Radio and TV Towers Killing Songbirds; Solution Is Simple


Longcore said the most impressive change so far is at the Federal Communications Commission, which has authority over the towers. The FCC has hired avian ecologist Joelle Gehring, who lead a large study of tower deaths in Michigan that found that when a steady light is replaced by a blinking light, the birds simply leave.

Gehring contends it's not expensive, and the results are immediate.

Of course, all of this is based on estimates, some of which wildly disagree with estimates from other researchers, and that may be partly because the situation varies so dramatically across the country. The songbirds suffer the most losses in the South and Midwestern U.S., so those estimates are not going to coincide with estimates from the far north.

And just simply collecting the data is difficult. Longcore said a dead bird doesn't hang around very long.

"Scavengers and predators and decomposers are incredibly effective at recycling spare nutrients lying around," he said. In one case an owl was spotted as it zipped through the night sky and grabbed small birds before they even hit the ground.

Even professional researchers probably only find about 20 percent of the victims because the bird deaths take place at night and scavengers are on the job.

However, sometimes it's easier to find how many birds have died. Scientists found that an estimated 5,000 to 10,000 birds, mostly Lapland Longspurs, were killed on Jan. 22, 1998, near a 420-foot tower in western Kansas. It happened, as is often the case, during a heavy snowstorm.

And the number of kills from towers still lags far behind the estimated number of deaths caused by birds hitting windows. And still, the estimates vary widely. One group of researchers, for example, estimated that the number of window-kills was somewhere between 97.6 million to 976 million annually.

Even Longcore admits that his own group's estimates are just that, estimates.

"We frankly and completely acknowledge that this is a sophisticated back of the envelope estimate," he said.

So if the numbers are right, why don't we sometimes find ourselves up to our eyeballs in dead birds?

"Don't forget these numbers come out of the sheer number of towers and windows across the continent," he said. In most cases, the number of deaths at any one site on any one evening might be low, but when multiplied by the number of towers in America (about 84,000, and growing each year) the aggregate can be huge.

By the way, the tallest towers claim the most birds. Towers over 900 feet tall are blamed for 70 percent of the deaths.

Longcore said he believes that if most of those are modified, just by switching to flashing lights, many more songbirds will be around to serenade us in our gardens.

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