Many people find cell phones to be essential, something that they cannot live without. But the popular devices are having an unintended consequence, one that is taking an environmental toll.Cell phones (and other modern electronics) require towers to transmit signals. Cell towers, in turn, require warning lights to make them visible to low-flying pilots.Researchers have determined that solid-red light on communications towers attract birds on dark nights, often resulting in the birds hitting the tower and dying. Courtesy of Joelle Gehring.To migrating birds, these solitary lights become beacons on dark and cloudy nights. They fly toward the lights at high speeds, often smashing into the tower, its supporting wires or each other. It is not unusual to find the ground littered with dead birds in the morning. In Madison, Wis., in 2005, researchers tallied 400 dead birds representing 23 species. While communications towers are nothing new, cell phones and other devices have spawned a building frenzy, resulted in thousands of new towers around the US alone in the past several years. More towers have resulted in more dead birds, some of which are listed as threatened or endangered species.Joelle Gehring, a biologist with the Michigan Natural Features Inventory in Lansing, has studied the problem and determined that solid-red light in particular seems to attract birds and, hence, cause more deaths. Removing solid-red lights (and relying instead on blinking reds or whites) might seem like an obvious solution. But solid-red light is required by the Federal Aviation Administration to serve as a warning signal for pilots. What must be determined is whether turning off the solid reds will put pilots at greater risk of collision with the towers. The government is studying the issue to see whether a mutually beneficial arrangement can be found that protects avian fliers as well as it does aviators.