Mass Animal Deaths: An Environmental Whodunit
Liz Condo/The Advocate, via Associated Press
Hundreds of dead birds lay along the side of a Louisiana highway on Monday, about 300 miles south of Beebe, Ark., where thousands of blackbirds fell from the sky three days earlier.
By JAMES GORMAN
Published: January 8, 2011
When 5,000 red-winged blackbirds fell dead on New Year’s Eve in Arkansas, and 500 more in Louisiana, many people immediately looked for a villain. There was speculation about military tests and pesticides, and a lot of wondering whether the bird deaths and other incidents, including the mass deaths of fish, were linked.
Related
For Arkansas Blackbirds, the New Year Never Came (January 4, 2011)
Even very plausible explanations did not allay the suspicion that something sinister must be going on. Why? Because we’re human. Our minds have evolved to look for patterns, and causative agents. In fact, some thinkers argue that this turn of mind, which evolved as a survival mechanism, ended up predisposing humans to believe in a deity, because when we can’t find a natural cause for an apparent pattern or event, we posit a supernatural one. Certainly it predisposed us to look for an interesting culprit for the bird die-offs.
One of the writers to suggest how we ended up this way is Michael Shermer, the founding publisher of Skeptic magazine and a Scientific American columnist, who uses a common scenario to explain why we believe in things that may not be there — hominids on the savannah hearing a rustling in the tall grass. The one who thinks, “It’s a lion!” and escapes quickly survives to propagate her genes, thus fostering a kind of protective alarmism in her descendants. Another might think, “There’s always some kind of rustling in the tall grass, it’s probably the wind,” and keep on grooming. If he guesses wrong, the downside is being eaten by the lion. Thus, no offspring and no propagation of the “don’t worry, be happy” genes.
Of course, people have both modes of thought, perhaps because rustling is usually caused by the wind, and the hominid who is too alarmist is always running away from nothing and probably too exhausted and too anxiety-ridden to mate. So there’s room for both the wind and the lion in human minds.
Clearly, however, lion-think prevails, because wind-think is so unsatisfying. Mundane and probably correct explanations for events like birds falling from the sky leave us emotionally unconvinced and yearning for something more.
What really did in the birds?
Melanie Driscoll, a biologist and director of bird conservation for the Gulf of Mexico and Mississippi Flyway for the National Audubon Society, said preliminary tests showed no evidence of viral or bacterial disease, toxins or poisons, but there were reasonable explanations.
“In Arkansas, we have eyewitness accounts that professional-grade fireworks were set off in a town near a known blackbird roost,” she said, “and that birds flushed from the roost and flew in a single direction at lower levels than they would normally fly. We know that they cannot see well in the dark and we know they were seen crashing into buildings and cars and poles. Necropsies show blunt force trauma to brain and breast.”
As for the hundreds of red-winged blackbirds found dead in Pointe Coupee Parish, La., a few hundred miles from the Arkansas die-off site, they were found along rural roads under power lines, which are thin and difficult to see at night. The theory is that those birds were also spooked by holiday fireworks, and ran into the lines.
It’s worth keeping in mind just how many birds there are when thinking about so-called mass die-offs. “Five billion birds die in the U.S. every year,” Ms. Driscoll said, “so statistically some have to die at the same time.” The population of red-winged blackbirds is more than 200 million, she said, and they fly in flocks of 100,000 to 2 million. “So 5,000 sounds like a lot of birds, but really it is a relative number.”
All of this makes sense, and yet leaves us craving something more. We hear the numbers. We recognize the rationality of Ms. Driscoll’s explanation and yet, some of us think, birds falling from the sky? There must be something else going on.
Me, I’m betting on zombies. Has anyone checked to see if any dead birds are coming back to life? It may sound silly, but imagine the downside of missing the first signs of a zombie epidemic. Human beings would become walking bird feeders for the beaked undead.
Not a pretty thought. Not a possibility to ignore, if you have a lion turn of mind.
Of course, it’s probably just the wind.
No hay comentarios:
Publicar un comentario