as greater flight range [or] greater reserves at the end of a flight."
Part of the evidence he brings to bear on this claim is the discipline in distance and angle maintained by following birds that keeps them in reasonable position to maximize their gains.
So evidently the geese are indeed bouncing along on those air pillows compressed by their leader's wings. Gerry Rising