Just why seabirds are drawn to light is poorly understood, but one theory is that they have a hard-wired attraction to the lighter color of the ocean, which allows them to leave the land and go to sea to feed. Travis Longcore of Urban Wildlands, a nonprofit based in Los Angeles, suggests another possibility: when fish swim through bioluminescent plankton near the ocean's surface, the moving swash of light may signal the presence of prey. Keitt told another story, of a fishing boat in Alaska: attracted to the boat's lights, so many birds were landing on the vessel that the crew feared that they would actually sink it. The captain ended up turning off the lights and shoveling the birds overboard. In the darkness, the onslaught ceased.

In fact, turning off the lights, though in that case an act of desperation, has been found to be an immediate and effective solution to the problem of bird strikes. FLAP's Mesure told of a power generation station on Lake Ontario with two floodlit emission stacks 15 to 20 stories high. "There was a noted history of bird strikes occurring at these stacks. Then in a single weekend, over a two-day period, some 10,000 birds were salvaged from around this structure." After a study concluded that the illumination was to blame, strobe lights for pilot navigation were substituted for the spotlights, "and the problem pretty much disappeared," Mesure said. "You will find no other environmental issue out there that is so easily resolved. How often can you say that you flick a switch, and it disappears, it stops? It's a win-win situation--everyone benefits: you save money, you save energy, you reduce pollution, you see the night sky, and you reduce bird collisions."

A recent study of communication towers in Michigan showed that tall towers (greater than 500 feet or so) and guyed structures were significantly more likely to kill birds than medium towers and self-supporting structures. An equally important factor in avian deaths, however, was lighting. And the findings supported the Lake Ontario conclusions: flashing lights lead to considerably less avian mortality than steady-burning lights.

Longcore said that it's not known why steady-burning lights have this effect. "It could be this sort of overwhelming not wanting to leave and go into the darkness, once they're in the cone of influence. You can imagine if you're around a campfire at night: that's a powerful thing that prohibits you from adjusting to going out into the darkness. If you steel yourself and walk away and close your eyes and adjust a little bit, then all of a sudden you can see. But when you're right around it, it's like this overpowering visual stimulus."

Currently, Federal Aviation Administration (FAA) guidelines specify that a tower must have flashing lights. White strobes can be used alone, but these tend to be obnoxious to nearby residents. Red flashing lights are the alternative; the catch is, they must be paired with steady-burning red lights. Joelle Gehring, conservation scientist with the Michigan Natural Features Inventory, explained that when the guidelines were established some four decades ago, the white strobe lights were found to act "like a camera flash to a pilot's eye; it gives some sort of depth perception. The red flashing lights were not as present to the pilot's eye, so they needed steady-burning lights as well."

When the FAA gave permission for some of the Michigan tower lights to be manipulated, the results were definitive: steady-burning lights, even if flashing lights are present, increase the number of birds killed. Encouragingly, the FAA has recently committed to conducting conspicuity studies with an eye to changing the guidelines. "With modern technology for pilots," said Gehring, "can we indeed turn off those steady-burning red lights and still have pilot safety? They're pretty optimistic about either turning them off or making them only flash, and they can do both those things from the ground," without the need for expensive retrofitting. "That would reduce avian collisions by as much as 70 percent. It's not obnoxious to the neighbors, it's essentially free, and it would save electricity and maintenance costs as well."

Again: it's a win-win situation--but one that will depend on voluntary efforts, since the FAA, assuming it approves the changes (which could happen as soon as 2010), will only allow them to be made; it will not mandate the changes. It will be up to individuals and organizations near the many communication towers sprinkled across the United States to ask tower operators to switch, and to make the case for why they should. (California alone, as of 2004, had 652 communication towers, 12 of them over 800 feet tall.)