A Murder of Crows

This isn’t a cozying up to wind post, but rather a how not to use numbers to make an argument post.

We were listening to a Senate hearing this morning and Senator Lamar Alexander (R-Tenn.) mentioned that wind turbines kill a lot of birds. He said this as a kind of aside about the problems of  electricity generators other than nuclear.

We have no idea why this idea has popped to the fore, but we’ve heard a lot of it lately. Here’s George Will on ABC’s This Week:

"By the way, wind farms kill a lot more birds daily than are probably going to be killed in this oil spill."

Well, yes and no – windmills don’t cause ecological disasters and those tend to be devastating to the future of a species, bird and otherwise.

Will had expanded on this comment in his Newsweek column a few weeks ago:

Wind power involves gargantuan "energy sprawl." To produce 20 percent of America's power by wind, which the Obama administration dreamily proposes, would require 186,000 tall turbines -- 40 stories tall, their flashing lights can be seen for 20 miles -- covering an area the size of West Virginia. … And birds beware: the American Bird Conservancy estimates that the existing 25,000 turbines kill between 75,000 and 275,000 birds a year. Imagine the toll that 186,000 turbines would take.

275,000 birds? Here’s Mrs. Bundy, the ornithologist in Alfred Hitchcock’s The Birds (1963), when asked why it is a doomed task to wipe out all the birds in the world (which in the movie are attacking humans):

Because there are 8,650 species of birds in the world today. It's estimated that five billion, seven hundred and fifty million birds live in the United States alone. The five continents of the world probably contain more than a hundred billion birds! [The current best estimates are between 200 and 400 billion birds worldwide.]

In point of fact, birds had to adjust to a creature determined to put large obstacles in their way a long time ago. We have no idea how many birds smack into cooling towers or nuclear plant buildings around the world – likely a smaller number than windmills, but some certainly. Birds will run into just about anything.

Will uses the American Bird Conservancy (cool group – worth a visit)as his reference, but fails to include other approximate annual bird kill counts the conservancy has compiled. Media Matters for America put a list together based on conservancy data:

Building strikes - 100 million - 1 billion

Car strikes - 200 - 300 million

Communication towers - 4 - 50 million

Power lines ~ 75 million

Cats - 365 million (1 million per day)

Wind farms - 100,000 - 300,000

Conclusion: context is all. One could very well decide that putting wind farms where they have to go – windy places – is too damaging to bird migration paths or is home to a nearly extinct species of bird – or other critter, for that matter. And that would be that.

But the number itself is not compelling. Looking at the American Bird Conservancy’s site, you’ll quickly learn that disease and rapid land development are far more effective bird killers than a structure (nuclear plant) or series of structures (wind farms).

This one’s a non-starter.

The origin of a murder of crows (or parliament of rooks, for that matter) is not known. It may be based on a folk myth that a flock of crows will “murder” members if it grows too large, but that hasn’t actually been observed to happen. Wikipedia has a list of these grouping terms.