In Alfred Hitchcock’s 1963 film The Birds, a California town is besieged by thousands of attacking seagulls, crows and other feathery foes, whose murderous ire toward humanity goes unexplained. If not an avian protest against DDT use (chronicled in Rachel Carson’s 1962 book Silent Spring), perhaps Hitchcock’s birds were attempting to prevent the slaughter in the skies caused by communication towers, which kill about 7 million birds annually in North America, or wind turbines, which kill about 400,000. Birds, which kill insects by the billions every year, are a critical part of all ecosystems.

 

A newly published study, conducted primarily by Professor Travis Longcore of the University of Southern California, finds that the problem is almost entirely with very tall towers, those that rise above 300 meters (984 feet) in height. Of the 84,000 communication towers that dot North America, only 1,040 are this tall, yet they account for about 70% of the bird deaths, or about 4.5 million a year. The birds are generally killed not by running into the towers themselves but into the dozens of cables, called guy wires, that hold them up, and which birds often cannot see.

 

By way of comparison, the St. Louis Arch is 192 meters tall (630 feet) and the Empire State building is 381 meters (1,250 feet).

 

Happily for the birds, according to Longcore, the deaths are by no means inevitable. “This is a tragedy that does not have to be,” he insists, noting that changing steady-burning lights to flashing ones on the 4,500 towers taller than 150 meters (490 feet) could reduce mortality about 45 percent, or about 2.5 million birds every year.

 

Meanwhile, the Energy Department recently released voluntary guidelines intended to reduce deaths from avian collisions with wind turbines, calling on the wind industry not to locate wind farms in areas that pose high risks to birds and to alleviate problems by restoring nearby habitat and other actions.

-Matt Bewig

 

Almost Seven Million Birds Perish at Communication Towers in North America Each Year (by Eddie North-Hager, Science Daily)

An Estimate of Avian Mortality at Communication Towers in the United States and Canada (by Travis Longcore, Catherine Rich, et al.) (pdf)

Wind Farm Regulations From Obama Administration Aim To Lower Bird Deaths (by Matthew Daly, Huffington Post)

Canadian Wind Turbine Kills 10 Birds and Bats a Day (by Noel Brinkerhoff and David Wallechinsky, AllGov)