In last week’s column, I looked at the “small-p-politics” of starling ecology. It seems that in the U.K., where starlings are native, people tend to overlook the negative aspects of their ecology. In the U.S., where starlings are an introduced species, however, people tend to minimize the positive aspects of their ecology.
In reality, whether they are protected, as in the U.K., or disparaged, as in the U.S., the birds don’t care. They continue to fill their ecological role, eating, digesting and dispersing seeds and insects, and themselves being eaten.
In Europe, starlings feed not only hawks and falcons as in the U.S., but they also feed humans (pate de sansonnet in France). For me, as an American, the dark cloud that hangs over invasive starlings has prevented me from appreciating them. One feature of starlings I have looked at with only the slightest curiosity is called murmuration.
Murmuration is the term used to describe the flock behavior of starlings. The synonyms shoaling, swarming, and herding are used for fish, insects and livestock. The most dramatic instances of murmuration happen in agricultural settings, where thousands of starlings form giant black, gyrating clouds. The clouds morph themselves in wave- and funnel-like responses to half-hearted attempts at predation by lone peregrine falcons. It seems that the nourishment that starlings offer to falcons is not sufficient enough to warrant more aggressive hunting. So the falcon and the starling cloud becomes more of a dance.
As a lifelong suburbanite, however, murmuration of that magnitude is not the starling movement most stamped upon my mind. Instead, I envision merely scores of starlings moving synchronically from power line perch to commercial lawn and tree and back. I have mockingly wondered what petty concerns drive this flock mentality.
It turns out, some researchers recently marshaled powerful computer and video technology to investigate the murmurous “mechanics” of starling flocks. “Scale-free correlation” is the term that describes Andrea Cavagna and colleagues’ discovery. Murmuration thus starkly contrasts the old “telephone game,” in which quickly a phrase like, “Eli says, ‘achoo!’” becomes “Everybody hates you.” “Scale-free” means that information moves through the flock with perfect efficiency.
Additionally, a group led by George Young discovered that this efficient flock information travels by the magic number seven. As the flock moves, each individual tracks and responds to the movement of its seven nearest neighbors.
Evolutionary biologists who ponder such phenomena conclude that starlings (and other communal creatures) have “realized” that they are safer in community and so have developed finely tuned flocking skills as a result.
I am both glad that lions have not figured this out and developed armies, and that honey bees have over-achieved by building colonies. Some humans have relatively mastered collective life, but others still choose to go it alone. And, there are still seven “Joneses” most of us mindlessly chase.
Joshua Arp is an ISA-certified municipal specialist, Clarks Summit’s municipal arborist and an operator of an organic lawn and landscape maintenance business. Reach him at firstname.lastname@example.org.